WASTE TREATMENT AND DISPOSAL

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WASTE TREATMENT AND DISPOSAL
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Waste Treatment and disposal

• ideally the disposal methods should meet the
  following condition
• environment friendly
• cause no health hazard
• economically less demanding
• maximum recycling options
• Should not be labour intensive

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Waste Treatment

• The treatment of solid waste prior to disposal
  includes
• recycling
• compaction
• pulverisation

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Waste disposal

• ideally the disposal methods should meet the
  following condition
• environment friendly
• cause no health hazard
• economically less demanding
• maximum recycling options
• Should not be labour intensive

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• Disposal without treatment
• dumping in water
• dumping on land
• direct disposal (sanitary land field)
• Disposal involve some treatment
• incineration
• biological treatment
• pyrolysis

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DUMPING ON LAND
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Disposal On Land

• Landfill method
• Define as the physical facilities use for the
  disposal of residual in the surface soils of the
  earth.
• Sanitary landfill refer to engineered facilities
  for the disposal of SWM designed and operated to
  minimize the public health and environmental
  impacts

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• One of the primary technologies use to disposal
  of solid waste.
• The most economically if suitable land is
  available at low cost, environmentally accepted
  method and simple.
• The only method that can deal with all material
  in solid waste
• Direct disposal without treatment and Also used
  for the final disposal of treated waste.

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• Sanitary Landfill
• Define as
• Method of disposing refuse on land without
  creating nuisance or hazard to public health
• or safety by utilizing the principle of
  engineering to confine the refuse to the smallest
  practical area
• The goal for design and operation of modern
  landfill is to eliminate/ minimize the impacts to
  human and environment

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• and to reduce it to the smallest practical
  volume and cover it with a layer of earth at the
  conclusion of each days or at such more frequent
  as many be necessary
• also call as control tipping and involves the
  covering of the waste daily with soil or other
  modern material
• consist depositing the wastes in 1 -2 m tick
  layer in low-laying lands or excavation

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Landfill Planning, Design and operation

• The element s should be consider in the planning
  , design and operation of landfill are as below
• Landfill layout and design
• Landfill operations and management
• The reaction occurring in the landfill
• The management of leachate
• Environmental monitoring
• Landfill closure

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Landfill siting consideration

• Siting of new landfill is one of the difficult
  tasks faced by the most communities.
• Several factors must be consider in evaluating
  potential site for-long term disposal of solid
  waste.
• Final selection of a disposal site usually is
  best on the result of a detail site survey,
  engineering design, cost study and EIA.

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• The factors should be consider are
• Haul distance
• Location restriction
• Available land area
• Site access
• Soil condition and topography
• Climatological conditions
• Surface water hydrology
• Geologic and hydrogeologic conditions
• Local environmental conditions
• Potential ultimate uses for the completed site

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Preparation of the site

• First Step
• Existing site drainage must be modified to route
  any runoff away from the landfill area.
• Drainage of the landfill area itself must be
  modified to route water away from the initial
  fill area
• Construction of access roads, weighing facilities
  and fences installation.

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• Second Step
• The excavation and preparation of the landfill
  bottom and sub surface site
• Modern landfills are constructed in sections
  allows only the small part of the unprotected
  landfill surface to be expose to precipitation.
• Excavations are carried out over time not
  prepare the landfill bottom at once
• Excavated material can be stockpiled on
  unexcavated soil to minimized the precipitation
  problem

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• If the bottom of the landfill is lined at once,
  the storm water runoff must be remove from the
  portion of the landfill that is not being used.
• To minimized cost, it desirable to obtain the
  cover material from the landfill site whenever
  possible.
• The excavated material stockpiled for later use.
• Vadose zone and groundwater monitoring equipment
  is installed before the landfill liner is laid
  down.

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• Leachate collection and extraction faciliteis are
  place within or on top of the liner
• Usually the liner extends up the excavated wall
  of landfill.
• Installation of the horizontal gas recover
  trenches at the bottom of the landfill
• To minimized the release of VOCs, vacuum is
  applied and air is drown through the completed
  portion of landfill
• The gas that is remove must be burned under
  controlled condition to destroy the VOCs

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• A soil berm must be constructed at the downwind
  side of the planned fill area before the fill
  operation begin.
• Foe the excavated landfill, the wall of the
  excavation usually served as the initial
  compaction face.

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The placement of waste

• The waste is placed in cell beginning along the
  compaction face
• The waste deposited in each operating period
  usually one day from in an individual cell.
• Wastes deposited are spread out in 45 60 cm
  layers and compacted
• Typically the cell height vary from 2.8 4 metres

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• The length of the working face varies with the
  site condition the size of the operation
• The width of the a cell varies from 300 -900 cm
  depending on the design and capacity of of the
  landfill.
• The exposed faces of the cell are covered with a
  thin layer of soil (15 to 30 cm) at the end of
  each operating period.
• After or more lifts has be place, horizontal gas
  recovery trenches can be excavated in the
  completed space.

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• The excavated trenches are filled with gravel and
  perforated plastic pipes are installed in the
  trenches
• Successive lifts are place on top of another
  until the final design grade is reached.
• A cover layer is applied to the completed
  landfill section to
• minimized infiltration of precipitation
• to route drainage away from the active section of
  the landfill
• The landscaping to control erosion

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Reactions in landfill

• Biological reactions
• The organic material in MSW lead to the
  production of landfill gas and liquids.
• Decomposition process usually proceed aerobically
  for a short period.
• During aerobic decomposition, CO2 is the gas
  produced
• Once the available O2 has been consumed, the
  composition become anaerobic and the organic
  matter converted to CO2 and CH4 and ammonia and
  hydrogen Sulfide.

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• Chemical Reaction
• Include dissolution and suspension of landfill
  materials and biological conversion products in
  the liquid percolating, evaporation and
  vaporization of chemical compound and water
• The organic compounds can subsequently be
  released into the atmosphere through the soil
  or from uncover leachate treatment facilitie.
• Other chemical reactions include those between
  certain organic compound and clay liner.

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• Physical reactions
• The important physical changes are
• the lateral diffusion of gases and emission of
  landfill gases to surrounding environment
• Movement of leachate within the landfill and into
  underlying soil
• Settlement caused by consolidation and
  decomposition of landfill material
• Landfill gas movement and emission particularly
  important consideration in landfill management
  because

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• Internal pressure could causing the landfill
  cover crack and leak
• Escaping landfill gas may carry trace
  carcinogenic and teratogenic compounds into the
  environment
• Because high CH4 contents, may be can cause
  burning or explosion
• Leachate migration is another concern

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Concerns with the landfill

• Uncontrolled release of landfill gas
• The impact of uncontrolled discharge of landfill
  gas
• Uncontrolled release of leachate
• The breeding of disease vector
• The health and the environmental impact

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SANITARY LANDFILL FACILITIES
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