A landfill site, also known as a tip, dump, rubbish dump, garbage dump, or dumping ground, is a site for the disposal of waste materials. Landfill is the oldest and most common form of waste disposal, although the systematic burial of the waste with daily, intermediate and final covers only began in the 1940s. In the past, refuse was simply left in piles or thrown into pits; in archeology this is known as a midden. Some landfill sites are used for waste management purposes, such as temporary storage, consolidation and transfer, or for various stages of processing waste material, such as sorting, treatment, or recycling. Unless they are stabilized, landfills may undergo severe shaking or soil liquefaction of the ground during an earthquake. Once full the area over a landfill site may be reclaimed for other uses.

1. INTRODUCTION TO
SCIENTIFIC LANDFILL
C.E 8.3.2
Unit III
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 1

2. WHAT IS A LANDFILL?
An engineered site where waste is
isolated from the environment
below the ground or on top until it
is safe and completely degraded
biologically, chemically and
physically.
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 2

3. DIFFERENCE BETWEEN OPEN
DUMP AND LANDFILL
A dump is an open hole in the ground where
trash is buried and where animals often
swarm. They offer no environmental
protection and are not regulated.
A landfill is a carefully designed and
monitored structure that isolates trash from
the surrounding environment (e.g.,
groundwater, air, rain). This isolation is
accomplished with the use of a bottom liner
and daily covering of soil.
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 3

4. WHY LANDFILLS
ARE
IMPORTANT..????
i. To prevent contamination of waste into the surrounding environment, especially
groundwater due to open dumping.
ii. Some materials can not be recycled, used for energy or composted.
iii. Increasing population resulting in increase in waste
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 4

5. WHAT HAPPENS TO THE WASTE IN
LANDFILL…???
i. Designed to bury waste in layers of soil
ii. Compacting the layers to reduce volume
iii. Slowdown of waste decomposition with minimal amounts of oxygen and moisture
iv. Finally covering them with soil each day so as to minimize human health and
environmental problems.
v. And for careful filling, monitoring and maintenance while they are active and for up to 30
years after they are closed
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 5

6. REACTIONS OCCURRING IN
LANDFILL
i. Biological – Aerobic and Anaerobic
Decomposition
ii. Chemical – Dissolution, Evaporation,
Adsorption, Decomposition, Oxidation,
Reduction
iii. Physical – Movement and settlement of
leachate and gas
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 6

7. LANDFILL – DESIGN AND
OPERATION
Planning phase - involves Preliminary hydro-geological and geo-technical site investigations as
a basis for actual design.
Construction phase - involves Earthwork, road and facility construction and preparation (liners,
drains) of the fill area.
Operation Phase (5-20 years) –
i. Involves work at the front of the fill area
ii. Completion of finished sections
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 7

8. LANDFILL – DESIGN AND
OPERATION
Completed phase (20- 100 years)
i. Emissions may have decreased to a level where they do not need any further treatment and
can be discharged freely into the surroundings.
Final storage phase
i. In this phase the landfill is integrated into the surroundings for the further purpose, no
longer needs special attention.
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 8

9. CROSS SECTION OF A
LANDFILL
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 9

10. COMPONENTS
OF A LANDFILL
Landfill cell: A hole in the ground that is
engineered and designed to protect the soil
and water supply from waste that is put in
the space.
Compacted clay liner (Secondary/
Impervious Liner):
i. When clay is pressed tightly together
it gets firm and doesn't let moisture
run through it easily.
ii. The liner holds the waste inside the
landfill and stops it from leaking into
the ground.
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 10

11. COMPONENTS
OF A LANDFILL
Geotextile (Secondary Liner/Impervious):
i. A fabric material laid to protect the
clay liner.
Gravel layer (Leachate Detection
Systems):
i. Crushed rocks and stones create
support for leachate pipes.
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 11

12. COMPONENTS
OF A LANDFILL
Leachate collection pipe:
i. Pipes at the bottom of the cell collect
leachate as it trickles down and help
move it out of the landfill.
Leachate pump station:
i. Leachate that is collected from the
leachate collection pipes goes to a
pump station, then it moves to the
sanitary sewer and then to the local
wastewater treatment plant for
cleaning.
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 12

