L3

Question 1

Describe a risk based landfill design

Answer 1

Risk = source/ pathway/ receptor

• source
  > waste composition
  > leachate composition
  > Gas composition
• pathway
• receptor
  > sensitive ground water resource
  > rivers
  > wider environment

Question 2

what is the historical perspective of landfills?

Answer 2

• the deposit of poisonous waste act 1972
• the control of pollution act 1974
• EU waste framework directive 1975
• the ground water directive 1979
• special waste regulations 1980
• the collection and disposal of waste regulations 1988
• hazardous waste directive 1978
• environmental protection act 1990
• controlled waste regulations 1992
• waste management licensing regulations 1944
• environment act 1995

Question 3

historical perspective 2

Answer 3

IPCC directive 1996
ground water regs 1998
human rights act 1998
landfill directive 1999
EIA regs 1999
Pollution prevention and control act 1999
pollution prevention and control regulations 2000
water framework directive 2000
Landfill (England and wales) regs 2002 
Hazardous waste regulations 2003
waste management licensing amendments regs 2003
groundwater directive 2003
groundwater regulations regs amendment

Question 4

describe the landfill directive

Answer 4

EU landfill directive (LFD) implemented on 16th July 2001

aim: to improve standards and reduce negative effects on:
- environment: groundwater, surface water, soil, air
- global environment including greenhouse effect
- risks to human health

> encourage a level playing field across Europe
reduce overall reliance on landfill as a waste disposal option

Question 5

what does the LFD affect?

Answer 5

applies to all landfill sites which accept waste on or after 16 July 2001

• existing landfills had a transitional period within which to comply with the LFD, but must comply with certain aspects by set dates, and all by July 2007
• existing sites must apply for PPC permit, highest risk first (April 2003), all by 2007
• new sites must comply from start

Question 6

what is the directive requirement?

Answer 6

1. classification of sites as hazardous, non-hazardous and inert
2. prevent co-disposal of hazardous wastes with other wastes from july 2004
3. ban on the disposal of certain wastes to landfill e.g. tyres, liquid wastes, explosive, corrosive, oxidizing, highly flammable and flammable wastes
4. reduction in the amount of biodegradable waste going to landfill (article 5)

Question 7

Directive requirement (2)

Answer 7

treatment of waste prior to landfill from 2004
- physical, thermal, chemical or biological processes, including sorting to change characteristics
> reduce volume or hazardous nature
> facilitate handling
> enhance recovery

Waste acceptance procedures from 2004

Question 8

Directive requirement 3

Answer 8

engineering design based on risk assessment (groundwater, landfill gas, stability)

• the use of landfill gas where possible
• specific closure and aftercare procedures

Monitoring
- groundwater control and compliance

• financial provision required for all landfills sites

Question 9

describe environmental permitting regulations (2010)

Answer 9

the classification of all substances as hazardous or non-hazardous is relevant in all cases where regulation of an input of pollutants to groundwater (a groundwater activity) is required by the EPR 2010

• hazardous substances must be prevented from entering groundwater
• a non-hazardous pollutant is defined in environmental permitting regulations 2010

Question 10

main groundwater and surface water use

Answer 10

ground
Southern
Anglian
midland

surface

• south west
• wales
• northwest
• thames
• Anglian

Question 11

what do the environmental permits entail

Answer 11

• a description of the facility
• management
• permitted activities
• site
• operating techniques
• improvement and pre-operational conditions
• engineering
• waste acceptance
• emission control
• monitoring
• reporting

Question 12

what is LandSim v2.5

Answer 12

tool to asses risks to groundwater from landfills

• use to optimize engineering design and operations
• if conceptual model appropriate for site, angency preferred risk assessment tool
• probabilistic (Monte Carlo) model to allow range of input values by defining probability densty functions (PDFs)

Question 13

what does a simple conceptual model entail>

Answer 13

• waste
• leachate collection
• liner (none, clay, HDPE, double composite liner and geosynthetic clay liner (GCL))
• vertical flow through unsaturated zone (must be above the water table)
• dilution in saturated zone
• attenuation in each layer
  > retardation (Kd)
  > biodegradation
  > dispersion
• background water quality can be taken into account
• multiple phases and landfill sites are possible
• biodegradation of organic contaminants is allowed
• receptor allowed for each phase plus elevation of the combined effect of all phases on a user-defined receptor
• calculates contaminant concentrations at the base of the unsaturated zone (use for List 1)

Question 14

Sub-water table (hydraulic contaminant) landfills

Answer 14

• contaminant fluxes from hydraulic contaminant landfills- a review
  > hydraulic contaminant (theory and practice)
  > diffusion across liners (clay and geomembrane)
• three conceptual models for existing/ new sites
• spreadsheet tool to calculate:
• diffusive contaminant fluxes from hydraulis contaminant landfills
• contaminant concentrations in groundwater (or pore water at the base of the liner for list 1 substances
• includes diffusion, dispersion, retardation, and decay processes
• indicative values for key parameters