Chapter 6.6 Land disposal
Notes on this chapter
Landfill is the most commonly practised waste disposal method in most countries for
most waste types, and is a fundamental requirement in all countries and all situations. For
that reason, this chapter is longer than others in this manual.
As a result of serious environmental problems associated with abandoned dump sites and
the high costs of clean-up measures to deal with contaminated sites, many countries have
introduced the concept of engineered landfill where wastes are directed to landfill sites
chosen on the basis of their containment capabilities.
The containment may be natural. Alternatively it may be augmented, or provided
directly, by liners. The overall aim of the engineering is to ensure as far as is possible the
isolation of wastes from the environment.
Landfill is considered a final resort, to be used for disposal only after every effort has
been made to avoid or reduce the hazards posed by the waste. Agenda 21 (Chapter 20)
stipulates that prevention of the generation of hazardous waste, and the rehabilitation of
contaminated sites, are key elements for environmentally sound management. Both
require experienced personnel, facilities, financial resources and technical capabilities.
Many countries starting to implement a hazardous waste management programme are
faced with the existence of unregulated dump sites. Where these sites are continuing to
operate, it is important to focus on immediate remedial measures and improvements. At
the same time, waste management strategies should be based on the concept of providing
long term security rather than short term expediency. The latter is inappropriate with
respect to hazardous waste landfilling.
Summary of slides
Title slide
Slide 2 Structure of chapter
Slide 3 Introduction: Current status of landfill
Slide 4 Risks of uncontrolled landfill
Slide 5 Risk mitigation
Slide 6 Uncontrolled landfill: landslip
Slide 7 Need to raise standards
Slide 8 Part A Key principles of a landfill site
Slide 9 Stages in improving landfills
Slide 10 Components of a well managed landfill operation
Slide 11 Choosing a site
Slide 12 Upgrading municipal landfill: site considerations
Slide 13 Siting a landfill: example
Slide 14 Site design – liner systems
TRP Chapter 6.6
1
Slide 15 Site design – liner materials
Slide 16 Cross section of multiple layer liner system
Slide 17 Site design - leachate control
Slide 18 Site design - landfill gas management
Slide 19 Site preparation
Slide 20 Site operation
Slide 21 Cellular structure
Slide 22 Waste compaction
Slide 23 Purpose of cover
Slide 24 Final cover
Slide 25 Completed landfill cross section
Slide 26 Part B Handling industrial wastes in municipal landfill as an interim solution –
Co-disposal
Slide 27 Basic requirements for co-disposal
Slide 28 Testing and record keeping
Slide 29 Compatibility of hazardous wastes
Slide 30 Co-disposal
Slide 31 Co-disposal - considerations and status
Slide 32 Wastes suitable for co-disposal
Slide 33 Co-disposal – maximum concentrations
Slide 34 Components of a well-managed co-disposal operation
Slide 35 Co-disposal site infrastructure 1
Slide 36 Co-disposal site infrastructure 2
Slide 37 Hazardous waste placement – practicalities
Slide 38 Co-disposal case study - asbestos waste
Slide 39 Part C Purpose-designed industrial waste landfill sites
Slide 40 Option 1: multi disposal
Slide 41 Wastes suitable for disposal in multi-disposal site
Slide 42 Multi-disposal site design
Slide 43 Multi-disposal site operation
Slide 44 Section through multi-disposal site
Slide 45 Option 2: Secure landfill of stabilised wastes
Slide 46 Basic principles of secure landfill of stabilised wastes
Slide 47 Adaptation of secure landfill of stabilised wastes
Slide 48 Option 3: The ‘ultimate’ landfill
Slide 49 Summary
Background notes
1 Land disposal includes several options including landfill, land spreading (see Chapter
6.3 Biological treatment) underground injection and deep mine storage (see Chapter 6.4
Stabilisation and solidification). This chapter looks at different methods of landfilling
hazardous wastes. Landfill is an inevitable part of a hazardous waste management system
in every country.
TRP Chapter 6.6
2
2 Each country has different priorities, constraints and drivers. A major driver for change
in developing economies may be public health and environmental concerns.
3 Modern landfill practices are constrained in some developing economies by a lack of
resources, both economic and human. Designing, constructing and operating landfill to
high standard requires a variety of skills, trained personnel and adequate funds.
4 It is important to adopt appropriate treatment and disposal methods for the local
circumstances, and to recognise the need for ‘fitness for purpose’. Affordability and
practicality must be considered, and for many countries landfill offers the best solution
for many hazardous wastes not least because of its flexibility and relative simplicity.
