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Technical Lecture
toFinal Year Bachelor of Civil and Urban Engineering
Department of Environmental Engineering
An Introduction to Sanitary Landfill
- A Viable Solution for
Existing Solid Waste Management
Practices in Karachi Metropolis
Dr. Mansoor Imam
Associate Professor, Department of Civil Engineering,
NED University of Engineering and Technology, Karachi
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Solid Waste Management (SWM)System
Community Based
Organisations CBOs
and other operators
(private contractors,
sweepers etc)
CollectionD
TransportationD
DisposalHierarchy of Solid Waste Management
Town
Councils
Union
Councils
Collect & Transport waste from
designated locations to disposal
sites
Collect & transfer waste from
community bins to designated
locations within the Town
jurisdiction
Formal
Informal
Collect from
streets/houses/public places
and transfer to Community
Bins Kachra Kundis
Recovery
&
Recycling
Recovery
&
Recycling
Recovery
&
Recycling
Recovery
&
Recycling
Recovery
&
Recycling
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Solid Waste Management by Informal Sector
Recovery of recyclable material from waste at various levels
Household Kabadis
Level Operator Activity
Door-to-door collection of
recyclable items; Paper,
Glass, Metal, Plastic, etc.
Street Scavengers or
waste pickersWandering in the streets and
hand-picking recyclable items Community bin
Disposal site Potters,
Contractors,
etc.
Rich organic waste is
burnt as fuel forkilns,
and metal recovery.
Dried waste forfills
Waste Recovery = 12%
Waste Recovery = 11%
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Separated at household and sold toKabadis 800 tons/day
Collected by waste pickers or scavengers 700 tons/day
Waste utilisation prior to final Disposal 750 tons/day
Estimates of Solid Waste Managed (Pre-Devolution) by
Formal and Informal Sector
Formal Sector
Managed by Metropolitan services 2,200 tons/day
Informal Sector
Unmanaged / uncollected Solid Waste 2,150 tons/day
Total Estimated Solid Waste generated 6,600 tons/day
33%
33%
33%
Source: Urban Resource Centre
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Changing Perspectives ofChanging Perspectives ofSolid Waste ManagementSolid Waste Management
Approx. 50,000 tons of solid waste is generated per day in Pakistan
~20,000 tons arises from Urban areas
~30,000 tons from Rural areas Source: NCS
Present coverage of Urban Solid Waste Management is 25%
and then to 90% by 2025
shall increase to 55% by 2010-11
US$ 25 million has been allocated for the improvement ofSWM System
Environmental Strategy 2002: IUCN
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Safe Disposal of Solid Waste most critical aspect of SWM
Open Dumping sitesUncontrolled tipping
Informal
Drains / Nalas
Empty Plots
Natural Depressions
Formal
Reclamation of land
Sanitary Landfill or Open Dumping ???
Concept ofSanitary Landfill is virtually non-existing
Sanitary Landfill sites are open dumping grounds
Jam Chakro (500 acres) Gond Pass (500 acres)
1000 tons/day 500 tons/day
Dhabeji (remote site) non operational
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Introduction to Sanitary Landfill
Landfillan engineered facility developed on a designated piece ofland that principally receives waste as a fillover a period of time until
the designated area is fully utilised. The development and operation at
the facility is usually costeffective while maintaining appropriate health,
safety andenvironmental standards.
Landfill Methods
Excavated cell or trench method Area method
Canyon or depression method
Selection of method depends upon:
Geographical features
Geohydrological characteristics
Economic constraints; Operational limitations; Post-closure use; etc.
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Development of Landfill Facility
Selection of site for Landfill
When selecting a site for landfill, following considerations are made:
Haul distance
Location restrictions
Available land area
Site accessibility
Soil conditions and Topography
Climatologic conditions
Surface water hydrology
Geologic and Geohydrologic conditions
Environmental impact of landfill site
Potential post closure use
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Establishing Design Criteria
Waste characteristics &
Quantity Operational & Design lifeD
Infiltration
Surface Water drainage
Disposal of Leachate
Production ofGas
Daily Cover design (material)
Final Cover Liner system
Leachate management system
Gas Collection & Recovery system
D
Post closure Monitoring (Leachate and Gas)
Future use and development
Facilities Development Infrastructure, Utilities & ServicesD
D
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Collection of Necessary Data for Design of Landfill
Hydrogeologic investigation
Geologic Stratigraphy
Groundwater depths and flow directions
Soil investigation Characteristics of local soil(s)
Topography and Contour mapping
Climatologic data Precipitation, Temperature,Humidity, Wind pattern, etc.
Physical data of site layout, boundary demarcation and vicinity land-use
Geotechnical investigation
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Typical components of a Sanitary Landfill
Liner system (A)
Cap system (B)
Gas management system (C)
Leachate management system (D)
Erosion & Sedimentation control
Surface water management (E)
Monitoring system (F)
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6 Topsoil
ayer
24"
arrier
rotection
ayer
Geomembrane
18"
lay
ayer
12" Gas Venting
ayer
Solid Waste(variousthickness)
24"
rimary
eachate
ollection
emoval System
Geomembrane
6"
lay
ayer or G
12" Structural
ill
12" Secondary
eachate
ollection System
Geomembrane
24"
lay 24 thick lay layer
12 thick pervious layer Secondary eachate collection
12 thick Structural fill compacted for stability
24 thick pervious layer rimary eachate collection
Solid waste
compacted in layers
(cell lift)
12 thick Gas Venting layer
Geomembrane
Geomembrane
18 thick lay layer
24 thick arrier protection layer
6 thick Topsoil layer
Geomembrane
overSystem
Waste mass
inerSystem
Typical section of a
Sanitary Landfill
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Preparation of Design Document
Design and Plans for Landfill Operations
Revision of plans according to the progress of work
Plans & specifications for Landfill system components
Preparation of Development,
Operations & Maintenance
plan
Infrastructure Development at Landfill site
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Conclusions and Recommendations
A properSanitary Landfill is the only option forsafe disposal ofsolid waste generated in Karachi Metropolis and must be developed
on priority basis.
Though the available waste management infrastructure is inadequate
to support and sustain proper sanitary landfill facility, howeverinvolvement
of private sector may provide a sustainable solution.
It would be appropriate to have more than one easily manageable
landfill sites located in vicinity of urban settlements rather than one
large facility remotely situated.
Integration of informal sector within the formal sector may
improve, managing waste efficiently. The active role of informal sector
in managing the waste should therefore, be recognised and promoted by
the civic administration.