1. Disposal and Containmant Techniques

3. Selection of sites for Waste Disposal facilities
Receptor related attributes
Population with in 500 m
Distance to nearest drinking well
Use of site by nearby residents
Distance to nearest office building
Land use
Critical Environment

4. 2. Pathway related Attributes
Distance to nearest surface water
Depth to ground water
Type of contamination
Precipitation
Soil permeability
Bed Rock Permeability
Depth to bed rock
Susceptability to erosion and runoff
Climatic factors relating to air pollution
Susceptibility to seismic activity

5. 3.Waste and related attributes
Toxicity
Radioactivity
Ignitability
Reactivity
Corrosivity
Solubility
Volatility

6. 4.Waste Management related attributes
Physical state
Waste quantity
Waste compatibility
Use of liners
Gas Treatment
Leachate Treatment
Site security
Safety measures

7. Siting criteria

8. Site investigation criteria
Sub Soil Investigation: type of soil, depth of GWT and bedrock, permeability of various strata, strength parameters, extent of availability of liner materials
Ground Water / Hydro geological Investigation: Depth of GWT, GW flow direction, Baseline GW quality parameters
Topographical Investigation: To compute the earth work quantities precisely
Hydrological Investigation: To estimate the quantities of runoff for appropriate design of drainage facilities
Geological Investigation and Seismic Investigation: to delineate the bedrock profile beneath the landfill base

9. Criteria
subcriteria
Significance
Soil
Permeability
Release of pollutants- Low permeability required pH
Tendency of soil to aborb heavy metals- high pH
Cation exchange capacity
Ability of soil to attenuate some contaminats- High cation exchange
Surficial soil
Affect degree of attenuation-surficial soil with low permeability

10. Criteria
subcriteria
Significance
Geology
Bedcrop and outcropping
Carbonate rocks susceptible to solution
Fractured rock-pollution migration
Mass permeability
Control migration of contaminants
Faults
Release of pollution

11. Criteria
subcriteria
Significance
Ground water
Aquifer
With low potential use preferred
Ground water quality
Poor groundwater quality- best suitable location
Ground flow system
Sites where direction of GW flow away or flow is upward

12. Criteria
subcriteria
Significance
Monitoring aspects
Sites that are easy to monitor
Slope
Slope of ground
Slopes greater than 15% or 22% is preffered

13. Criteria
subcriteria
Significance
Topography
Slope erodibility
runoff
Slow runoff ares preffered

14. Hydrogeological aspects of selection of waste disposal sites
CONDITIONS AT THE SITE
PROVISION OF DATA FOR DESIGN AND MANAGEMENT OF WASTE DISPOSAL FACILITIES

15. Assessment of regional and local geology
Assessment of local surface hydrology
Identification of main hydrogeological units (aquifers,aquiclude etc)
Ground water mechanisms
Local structural features
Measuring GWL and hyraulic gradient
Estimating hydraulic conductivity
Ground water chemistry
Surface and ground water receptors of contamination
Present and future development of GW
Characteristics of materials present in saturated and unsaturated zones

16. Waste Interaction with Hydrologic Cycle

18. Changes Occurring in a Waste Dump
Biological Changes
During the aerobic decomposition, carbondioxide is the principal gas produced.
Once the available oxygen has been consumed, the decomposition becomes anaerobic and the organic matter is converted to
Carbondioxide
Methane
Trace amounts of ammonia
Hydrogen sulfide
Many other chemical reactions are also biologically initiated therefore it is difficult to define the condition that will exist in any waste dump at any stated time.

19. Chemical Changes
The chemical reactions that occurs in a waste dump are
Dissolution
Suspension of waste materials
Biological conversion products in the liquid percolating through the waste
Evaporation and vaporization of chemical compounds
Sorption of volatile and semi volatile organic compounds into the waste material
Decomposition of organic compounds
Oxidation-reduction reactions affecting metals and the solubility of metal salts.
The dissolution of biological conversion into the leachate is of special importance because these materials can be transported out of the waste dump with the leachate.

20. Physical Changes The important physical changes in waste dumps are
Lateral movement of gases in the waste
Emission of gases to the surrounding environment
Movement of leachate within the waste and into underlying soils
Settlement caused by consolidation and decomposition of the waste.

21. Impact on Environment

22. SUBSURFACE DISPOSAL TECHNIQUES
Deep wells
Injection wells
Mine Shafts
Entrenchment
Landfills

23. 1.Deep-well Disposal
In rock (not soil), isolated from freshwater aquifers; waste is injected into a permeable rock layer hundreds to thousands of meters below the surface.
Deep-well injection of oil-field brine has been important to control water pollution in oil fields for many years.