13. COMPONENTS
OF A LANDFILL
Secure Landfill Garbage, recyclables and
organics (food) that get put into the
landfill.
Gas collection trenches: A group of
horizontal pipes laid on each layer of
waste within the cell that collect gas and
move it into gas wells.
Gas collection wells: Large pipes that
have more storage space to collect gas
from the trenches and then moves it to the
gas plant.
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 13

14. COMPONENTS
OF A LANDFILL
Clay cover: This clay cover is added to the
top of the landfill cell to close it.
Topsoil: Soil that is placed on top of the
clay cover to help vegetation grow.
Vegetation: Trees, grass, plants, bushes
and shrubs are planted all over the closed
landfill cell to make it part of the natural
environment
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 14

15. LANDFILL CLASSIFICATION,
TYPES AND METHODS
I. Sanitary Landfills - landfill that uses a clay liner to isolate the trash from the environment
Municipal solid waste (MSW) landfills - uses a synthetic (plastic) liner to isolate the trash
from the environment
II. Construction and demolition waste landfills - consist of the debris generated during the
construction, renovation, and demolition of buildings, roads, and bridges.
III. Industrial Waste Landfills- consists of nonhazardous waste associated with manufacturing
and other industrial activities
IV. Secure Landfills - landfills for the disposal of hazardous waste. Landfill Classification,
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 15

16. LANDFILL CLASSIFICATION,
TYPES AND METHODS
Classification:
I. Class I – for solid Hazardous waste only
II. Class II – for solid non – hazardous waste only
III. Class III - for inert waste only
IV. LF for commingled MSW
V. LF for shredded SW
VI. LF for individual waste constitutes/monofills (designated waste)
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 16

17. LANDFILL CLASSIFICATION,
TYPES AND METHODS
Trench Method (Below Ground Level)
i. Used where adequate cover material is available at site
and the water table is well below the surface.
ii. Waste are placed in trench and compacted in thin
layers.
iii. After layer’s compacted height reaches design height,
cover material is placed over the compacted layer.
iv. Same trench is then continued and filled similarly.
v. Good in areas where there is relatively little Waste.
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 17

18. LANDFILL CLASSIFICATION,
TYPES AND METHODS
Area Method (Above Ground level)
i. Used on flat ground or terrain is unsuitable for the
excavation of trenches.
ii. Before actual land filling, an earthen levee is
constructed against which wastes are placed in thin
layers and compacted.
iii. Thickness of layer reaches a height of 200 to 300 cm.
iv. Cover material of 15 to 30 cm thickness is placed after
each layer.
v. A completed lift including the cover is called a cell.
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 18

19. LANDFILL CLASSIFICATION,
TYPES AND METHODS
Depression/Valley Method:
i. Used where natural or artificial depressions exist and these are used for land filling.
ii. Depends on the geometry of the site, hydrology and geology of the site, and access to site.
iii. The normal practice is to place such that water does not accumulate behind the landfill.
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 19

20. LANDFILL CLASSIFICATION,
TYPES AND METHODS
Slope Method
i. In hilly regions it is usually not possible to find flat ground for land filling.
ii. Waste is placed along the sides of existing hill slope.
iii. Control of inflowing water from hill side slopes is a critical factor in design of such landfills.
Ramp Method
i. Used in the case of flat or slightly undulating areas.
ii. Modification of both the area and the trench method and utilizes certain technique of both
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 20

21. CRITERIA FOR SITE SELECTION
Potential landfill site is selected on the basis of
i. Responsibility of Development Authorities to identify the landfill sites and hand over the
sites to the concerned municipal authority for development, operation and maintenance.
ii. Near by waste processing facility.
iii. Soil Conditions and topography
iv. Surface water Hydrology
v. Large enough to last for 20-25 years.
vi. A buffer zone of no-development shall be maintained around landfill site.
vii. Temporary storage facility for solid waste shall be established in each landfill site.
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 21

