Hazardous Waste Management Hierarchy
SECURED LANDFILL
A controlled site for disposal of wastes on
land, run in accordance with safety and
environmental requirements laid down by a
regulatory authority
A FACILITY WHERE

WASTES ARE PLACED PERMANENTLY IN
SECURED MANNER

WASTE IS ENCAPSULATED FROM THE
ENVIRONMENT BY IMPERMEABLE BARRIERS/
LINERS

LEACHATE IS COLLECTED, REMOVED &
TREATED THROUGHOUT ITS LIFE.
WHY LANDFILL ?
 All hazardous waste treatment options
result in residues and One of the safer
methods for disposal of them
 Best techno-economic option for some
wastes.
SECURED LANDFILL FACILITY
•
Last Option
•
Primarily Containment of contaminants
TYPES OF LANDFILL
ATTENUATE & DISPERSE:
Sites where leachate and waste is allowed to
escape into the environment at a controlled rate.
Pollution is reduced by degradation and attenuation
within the landfills and by dilution of the leachate in
the aquifer
Containment : Sites are aimed at isolating wastes
and leachate from the surrounding environment for a
considerable time.
Archival : Sites are specifically engineered to
contain wastes indefinitely, but also to permit later
identification and retrieval.
METHODS OF LANDFILL
Co-disposal : Disposal with M.S.W or similar wastes
to take advantage of attenuation
processes occuring in such wastes;
Critical assessment for compatibility
Mono-disposal: Disposal of wastes having same
general physical and chemical form
Multi-disposal: Disposal of chemically different
wastes in the same site
MULTI-BARRIER SYSTEM FOR SLF DESIGN
Barrier No: 1
Degradation or fixation of pollutants in the waste prior to
disposal
Barrier No: 2
Suited location of the landfill site with regard to the
geological/ hydro-geological situation of the area
Barrier No: 3
Leachate collection and treatment system
Barrier No: 4 :
Bottom Liner System
Interface between waste body &
subsoil hinders leachate percolation.
Barrier No: 5
Cover Liner System
Avoids penetration of surface and
rain water into waste body avoiding
formation of leachate
Barrier No: 6
Proper operation and maintenance of
SLF
Barrier No: 7
Post Closure measures & Repairability
of barriers
BASIC COMPONENTS OF LANDFILL
• Impermeable Liner System on the base and side
• Top cover
• Leachate collection, removal and treatment scheme
• Surface Water Control Systems
•
Other site infrastructure
Landfill
Why the Liner is required ?
Isolate
the waste body from the environment
Contain

the toxic leachate within landfill
Prevent contamination of Land and Groundwater
Avoid
remediation in future
Which liner systems are
available?

Mineralic
 Geo-membrane
 Composite (Mineralic + Geo-membrane)
 Geo-synthetic Clay/ Bentonite Mats
 Bituminous Membrane
 Asphalt Concrete Liner
BOTTOM LINER
•
Prevent migration of wastes or ‘by-products’ out of the
landfill into subsoil, ground or surface water
•
Should have chemical properties, sufficient strength and
thickness to prevent failure due to :
-
Pressure gradients
-
Physical contact with the waste or leachate
-
Climatic conditions
-
Stress of installation and
-
Stress of daily operation
TYPICAL BOTTOM LINER COMBINATIONS