24. USES
Petroleum industries- recovery of oil and for brine waste

25. 2.INJECTION WELL DISPOSAL
Deep-well injection system -- disposal in sandstone or fractured limestone capped by impermeable rock and isolated from fresh water. Monitoring wells are a safety precaution.
Disposal of hazardous waste
Hazardous liquid waste placed in well confined geological formations that are deep below earths surface

27. Deep well injection directly introduces liquids into a deep aquifer in the subsurface environment via pressurized wells.
CLASS I WELLS - used for disposal of hazardous and non-hazardous industrial or municipal wastes.
CLASS II WELLS - used for injection of oil field brines and other hydrocarbon wastes.
CLASS III WELLS - used for solution mining processes.
CLASS IV WELLS - those which historically disposed of radioactive wastes (this is no longer done).
CLASS V WELLS - used for any activity not mentioned above, such as geothermal steam mining operations.

29. Parameters- Construction of deep wells
Low pressure
Large area extent
High porosity and permeability
Nature of aquifer
Seperation from freshwater horizon
Geological strata
Type of waste

30. 3. MINE SHAFTS
Solidified waste packed in non breakable containers ( concrete cylinders, drums)
These are transported down the shafts placed in chambers
Chambers sealed
Indefinite life- unless corroded from inside
Sites chosen – Salt, potash and gypsum deposits

31. 4.Entrenchment Modified landfill method
Refuse placed in trenches & buried
Trenches- 3m deep, 1mwide, 10m long
Monitored for 24 months
If made in clayey soil- no problems of GW contamination & odour problem
Sites can be used for vegetable production

33. Concept of Landfilling

34. The components of the engineered landfill are
Liner system
Leachate collection and treatment facility
Gas collection and treatment facility
Final cover system
Surface water drainage system
An environmental monitoring system
A closure and post closure plan

35. PHASES OF LANDFILL PROJECT
1. Siting 2. Designing 3. Construction 4. Operation 5. Closure of landfill

36. 1. SITING A LANDFILL Topography
Alluvial/ sedimentary formations suitable
Base above saturation zone
Prevent standing water
Prevent erosion and runoff
Excessive sloping (1% but less than 10%)

37. Climate
Low rainfall
High surface evaporation rates
Groundwater
Location and quality
Flood plains
Outside floodplains
Surface water
Prevent runoff

38. Air quality
Monitored
Controlled
Availability of transport system
Convenient transport facilities
Hydrogeology
Low permeability ( not exceed 107 cm/s)
Texture of soil
Fine grained soil – low Leachate penetration

39. 2. DESIGNING-Landfill Section
Depending on:
Topography of the area
Depth of ground water table
Availability of suitable daily cover material.
1.Above ground landfills
Above ground landfills are used in those areas where GWT is high.
-Used when terrain is unsuitable for excavations

40. 2.Below ground landfill
suitable for areas where adequate cover material is available and GWT is not near the surface.
Solid waste dumped in trenches excavated in soil
Trenches-
Length :100 to 300m
Depth: 3 m
Width :5 to 15 m
Side slope : 2:1

41. 3.Above and below ground landfill--------
4.Slope landfill 
5.Valley landfills 

42. Implications of Disposal Above, On and Below Ground Surface
Above Ground Landfills
Advantage
Drainage of leachate is by gravity.
Thickness of unsaturated zone below
the landfill is large.
Landfill is conspicuous and thus cannot
be ignored.
Poor surface drainage due to
settlement of final landfill surface can
be avoided.
Inspection of the entire facility i.e. final
cover, leachate collection system and
gas collection system is easier.
Disadvantage
They alter the land use
pattern of the area.
They have more surface area
exposed to elements of nature
such as wind, rain and require
significant erosion control
measures.

43. On and Just Below Ground Surafce
Disadvantage
Leachate collection through
regular pumping.
Require good surface water
drainage measures if
located in low lying areas
and are closer to ground
water table than above
ground landfills.
Advantage
More waste can be stored per unit land area in comparison to above ground landfills.
Efficient use can be made of the excavated material but using it as landfill cover.
Productive use of the flat landfill surface can be made on completion of landfill.
Long term slope stability and erosion control requirements are not very critical in such landfills.

44. Landfills Deep Beneath the Earth’s Surafce
Wastes can also be dumped in underground openings, tunnels or caverns, however the cost of construction in such cases is extremely high.
If the disposal is in soil where water table is high, the waste would always be surrounded by ground water and, irrespective of the multiple barriers used for waste isolation, the potential of ground water contamination would always be high.

45. If waste is disposed in strong competent rock: the very low permeability of the rock mass coupled with multiple barriers layers ensures long term containment of the waste.
Such disposal techniques are adopted for extremely hazardous waste
Waste disposal deep beneath the ground surface has the least impact on the land use pattern.