22. TYPICAL RESTRICTIONS TO BE
OBSERVED
Distance Parameters Lake or pond
i. Max distance 200 m
ii. Water monitoring system should be installed if a landfill is sited less than 200 m of a lake
or pond.
iii. Sites falling within wetlands are avoided.
River
i. Max distance 100 m
ii. The distance may be reduced in some instance for non-meandering rivers but a minimum
of 30 m should be maintained.
iii. No landfill should be constructed within a 100 year-flood plain.
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 22

23. TYPICAL RESTRICTIONS TO BE
OBSERVED
Highway
i. Max distance 200 m
Habitation
i. Max distance 200 m of a notified habituated area.
ii. Sites falling within forest areas and national parks are avoided
iii. A distance of 100 m must maintained from the residential areas.
Public parks
i. Max distance 200 m
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 23

24. TYPICAL RESTRICTIONS TO BE
OBSERVED
Ground water table
i. No landfill should be constructed in areas where water table is less than 2 m below ground
surface.
Airport
i. A distance of 20 km from nearby airport must be maintained.
ii. Can set up between 10 km – 20 km by obtaining NOC from the civil aviation authority/ Air
force
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 24

25. LANDFILL LEACHATE
i. During landfill site operation, a liquid known as leachate is produced.
ii. It is a mixture of organic degradation products, liquid waste and rain water.
iii. It has high organic carbon content, high concentrations of nitrogen and is usually slightly
acidic.
iv. When the growth of a landfill is at its maximum capacity, landfill covers are installed.
v. Once covered, gases are directed to a flare and/or vents.
vi. This reduction of leachate and treatment is a definite cost savings
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 25

26. LEACHATE PROBLEMS
i. They clog up from silt or mud
ii. They can clog up because of growth of microorganisms in the pipes
iii. They can clog up because of a chemical reaction leading to the precipitation of minerals in
the pipes
iv. The pipes become weakened by chemical attack (acids, solvents, oxidizing agents, or
corrosion) and may then be crushed by the tons of garbage piled on them.
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 26

27. GASSES FOUND IN LANDFILLS
i. The typical constituents of gases produced by a municipal solid waste landfill:
ii. Component Percent (dry volume basis)
Methane 40-60% It is often flammable and sometimes even explosive
Carbon Dioxide 40-60% Non harmful to the environment
Nitrogen 2-5% Non harmful to the environment
Ammonia 0.1-1.0% Ammonia in air is an irritant and causes burning of the eyes,
nose, throat and lungs
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 27

28. ENVIRONMENTAL CONCERNS AND
REQUIREMENTS
Concerns:
 Availability of Land
 Uncontrolled release of gases
 Uncontrolled release of leachate
 Disease vectors breeding
 Ground water contamination
 Bird Menace
 Odour Environmental Concerns
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 28

29. ENVIRONMENTAL CONCERNS AND
REQUIREMENTS
Requirements
 ONLY for non-biodegradable, inert waste and other waste that are not suitable either for
recycling or for biological processing
 Residues of waste processing facilities
 Avoid landfilling mixed waste
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 29

30. ADVANTAGES OF LANDFILLING
i. Burying can produce energy by the conversion of landfill gas i.e. methane & CO2
ii. Byproducts can be used as direct/ indirect fuel for combustion.
iii. Easy Monitoring due to specific location
iv. Can be reclaimed and it can be used as parks or farming land.
v. All recyclable materials can be used before closing.
vi. Organic material can also be separated and used for compost or production of natural gas.
vii. Relatively Cheap
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 30

31. DISADVANTAGES OF
LANDFILLING
i. Problems faced when poorly designed or operated.
ii. Areas surrounding the landfills become heavily polluted.
iii. Dangerous chemicals can seep into the ground water system.
iv. Many insects and rodents are attracted to landfills and can result in dangerous diseases.
ASST. PROF. PRACHI DESAI, DON BOSCO COLLEGE OF ENGINEERING 31