WASTE DISPOSAL

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WASTE DISPOSAL
By Heidi Rowlands November 2003
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WASTE DISPOSAL

• What is waste?
• Who monitors and controls the disposal of waste?
• How is it disposed of?
• Disposal of waste to landfill

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WHAT IS WASTE?

• Waste is rubbish people at home and work discard
  because they no longer need it.
• England and Wales produce 400 million tonnes of
  waste every year.
• Careful management is needed so its effect on the
  environment and human health is minimal.

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TYPES OF WASTE

• Controlled Waste
• Household, industrial and commercial waste
• May be classified further as
• Inert
• Non-Hazardous
• Hazardous
• Non-controlled Waste
• Agricultural, mining and quarry waste

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TYPES OF WASTE (Cont.)
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Around 70 of controlled waste is sent to
landfill.
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WHO MONITORS CONTROLS THE DISPOSAL OF WASTE?
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WHO MONITORS CONTROLS THE DISPOSAL OF WASTE?
Independent Consultants
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THE ENVIRONMENT AGENCYS ROLE

• The EA regulates waste management through a
  system of licences (PPC Permits).
• The EA waste team is responsible for ensuring
  that waste produced in England and Wales is
  correctly disposed of, in a manner that minimises
  its impact on people and the environment.

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THE ENVIRONMENT AGENCYS ROLE (Cont.)

• They do this by
• advising on waste management methods including
  waste minimisation
• issuing Permits to waste operators providing
  satisfactory controls are in place
• site inspections and enforcement
• registering and monitoring people who transport
  waste
• working closely with other organisations to
  tackle specific issues such as fly-tipping
  (dumping waste illegally).

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THE ENVIRONMENT AGENCYS ROLE (Cont.)

• The EA carries out site inspections periodically
  to make sure that waste is recovered or disposed
  of in ways that do not harm the environment or
  cause damage to human health.
• If the Agency finds evidence that the environment
  or public health is placed at risk, they can take
  the action needed to prevent or reduce the risk.

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HOW DO WE DISPOSE OF WASTE?

• Around 70 of controlled waste in the UK is sent
  to landfill.
• The dots on the map indicate the location of
  active landfill sites in the UK.

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HOW DO WE DISPOSE OF WASTE?

• New legislation has recently been introduced in
  the UK.
• The EU Landfill Directive introduces some new
  requirements that will fundamentally change the
  way we manage waste in the UK Europe.
• It aims to classify landfill sites across the
  whole of Europe and to regulate them in a more
  coherent and consistent manner.

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HOW DO WE DISPOSE OF WASTE? (Cont.)

• Some new requirements
• introduced by the Directive include
• reducing the quantities of biodegradable
  municipal solid waste (MSW) sent to landfill
• banning the disposal of certain types of waste
  (clinical, liquid, explosive, corrosive,
  oxidising, flammable, highly flammable waste and
  tyres)
• treating most wastes before landfilling
• more prescriptive engineering standards.

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HOW DO WE DISPOSE OF WASTE? (Cont.)

• Some other ways of disposing of or minimising
  waste include
• Recycling
• Composting
• Incineration

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DISPOSAL OF WASTE TO LANDFILL

• An understanding of Geology is fundamental to the
  management of waste because
• Wastes and contaminants occur in and travel
  through the geologic environment so we need to
  understand
• the nature of this environment
• the transport processes
• most waste management schemes involve the use of
  geologic reservoirs for containment or the use of
  geologic process for dilution and dispersal of
  the waste

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WHAT IS A LANDFILL SITE?
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WHAT IS A LANDFILL SITE?

• A landfill site is a licensed facility where
  waste is deposited for permanent disposal.

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WHAT DOES A LANDFILL SITE LOOK LIKE?
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WHAT DOES A LANDFILL SITE LOOK LIKE?
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WHAT DOES A LANDFILL SITE LOOK LIKE?
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WHAT DOES A LANDFILL SITE LOOK LIKE?
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WHAT DOES A LANDFILL SITE LOOK LIKE?
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WHAT DOES A LANDFILL SITE LOOK LIKE?
Modern landfills are designed to confine the
waste to prevent it from causing environmental
or health problems.
Daily cover is placed over the compacted waste
each day to minimise infiltration of rainwater.
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WHAT PROBLEMS DO LANDFILL SITES POSE?