46. Landfill Layout
A landfill site will comprise of the area in which the waste will be filled as well as additional area for support facilities. With in the area to be filled, work may proceed in phases with only a part of the area under active operation.

48. Engineered Landfills

49. The main design phase includes
Design of liner, leachate collection and Treatment
Gas Collection and Treatment
Cover System
Landfill Stability
Surface Water Drainage
Environmental Monitoring

50. a. Phase:-
sub area of the landfill.
consists of cells, lifts, daily cover, intermediate cover, liner and leachate collection facility, gas control facility and final cover over the sub-area.
designed for a period of 12 to 18 months.
b. Cell:-
volume of material placed in a landfill during one operating period usually one day.

52. c. Daily cover:-
-It consists of 15 to 30 cm of native soil that is applied to the working faces.
Purpose of cover :
To control the blowing of waste materials
To prevent rats, flies and other disease vectors from entering or exiting the landfill
To control the entry of water into the landfill during operation

53. d. Lift:-
-It is a complete layer of cells over the active area of the landfill.
-Typically each landfill phase is comprised of a series of lifts.
-Intermediate covers are placed at the end of each phase; these are thicker than daily covers and remain exposed till the next phase is placed over it.
e. Bench:-
-A bench is a terrace which is used when the height of the landfill exceeds 15 to 20 m.
f. Final cover layer
The final lift includes the cover layer.
applied to area after all landfill operations

56. g. Leachate Collection Systems
To prevent migration of leachate generated inside a landfill from reaching the soil and ground water beneath the landfill.
Function of leachate collection facility:
Remove leachate contained with in the landfill by the liner system for treatment and disposal.
Control and minimize leachate heads with in the landfill.
Avoid damage to the liner system.
Landfill liner comprise of
Compacted clays
Geomembranes
Geosynthetic clay liner
Combinations

57. h. Gas Collection Systems
The uncontrolled release of landfill gas, methane contributes to the green house effect.
Landfill gas can migrate laterally and potentially cause explosions.
Landfills are therefore provided with gas collection and processing facilities.
The rate of gas production varies depending on the operating procedure.
The decision to use horizontal or vertical gas recovery wells depends on the design and capacity of the landfill.

58. Reasons why landfill operated in phases
Progressive use of the landfill area such that at any given instant of time a part of the site may have
-a final cover,
-a part being actively filled,
-a part being prepared to receive waste and
-a part in an undisturbed state.
Minimizes the area required for landfill operations- concentrates waste disposal activities within prepared areas.
Reduces leachate generation by keeping areas receiving waste to a minimum.
Enables progressive installation of leachate and gas control.
Allows clean surface water runoff to be collected separately.

59. 3. Construction & Operation Design Process
Site Development
Construction Schedule
Material and Equipment Requirement
Enviornmental Control During Operation
Closure and Post Closure Programmes

60. 1. Material requirement
Material requirement plan for the construction of various phases of the proposed landfill -prepared
Materials may be required for
Granular material for ground water drainage, leachate drainage blanket, gas venting and collection
Clay, sand, synthetic membrane for the liner system and final cover system
Suitable fill for internal and external bunds
Base course and sub base course materials for haul roads
Suitable material during site operations for daily cover
Suitable soils or granular or screened material for pipe work zone, drainage and protection layers above the barrier layer
Sub soil and top soil for restoration layers

61. 2.Equipment Requirement
The type, size and number of equipment required will depend on the size of the landfill and maneuverability in restricted spaces.
Equipments are required at the landfill site
For excavating, spreading and leveling operations crawler tractors/dozers are required
Compactors/rollers for compacting
Wheeled loader-back hoes for excavating, trenching, loading and short hauling

62. 3. Environmental control during operation
Carried out to minimize the impact of the landfilling operation on the nearby residents. This can be done by:
Providing screens in the active areas
Presence of birds at the landfill site (nuisance if the landfill is being constructed near the airport)
over come by:
Use of noise makers
Use of over head wires
Use of recording of the sounds made by birds

63. Problems of wind-blown paper, plastics etc overcome by
Portable screens near the operating faces
Daily removing the accumulated materials on the screen
Dust control can be achieved by spraying water
Problems of flies, pests, mosquitoes and rodents can be controlled by :
-placing daily cover
-by eliminating stagnant water.

64. 4.Closure and post closure plan
A closure and post closure plan shall be made to ensure that a landfill will be maintained for years in the future
A closure plan includes
Landfill cover and landscaping of the completed site.
Long term plans for the control of runoff, erosion, gas and leachate collection & treatment.

65. Post closure plan includes
Routine inspection of completed landfill.
Maintenance of surface water diversion facilities, landfill surface grades, the condition of liners.
Maintenance of landfill gas and leachate collection equipment.
Long term environmental monitoring plan so that no contaminants is released from the landfill site.