Design, Operation and Management
of Solid Waste Landfills
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Land Disposal
(1) the relatively low cost of land and disposal
procedures;
(2) stringent controls on releases to atmosphere and
waters in the ’70s and ’80s; and
(3) the beliefs that land disposal was safe and
proper ???
Why the discharging onto and beneath the
earth’s surface has been a popular method for
hazardous waste disposal?
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Scharff, H., Afvalzorg Holding, NV (2007) “The role of sustainable landfill in future waste
management systems, ”Proceedings of ISWA/NVRD World Congress 2007, 9. 24-27 2007,
Amsterdam, Netherlands
Role of Landfill
(1) No matter how much prevention, reuse and recycling a society to
realize, there will be a role for landfill in waste management system;
(2) It is not economical to recycle or recover all waste under all
conditions; the capacity for recycling, recovery, or incineration cannot
be enough due to the fluctuation of waste generation; Some wastes
that cannot be recycled, recovered and incinerated landfill is the best
option; Any facility for recovery or incineration may be put of
operation because of maintenance, repair or accidents.
(3) The landfill sites are the “safety net” in a good waste management
system.
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Figure 1. Management of municipal waste in the EU27 in 2004 (from Eurostat (2006)
Recovery and disposal of municipal waste, http://epp.eurostat.ec.europa.eu)
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Classification
- Sanitary landfill: for MSW (Municipal Solid Waste)
= wastes from residential area + from commercial area
- Secure landfill: for hazardous waste
leachate collection, groundwater monitoring, double liners,
leakage detection, etc.
*** Engineered Facilities vs. Open Dumping Sites
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Hierarchy of the Integrated Waste
Management in Korea
Final Disposal
(Landfill)
Energy Recovery
Reuse
Prevention and Reduction
(Avoidance)
Recycling
Incineration
Zero waste
(Cossu, 2007)
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Balance of Processes
Goal direction
0 100%
Landfill (Cossu, 2007)
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Evolution of Landfilling
- open dumping
- Unsanitary landfill
fence, daily cover, control of insect pests, control of scavenging,
etc.
- 1st generation of sanitary landfill
leachate liner, leachate treatment, compaction, LFG collection
and reuse, etc.
- 2nd generation of sanitary landfill
Multibarrier concept for leachate and gas, pretreatment, after
care, environmental monitoring, etc.
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Final cover w/ vegetable zone
Rainwater control ditch
Leachate pumping
LFG Collection
Leachate collection
Slope stability
Control Hazardous gases emission
Leachatetreatment
Groundwater intrusion
Rainwater infiltration
Liner
Sanitary landfill
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Disasters of Slope Failures
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Philippines
Turkey
South Africa
Development and Types of Landfills
Siting- Haul distance
- Location restrictions: e.g., air ports, flood plains, unstable areas, etc.
- Available land area: e.g., buffer zone, storage, etc.
- Site access
- Soil conditions and topography
- Climatological conditions: temperature, wind, etc.
- Surface water hydrology
- Geologic and Hydrogeologic conditions
- Local environmental conditions: buffer zone due to noise, odor,
vectors, etc.