CLAY LINER ONLY

ASPHALTIC CONCRETE LINER

COMPOSITE LINERS

ONE CLAY LINER & ONE FLEXIBLE MEMBRANE LINER

ONE CLAY LINER & TWO FLEXIBLE MEMBRANE LINERS
Single Composite liner system (As per CPCB)
Waste Body
Leachate collection layer
thickness> = 30 cm., k>=10-2 cm/s
HDPE Geomembrane
thickness> = 1.5 mm or more.
Compacted clay/ compacted amended soil
thickness >= 45 cm, k<=10-7 cm/s
Sub soil
Total Thickness
# 45 - 60 cm
DOUBLE COMPOSITE LINER (AS PER CPCB
GUIDELINE)
ASPHALTIC CONCRETE LINER
WASTE BODY
3 SEAL LAYERS
2 BASE LAYERS
FOUNDATION LAYER
USEPA SPECIFICATION FOR BOTTOM
LINERS
Three type of liners are specified by USEPA
• Flexible Membrane Liners (FMLs)
• Compacted Clay Liners
• Composite Clay Liners (FML + Compacted
Low permeability soil liners)
MATERIALS FOR FMLs
 Chlorosulfonated
Polyethylene
 Linear LDPE / Very LDPE
 Polypropylene
 Ethylene Inter polymer alloy
 Neoprene
 Poly Vinyl Chloride
 Thermoplastic elastomers
 HDPE
Key factors considered for
selection of FML
• Chemical compatability with waste leachate
• Ageing and durability
• Stress and strain characteristics
• Ease of installation
• Water permeation
CPCB Specification for Geomembrane Liner
Special Physical and Mechanical Requirements:
1. Performance under tensile load
2. Tear Resistance
3. Puncture Resistance
Requirements with respect to Combined Physical and
Chemical Attack
1. Stress Crack Resistance
CPCB Specification for Geomembrane Liner
Specifications of HDPE Geomembrane (thickness 1.5 mm or
more)
 Tensile Strength at yield
= > 18 kN/m.
 Tensile Strength at break
= > 30 kN/m.
 Tear Resistance
= > 150 N
 Puncture Resistance
= > 250 N
CLAY LINER –USEPA SPECIFICATION
Thickness of compacted clay bottom liner = 3 feet
Permeability of soil liners < 1 x 10-7 cm/sec
To achieve this, following characteristics of soil should be met.
•
Soil should have at-least 20% fines i.e. fine silt and clay sized
particles
•
Plasticity Index (PI) > 1% (soils with PI higher than 30 to 40%
are sticky and difficult to work within the field)
•
Coarse fragments should be screened to no more than about
10% gravel size particle.
•
No soil particles or chunks of rock larger than 1 – 2 inches in
diameter.
BLENDED SOILS –USEPA SPECIFICATION
• On-site soils can be blended with imported clay
minerals.
(e.g on-site sandy soils + imported sodium bentonite)
• Calcium bentonite, lime, cement, clay soil from nearby
or other areas ,etc are also used.
• Clay soil is likely to form chunks and difficult and hence
easier to blend on-site sandy soils with dry bentonite
powder.
COVER LINER (AS PERCPCB GUIDELINE)
Slope 3%
Cover Liner
2m
Soil Bund
2m
2:1
HDPE Liner
A
A
0.5m
375 m
0.7 m
Gravels
Storm Water Drain
Channel
Section
USEPA GUIDELINES FOR TOP LINER
VEGETATIVE COVER – MIN. 60 CM THK
(UPPER SLOPE : 2 TO 5 %
SOIL DRAINAGE LAYER – MIN. 30 CM THK
FLEXIBLE MEMBRANE LINER (MIN. 20 MILS )
COMPACTED SOIL – MIN. 60 CM THK
WASTE BODY
TOP LINER – NPC DESIGN
VEGETATION
2 X 25 CM THK MODERATELY
COMPACTED SOIL
2 X 25 CM THK WELL COMPACTED SOIL
3 MM THK POLYESTER BASED
MODIFIED BITUMINOUS FELT
25 CM THK COMPACTED SOIL
WASTE BODY
SIDE LINER – NPC DESIGN
WASTE BODY
MASTIC ASPHALT LAYER 2CM THK
3 MM THK POLYESTER BASED
MODIFIED BITUMINOUS FELT
75 MM THK P.C.C 1:3:6
COMPACTED SUBBASE
LEACHATE COLLECTION & REMOVAL
•Drainage Layer
•Granular (Sand or gravel, no fine, 2-5 cm dia particle,
thk, min K=1 cm/s)
min.30 cm
•Synthetic (nets, mats, geo-textiles)
•Pipes and Appurtenances
•Cushions
LEACHATE STORAGE & TRANSFER
Epoxy coated RCC Sump with level control submersible pump
LEACHATE TREATMENT
SURFACE WATER CONTROL SYSTEMS
RUN-OFF
Collect and control run-off from active and inactive portions of
the landfill from 24 hour – 25 year storm
Collect and contain leachate contaminated storm water that
accumulates in active fill area
Protect integrity and effectiveness of landfill cover system
RUN-ON
Intercept and divert run-on away from active and closed land fill
cells from peak discharge of 25 year storm
 Minimise site erosion
GROUND WATER MONITORING
Designed to detect contaminant leakage shortly after its
occurrence and before significant contamination of ground water
Hydraulically up-gradient and down-gradient wells
Placed around perimeter of fill area within several hundred feet
of SLF
No. of wells- Site specific, depends on Size of SLF,
Hydro-geology
Minimum Requirements
1 well in up-gradient (Background)
3 wells in down-gradient
IDENTIFICATION OF WASTES THAT CAN BE
LANDFILLED
