LANDFILL
Types of landfill
Milled solid waste
For individual waste constituents
Landfill Planning
commingled MSW
Limited amount of non-hazardous industrial waste and sludge from water and wastewater treatment plants are accepted
less soil and cover is used because it can be compacted
native soil is used as intermediated and final cover material
to obtain additional LF capacity, abandoned or closed landfills can be reused to recover materials and using decomposed residue as dily recover
if not available, compost, foam, old rugs and carpeting waste can be used
need more shredding facilities, special section for hard shredded wastes
potential application in areas where landfills capacity is very expensive, cover material not readily available and low precipitation
shredded waste can be used to produce compost which can be used as intermediate cover material
no need cover material
combustion ash and asbestos identified as designated wastes
to isolate from materials placed in MSW LF
combustion ash monofill may have odor due to reduction of sulfate-gas recovery system is recommended
Sitting consideration
Layout and design
Operations and management
Reactions occuring in landfill
Available land area
Haul distance
Soil conditions and topography
surface water hydrology
site selection
site rating process
identification of site areas
site investigation
Final decision
drinking water protection area
high flood area
unstable ground
volume, distance from main waste source
hydrogeology and water management
meteorological aspects
Site construction requirement
Protection of soil and water
Location
operations
costs
capacity of the waste
stability
density of wastes
amount of daily cover
amount of settlement
compacted to reduce the volume
confined to small area
covered with layer of soil
installation of liner and collection system
storm water control
leachate management
easy access
land value
location of community served
feasibility studies
site after care
site investigations
underlying geology
water table
location nearby rivers, stream and flood plains
Landfilling methods
Trench method
suit with area with adequate depth of cover material is available at site and deep water table
wastes placed in cell excavated in soil
cell line with synthethic membrane liners or low permeability clay
Canyon/Depression method
critical factor-control of surgace drainage
key of success is availability of adequate material to cover individual lifts and final cover
filling for each lifts starts at the head end of canyon and ends of mouth
Factors to be considered in construction
minimum dimension required for construction work
simple and non sensitive design and construction
climate conditions
availability of construction materials
Leachate Management Facilties
landfill liner and and leachate collection facilities
Leachate Treatment Facilities
Type of landfill liner used is depend on local geology and hydrology
landfill site should be located where there is little or no possibility of contaminating potable water supplies
curent trend is using composite liners including a geomembrane and clay layer
Leachate recycling
Leachate evaporation
treatment followed by disposal
discharge to municpal wastewater collection system
Construction Phase
Phase 1-Excavate land to within 3 feet of the top of water table
Phase 2-Add compacted clay layer or synthetic liner
Phase 3- Install leacharte collection system
Phase 4 -install geosynthetic liner to stabilize the waste
Phase 5- add a slope, sand drainage liner to drain liquid away from waste into the leachate collection system
Phase 6- Deposit solid waste
Phase 8-Add soil layer
Phase 7- Install groundwater and gas monitoring wells
Phase 9- Install clay cap
Phase 10- Install geosynthetic cap
Phase 11-Install sand drainage layer
Phase 12- Add a layer of top soil to promote plant growth
Phase 13- plant grass and other short rooted plants to prevent erosion of landfill surface
Phase 14-construct methane recovery building
Selection of gas control facilities
new lanfdills are required to have gas collection and treatment facilities
quantity of LFG must be first esimated before determining the size of gas collection and treatment facilities
Landfill operatinos- factors to be considered
waste placement techniques
operating facility
gas managment and monitoring programs
Landfill gas management
a product of degradation of biodegradable waste
evolution rate and quantity of landfill gas depend on these factors
waste input rate
ambient pH
ambient temperature
waste density
divided into
passive gas collection system
active gas collection system
Odour control technologies
landfill cover
flaring
venting