• Groundwater Contamination
• Production of Landfill Gas
• Landfill fires
• Offensive odours
• Litter
• Pests (Vermin, seagulls, flies)
• Increased traffic for duration of infilling
• Long term settlement after completion

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GROUNDWATER CONTAMINATION

• Groundwater contamination can occur if leachate
  leaks into the soils and rock surrounding a
  landfill site, eventually making its way to the
  water table and contaminating the groundwater.
• Leachate is formed when water percolates through
  solid waste.
• Leachate can be highly toxic.

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PRODUCTION OF LANDFILL GAS

• Landfill gas is produced during the natural
  breakdown of biodegradable waste.
• The composition of landfill gas changes over
  time.
• The gas from a typical landfill site consists
  mostly of methane and carbon dioxide.

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LANDFILL FIRES

• As waste decomposes it generates heat and
  underground fires may start.
• These are difficult to extinguish, may last for
  long periods, and may spread throughout the
  landfill.

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LANDFILL DESIGN

• Modern landfills are designed to minimise these
  problems
• Location
• Landfill Liner
• Compaction of waste
• Daily Cover
• Landfill Cap
• Leachate Management System
• Landfill Gas management System

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LANDFILL LOCATION

• In order to obtain a permit a landfill operator
  must first carry out a detailed investigation and
  prove to the satisfaction of the planning
  authority and the EA that the site
• is located in a geologically stable area
• is not located on a major aquifer
• Is not located in a vulnerable area
• is designed to reduce the risk of damage to the
  environment and human health
• will be monitored regularly for the duration of
  operations and aftercare period.

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Installation of monitoring/site investigation
borehole
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LANDFILL LINERS

• Landfill Liners are constructed on the base and
  sides of a landfill site to prevent leachate from
  leaking into the surrounding soils.
• Landfill Liners may be constructed from
• Compacted Clay
• Bentonite Enhanced Sand
• Geomembrane
• Geotextile Protector
• Dense Asphaltic Concrete (DAC)
• Combination of the above

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LANDFILL LINERS
Construction of compacted clay liner
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LANDFILL LINERS
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LANDFILL LINERS
Installation of Geomembrane Basal Liner
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LANDFILL LINERS
Construction of Dense Asphaltic Concrete
Liner This is a new method of lining landfills.
The first landfill to be constructed with this
type of lining system in the UK is North of
London and was completed this summer.
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LANDFILL LINERS
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CONSTRUCTION QUALITY ASSURANCE

• All construction carried out on landfill sites is
  supervised and recorded by an independent
  consultant.
• Following construction, certification reports are
  produced by the consultant and issued to the
  Environment Agency for approval.

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LANDFILL OPERATIONS

• 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

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LANDFILL OPERATIONS

• To prevent wastage and the formation of layers of
  weakness within the waste mass the daily cover is
  scraped off and re-used each day.
• Leachate that collects at the base of the waste
  mass is collected and re-circulated into the
  waste. This
• increases the rate of decomposition of the waste
  and therefore, rate of settlement
• decreases disposal costs.

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LANDFILL CAP

• Landfill caps placed above the waste after
  completion of infilling prevent the infiltration
  of rainwater, minimising the production of
  leachate.
• Landfill Caps are usually constructed from
• Recompacted clay
• Geomembrane

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LANDFILL CAP
Construction of geomembrane cap
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LANDFILL CAP
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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

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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
• active

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LANDFILL GAS MANAGEMENT SYSTEM

• Passive management systems comprise of wells with
  perforated tops to allow the gas to vent into the
  atmosphere
• Active management systems involve the active
  extraction of the gas.
• The extracted gas can be used to generate
  electricity.

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LANDFILL GAS MANAGEMENT SYSTEM
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LANDFILL GAS MANAGEMENT SYSTEM
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LANDFILL GAS MANAGEMENT SYSTEM
Electricity generating system
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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.
• Chemical testing is carried out regularly on
• Groundwater
• Leachate
• Landfill Gas

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SUMMARY

• Landfill sites are not very pleasant!
• BUT
• The negative effects can be minimised if
• they are designed carefully with due
  consideration of the geological and
  hydrogeological conditions
• construction works are supervised controlled by
  a qualified engineer
• they are carefully managed throughout their
  operational life and aftercare period.