1.Wastes that will definitely need to be landfilled
as no other options are practicable
e.g. Asbestos
2. Wastes that could be safely landfilled without
prior treatment
e.g. Bio-degradable wastes – technically possible;
Better options often exist.
3.Wastes which could be landfilled after
pre-treatment
e.g., Liquid wastes; heavy metal salts.Pretreatment options can include detoxification,
precipitation, solidification as appropriate
4. Wastes that should not be landfilled
e.g., Explosives, Compressed toxic gases, Liquid
PCBs for technical reasons
CRITERIA FOR DISPOSAL OF H.W IN SLF
•
To be dewatered up to the level of 60 – 70% solids
•
Following are not be allowed to dispose of directly in SLF if
waste
-
Is a fluid, slurry or paste
-
Is delivered under pressure or under vacuum
-
Has an obnoxious odour
-
Reacts with moisture to generate high heat or gases
-
Is highly inflammable (flash point < 40oC)
-
Contains very strong oxidising agents
-
Contains volatile substances of significant toxicity
CRITERIA FOR DISPOSAL OF H.W IN SLF
- Contains > 10 mg/Kg Cyanide in the original sample
- Contains > 10 mg/kg Chromate in the original sample
- Contains > 0.5% (Wt.) Mercury
- Falls below a pH value of 2, if eluated 1/10
- Contains > 10 mg/1 of water soluble Arsenic in a 1/10 eluate
- Contains > 10 mg/1 of water soluble Mercury in a 1/10 eluate
- Contains > 3% solvents free from Halogen
- Contains more than 0.5% Halogenated solvents
- Contains > 0.1% poly-halogenated substances of Significant toxicity
(PCBs)
Criteria for Hazardous Waste
Landfilling in Germany due to
“Technical Instructions for HWM”
1991
ELUATE QUALITY
PARAMETER
VALUE
pH
4 – 13
Conductivity
<100,000
Total Organic Carbon
<200 mg/1
Phenols
<100 mg/1
Arsenic
<1 mg/1
Lead
<2 mg/1
Cadmium
<0.5 mg/1
Chromium VI
<0.5 mg/1
Copper
<10 mg/1
Nickel
<2 mg/1
Mercury
<0.1 mg/1
Zinc
<10 mg/1
Fluoride
<50 mg/1
Ammonia
<1,000 mg/1
S/cm
ELUATE QUALITY
PARAMETER
VALUE
Chloride
<10,000 mg/1
Cyanide
<1 mg/1
Sulphate
<5,000 mg/1
Nitrite
<30 mg/1
AOX
<3 mg/1
Water sol. Content
<10%
STRENGTH
Transversal Strength (Vane
Testing)
>25 kN/m2
Unconfined Compression Test
>50 kN/ m2
Axial Deformation
>20%
DEGREE OF MINERALISATION OR CONTENT OF ORGANIC
MATERIALS
Annealing loss of the dry residue
at 550oC
<10 W.%
CPCB CRITERIA FOR NON- ACCEPTANCE OF
WASTE IN SLF
 Bulk or non-containerized liquid
hazardous
waste
Slurry type hazardous waste containing free liquid
or waste sludge
Incinerable / compostable waste or any other type
of waste from which energy recovery is feasible
In-compatible wastes not to be placed in same
landfills
CPCB CRITERIA FOR NON-ACCEPTANCE OF
WASTE IN SLF
Wastes in-compatible with liner material without
containerisation
Extreme hazardous waste (e.g radioactive waste)
 Non-hazardous
waste
deposited in HW Landfills
(e.g
MSW)
not
to
LIST OF INCOMPATIBLE WASTES
1
Oxidising mineral acids
1
2
Caustics
H
3
Aromatic hydrocarbons
H,F
Halogenated organics
H,F,
GT
4
2
3
H,
GF
Metals
6
Toxic metals
7
Sat. Aliphatic Hydrocarbons
H,F
8
Phenols and cresols
H,F
9
Strong oxidising agents
10
Strong reducing agents
11
12
S
ExPLOSIVE
F
FIRE
GF
FLAMMABLE GAS
GT
TOXIC GAS
H
HEAT GENERATION
S
SOLUBILISATION
4
GF,
H,F
5
E
H,F
5
S
OF TOXINS
6
7
8
H
H,F
H,F
H
9
GF,
H
H,F
GT
H,
GT
Water and mixtures containing
water
H
H,E
Water reactive substances
Extremely reactive: do not mix with any chemical or waste material
S
H,F
E
10
GF,
GT
11
12
CPCB SPECIFIED DESIGN
REQUIREMENTS FOR LINERS
 Stability at base of landfill (in soft soil) & in sides
 Strength to withstand construction loads/ vehicle
loads
Permeability and material properties as specified
in guidelines
Compatibility with leachate & waste
Transition filters bt. Waste & leachate collection
layer to prevent clogging of leachate collection layer
CRITERIA FOR HAZ. WASTE LANDFILLS
CONSTRUCTION & OPERATION CRITERIA
INSPECTION,
MONITORING
&
RECORD
KEEPING CRITERIA
POST-CLOSURE CRITERIA
FINANCIAL ASSURANCE CRITERIA
CONTIGENCY PLAN FOR EMERGENCIES
CRITERIA FOR HAZ. WASTE LANDFILLS
LOCATIONAL CRITERIA
SITE SELECTION
SITE INVESTIGATION CRITERIA
PLANNING & DESIGN CRITERIA
WASTE ACCEPTANCE CRITERIA
LANDFILL
CRITERIA
LINER
CRITERIA
&
COVER
CPCB SPECIFIED DESIGN REQUIREMENTS
FOR LINERS
 Protection layer / transition layer between each
component of liner system may be provided
Between Leachate collection layer & HDPE
With Silt / local earth (15 cm thk) / Geo-textile
 Adequate clay additive in amended soils
ASPECTS CONSIDERED IN THE DESIGN OF SLF