- Potential ultimate uses
- Public negotiation
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Definition of Terms
- Cell: Volume of wastes during one operating period (e.g., one
day) + Daily cover material
- Lift: A complete layer of cells
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Standards for Liner System in Korea
(1) Compacted Soil Liner System
100 cm (150 cm for Hazardous Waste Landfills) of compacted soil
layer
hydraulic conductivity of the soil layer < 10-7 cm/sec
* permeability vs. hydraulic conductivity
(2) Composite Liner System
50 cm (100 cm for Hazardous Waste Landfills) of compacted soil layer
+ HDPE > 2.0 mm (2.5 mm for Hazardous Waste Landfills)
(3) Leachate Collection System
Leachate collection layer > 30 cm w/ Kh > 10-2 cm/sec
Leachate collection pipers with holes
Rainwater and groundwater drainage system
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Compaction Equipment
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Tired roller
Sheepfoot roller
Smooth-wheel roller
Standards for Liner Systems
Hydraulic Conductivity
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Special Equipment for Kh
- Large-scale fixed wall permeameter (right)
- Permeameters for VOC (volatile organic
compound) solution (above)
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Installation of Liner Systems
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Seaming and Inspection of HDPE Liners
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Covers
Daily & Intermediate Covers
- Scattering of wastes
- Odor
- Insect pests and animals
- Rainwater drainage
- Accessibility
- Esthetic
* Intermediate cover needs better accessibility of heavy equipment
Final Cover
- Rainwater drainage
- Gaseous contaminants
- Vegetation (erosion, esthetic)
- LFG control (fire)
- Insect pests and animals
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Standards for Daily andIntermediate Covers in Korea
- Daily cover: soil > 15 cm after everyday practice
- Intemediate cover: soil > 30cm w/ 2% slope (when working area
is exposed more than 7 days)
- Final cover: at the closing of landfill
* Synthetic daily covers:
Performance and specification have to be approved by
government
foams, sprays, geosynthetic liners, recycled wastes (e.g., sludge,
ash, scrap tires, etc.)
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Biodegradable Film Cover
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Standards for Final Cover in Korea
- Gas drainage layer : > 30 cm
- Liner : (1) Clayey soil > 45 cm, Kh < 1x10-6 cm/sec
(2) Clayey soil > 30 cm + synthetic liner(e.g., LDPE, PVC,
etc.) > 1.5 mm
- Rainwater drainage layer : Sand > 30 cm
- Vegetation zone : > 60 cm
- Disinfection of insect pests
- Surface slope > 2%
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Alternative Final Covers (1/2)
Phytocapping in dry regions (e.g., Australia)
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Alternative Final Covers (2/2)
Capillary barrier
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Facilities in Landfills (1/2)
- Fence to prevent people and animal accessibility
- Board including landfill’s information (e.g., name of the
landfill, information of wastes landfilled, manager’s
information, designer and constructor’s information,
etc.)
- Scale
- Cleaning vehicles
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Facilities in Landfills (2/2)
- Rainwater drainage ditch: to reduce leachate
generation
- Groundwater monitoring wells: both of upstream and
downstream of groundwater system surrounding the
landfill
- Leachate storage tank with flow meters
- Leachate treatment facility (If the leachate generation
is not much, it can be delivered to wastewater
treatment plants)
- LFG treatment facility (simple burning, heat recover,
electricity generation, etc.)
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Estimations of Gas Generation in Landfills (1/3)
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
(1) Stoichiometic (Eq. 11-2, p. 388)
(2) BMP tests
(3) Lysimeter tests
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Estimations of Gas Generation in Landfills (2/3)
(2) BMP tests
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Estimations of Gas Generation in Landfills (3/3)
(3) Lysimeter tests
Landfill Leachate and Gases – 5 phases
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Landfill Gas (LFG) as a Fuel
- LFG primarily consists of CH4 and CO2 and is an energy alternative
- Pretreatment is necessary because it contains H2S, NH3, Siloxane,
etc.
- Siloxanes?
- Siloxanes are compounds that consist of Silicon, Oxygen, and
Methane (e.g., C8H24O4Si4, C10H30O5Si5, C12H36O6Si6, C6H18OSi2,
C8H24O2Si3, C10H30O3Si4, C12H36O4Si5)
- During combustion Siloxanes transform to SiO2 and cause damage,
efficiency drop, and failure of boilers and engines
- Soloxanes can be removed by adsorption
- Gas Fuels: LNG (Liquefied Natural Gas), LPG (Liquefied Petroleum
Gas) , CNG (Compressed Natural Gas), etc.
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
LandfillsEnteric fermentationsNatural gas systemsCoal miningManure managementRice cultivationStationary sourcesPetroleum systemsMobile sources
66.7
10 20 30 40 50 60 70 80
MMTCE
CH4 Discharge from Landfills
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Gas GWP Lifetime(yr)
CO2 1 variable
CH4 21 12
N2O 310 120
PCFs 140 6,300
HCFs 6,500 9,200
SF6 23,900 3,200
- CH4 emits to atmosphere from
natural wet lands, rice paddy fields,
ruminants, gas and oil wells, landfills,
etc.