5 Upgrading from dumps to engineered sites is an important step towards an effective
hazardous waste management system. It will not be possible to meet basic environmental
standards without such sites. However, it is important to note that it has taken developed
countries many years to achieve uniform landfill standards. In the short term, developing
economies may have no alternative to putting industrial and commercial wastes in dump
sites.
6 Landfill sites have a life which extends from initial engineering and design through the
period of filling to a period many years after closure. Care must be taken to ensure that
environmental problems do not develop at any of these stages.
7 Once contamination results from badly managed hazardous waste sites, the problem of
dealing with it is enormous. For example, in the USA, more is spent on cleaning up past
contamination than is spent on disposal of current hazardous wastes, because of earlier
mismanagement.
8 This history of contaminated sites and recent high profile research into the effects of
living close to waste facilities has prompted questions about the long term health and
environmental impacts associated with landfill. As a result, siting new landfills is
increasingly difficult in every country.
9 Some of the opposition can be assuaged by sound site selection and engineering, and by
active public involvement in the decision-making process. (See Chapter 2.4 Public
communication and education)
10 Once constructed, the operation of the landfill is an important aspect of its
acceptability to neighbours. Cover regimes should be observed to limit vermin, litter
collected and drainage ditches kept clear. Good housekeeping measures of all kinds with
also improve site efficiency.
11 Site closure and aftercare are important. Good operation and waste compaction during
use will assist in the closure and re-vegetation of the site once closed, and reduce the risk
of problems. Monitoring of gas and leachate must continue for many years after the site is
full but this will be planned for at the site design stage.
TRP Chapter 6.6
3
12 After-use of the land depends on a number of factors, but if it is to be used for
agriculture tests must first ensure its suitability. Other possible uses include recreation,
forestry, industrial development and construction.
Sources of further information
Ball, JM Editor (1994) Minimum requirements for waste disposal by landfill Ministry of
Water Affairs and Forestry, South Africa – Waste Management Series (available from
www-dwaf.pwv.gov.za/documents/)
Batstone, R; Smith, JE & Wilson, DC editors (1989) The safe disposal of hazardous
wastes: The special needs and problems of developing countries World Bank,
Washington, Technical paper No 93 vol 3 ISBN 0-8213-1144-1 (available as pdf files
from www.worldbank.org/publications/)
Dean, RB & Wilson, DC (Editors) (1990) Adapting hazardous waste management to the
needs of developing countries, Waste Management & Research Vol 8 No 2
De Bruin, T (1990) Co-disposal and encapsulation Waste Management & Research Vol
8 No 2
Dept of Environment, Food & Rural Affairs (1997) Co-disposal Waste Management
Paper 26F (available from www.hmso.gov.uk)
Fourie, HO Editor (1994) Minimum requirements for the handling and disposal of
hazardous waste Ministry of Water Affairs and Forestry, South Africa – Waste
Management Series (available from www-dwaf.pwv.gov.za/documents/)
Guyer, Howard H (1998) Industrial processes and waste stream management Wiley
ISBN 0-4712-9984-7
LaGrega, MD; Buckingham, PL; Evans, JC & ERM Group (1994) Hazardous Waste
Management McGraw Hill, New York ISBN 0-07-019552-8
Rushbrook, P & Pugh, M (2000) Solid waste landfills in middle- and lower-income
countries: a technical guide to planning, design and operation World Bank, WHO and
Swiss Agency for Development & Co-operation ISBN 0-8213-4457-9
Savage, G; Diaz, L; Golueke, C; Martone, C & Ham, R (1998) Guidance for landfilling
waste in economically developing countries ISWA (available from
www.iswa.org/bookshop/)
Sloan, WM (1993) Site selection for new hazardous waste management facilities WHO
Regional Publications European Series No 46, Copenhagen ISBN 9-2890-1309-5
TRP Chapter 6.6
4
Thurgood, M Editor (2000) Decision-makers’ guide to solid waste landfills – Summary
World Bank, WHO and Swiss Agency for Development & Co-operation (available from
books@worldbank.org)
UNEP (1994) Hazardous waste landfill – a training manual Technical report No 17
UNEP Industry & Environment Programme Activity Centre & Environmental Education
& Training Unit, Paris ISBN 92-807-1384-1
USEPA (1989) Requirements for hazardous waste landfill design construction & closure
Center for Environmental Research EPA 625/4-89/022
World Bank (1991) Environmental Assessment Source Book Vol 1 World Bank
Technical paper No 139 ISBN 0-8213-1843-8
TRP Chapter 6.6
5