Selection of appropriate liner system for SLF

Desired design period of the SLF in years

Type of landfill desired
 Pit (cell wise development) / continuous

Depth of hard stratum from G.L.

Total lay out size & total area of the SLF
Nearest G.W.T. reported in monsoon season
 Depth of landfill below ground level

Height of stock pile above ground level

Inner side, bottom – longitudinal & transverse slopes

Provision and layout of roads, storm water drain, green
belt, office, security, lab, weigh bridge, Vehicle washing
area, leachate sumps, etc around the SLF
BROAD DESIGN BASIS FOR SECURED LANDFILL FACILITY
Quantity of sludge generated

Evolving specific sludge generation factor (I.e. ton of
sludge / ton of product)

Sludge generation for envisaged production in future
Characteristics of sludge generated
Specific gravity of dry solids in sludge
Bulk density of raw sludge

Sludge treatment requirements




Moisture content of sludge
Results of Eluation tests
Chemical composition of sludge
Moisture content, density & other characteristics of sludge
after treatment
SITE CRITERIA
•
Topography of the site area
•
Geological
/
Hydro-geological
(characteristics of the subsoil,
situation
the
site
presence of aquifers layers,
ground water table etc.)
•
of
Rainfall situation in the region of the site area
AREA REQUIREMENT FOR SLF
Height of Landfill = 5- 20 m
Infrastructure, support facilities & green belt = 15 -20 % of landfill
Landfill size classification
Small
: < 5 hectares
Medium
: 5- 20 hectares
Large
: > 20 hectares
QA/QC Plan during construction of SLF
 Permeability check of Mineralic Liner
 Material Testing as per specifications
 Compaction, Moisture content of Mineralic Liner
 Vacuum Testing for HDPE Joints
Why does well designed SLF fail ?
Improper operating practices
 Allowed too much liquid to enter into the landfill
 Cracks, punctures and physical failure of liners
 Clogging of leachate collection systems
 Consolidation may result in breaks in the liner or the
cover material
 Disposal of solvents which affects the liner
 Improper Joints