- Among the emission sources,
landfills are most dominant
anthropogenic source
LFG Extraction Wells
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Radius of influence
Passive and Active Controls of LFG Migration
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
A Case Study for Active Control of LFG
190300 190400 190500 190600 190700 190800 190900 191000
451000
451100
451200
451300
451400
451500
451600
PB1
PB2
PB3
PB4
PB5
PB6
PB7
PB8
PB9PB10
WB1
WB2
WB3WB4
WB5WB6
WB7
WB8
WB9
WB10
WB11
WB12
WB13WB14
U
P
데크진
입
V2
V6
V7
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Leachate Collection Systems (1/2)
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Leachate Collection Systems (2/2)
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Leachate Treatment
- Leachate storage tank: estimation of leachate generation rate
e.g,, HELP (Hydrologic Evaluation of Landfill Performance)
- Discharge standards
e.g., BOD 30, 50, 70 mg/l, CODcr 400, 600, 800 mg/l depending
on the discharge area
- Items: BOD, COD, SS, pH, oils, phenol, cyanide, Cr, Fe, Zn, Cu,
Cd, Hg, organic P, As, Pb, Mn, F, PCB, E coli, color, NH3-N,
inorganic N, total P, TCE, PCE, etc.
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Estimation of Leachate Generation Rate (1/2)
LA = P + S – E – WA
where LA = Leachate generation rate [L3/T]
P = Precipitation [L3/T]
S = Moisture from wastes due to consolidation,
degradation, etc.) [L3/T]
E = Evaporation [L3/T]
WA = Absorption of moisture by wastes (i.e., field
capacity) [L3/T]
(1) During landfilling
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Estimation of Leachate Generation Rate (2/2)
(2) After installation of final covers
- HELP (Hydrologic Evaluation of Landfill Performance)
(1) for landfills in plains, not good for valley areas
(2) does not consider reactions in landfills, e.g., compression,
biodegradation, etc. → may underestimate the leachate
generation rate
- Japan’s empirical equation
Q = (C/1000) x I x A
where C = Percolation coefficient
I = Intensity of precipitation
A = Landfill area
- Water balance method Example 11-12
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Limitations of HELP Model
Lombardi, et al. “Water-
balance model for
predicting the leachate
production in landfills,”
proceedings of the ISWA
World Solid Waste
Congress 2012, Florence,
Italy, 2012. 9. 17-19
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Leachate vs. Precipitation (1/3)
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Fig. 3. Comparison of precipitation and generation of leachate in a closed landfill
(Young Su Lee and Jae Young Kim (2013)
Leachate vs. Precipitation (3/3)
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
1. It was known that in a closed landfill leachate is generated mainly
by the percolation of precipitation and leachate generation is
dependent on the precipitation. However, it was found that
leachate was generated regardless of precipitation.
2. It was possible to make an fairly accurate prediction of leachate
generation only using precipitation data collected in a closed
landfill. It is suggested that the amount of leachate generation is
4-8% of monthly precipitation and about 25,000 m3/month of base
generation regardless of precipitation.
3. However, the predicted values of leachate generation for the high
precipitation seasons were not close to those observed.
Leachate vs. Precipitation (2/3)
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Fig. 4. Comparison of precipitation and prediction of leachate generation in a
closed landfill (Young Su Lee and Jae Young Kim, 2013)
Monitoring Wells for Groundwater
(1) Installation of monitoring wells
Monitoring should start before landfilling (e.g., at least 2 months
before in Korea)
Screen of groundwater monitoring well is located in the aquifer
that be directly affected by leachate leakage
(2) Frequency of monitoring
Before: > 1 / month
After: > 1 / 4 months
(3) Monitoring items
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Indicator Compounds
(1) Less loss during travel in groundwater system
(2) High original concentration in leachate
(3) High mobility in groundwater
(4) Low detection limit and easy to measure at field
(Discussion) Which compounds have these properties?
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
General Standards for Landfills (1)
- Fences :
- Sign board:
- Weighing :
- Wheel and truck washing :
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
General Standards of Landfills (2)
- Groundwater monitoring wells:
- Rainwater drainage :
- Leachate storage tank :
- Leachate treatment facility :
- LFG disposal equipments:
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Bad Cases in Korea
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Emerging Technologies in Landfills
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Classification of Landfilling Strategies (1)
Dry Moisture Wet
Air
Forced
aeration
Passive
aeration
Anaerobic
Dry
tomb
Uncontrolled
landfill
semi-aerobic
Bio
reacto
r la
ndfill
Passive change
Active control
Field capacity
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Semi-aerobic Landfill
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
- to reduce leachate strength
- to enhance stabilization reactions
- to solve hazardous contaminant problems in leachate (e.g.,
Dioxins in ash)
Washing as a Mechanical Pretreatment
Figure 4. WOW system in Japan
Leachatetreatment
(simplified treatment)Biotope
Landfill site
Treatment water
Washing tankWater treatment
Washing water
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Background
• Since the energy recovery from Incineration plants are in the range of 10%.
The world top is 30%. High temperature causes the corrosion problem due to
Cl and increase the maintenance cost dramatically. Due to the low energy
efficiency, i.e., 10-30%, incineration plants is less attractive now.
• Gasification is limited for application. Char produced from gasification has
market value only from specific species of waste such as tire. Char from
mixed waste gasification is useless.
• Due to the EU landfill directive, least organic materials are introduced into
landfills and consequently less biogas will be generated. Active gas extraction
system is not needed any more. Just passive system such as lateral pipes
and biofilter will become popular.
• Bioreactor landfill is antiquated. The service time of landfill confinement
system is not verified and even after the system fail the reaction may keep
going. It means the landfill is not a reactor anymore.
• Waste management is a combined problem solving plan. There cannot be one
solution.
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Sustainable Landfill
Sustainable landfill = Acceptable risk
Acceptable risk based on concentration or flux
Multi barriers for sustainable landfill
1. Quality of the waste: pretreatment
2. Quality of the site: geological condition
3. Landfill design and operation
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Closed landfill – Steel cover
Incinerated
residue
Shredded
dust
Home electrical
goods
Buttery
Sprinkling
water
Storage pond
Treated water
Water treatment
plant
Disposal facility using a steel plate
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Closed landfills (1/3)
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
서울대학교 공과대학 건설환경공학부폐기물실험실 (http://waste.snu.ac.kr/)
Closed landfills (2/3)
Closed landfills (3/3)
Tent type closed landfill
Detachable roof
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Offshore Disposal Sites
Figure 1. Pulau
Semakau (Singapore)
Figure 2. Amagasaki (Japan)
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Circulated Landfill
Kinu Clean Park (Japan)
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Figure 5. Equipments in a high rate MSW composting facility
- to reduce LFG generation
- to reduce settling
- aerobic composting : Windrow type or Reactor type
- Anaerobic digestion : to recover energy and nutrients
Composting as a Biological Pretreatment
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Classification of Landfilling Strategies (2)
None Separation Separated
Pre
treatm
ent
Thermal
Mechanical
Biological
None
Mixed
waste
MBP
pretreatment
RDF
incineration
Landfill of
incombustibles
Incineration
of combustibles
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
- To recovery recyclable materials
and energy
- To produce recyclable materials
(e.g., compost)
- To reduce greenhouse gas
emission, i.e., CH4
Residual Waste
Size reduction
Screening
Anaerobicdigestion
Landfilling
Energy recovery
incineration
Aerobiccuring
End-productquality
Biologicaldrying
Figure 3. A Flow Diagram of MBP Process
Mechanical Biological Pretreatment (MBP)
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
서울대학교 공과대학 건설환경공학부폐기물실험실 (http://waste.snu.ac.kr/)
Figure 1. Main MBP options currently on the market (from Martel, J.-L., et al.
“Suez Environment’s Experience of MBT Technology,” Proceedings of
ISWA/NVRD World Congress 2007, 9. 24-27 2007, Amsterdam,
Netherlands)
Aftercare
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Elapsed time
Envir
onm
enta
l Im
pac
tEnvironmental Impact
Open dumping
Dry tomb landfill
(Cossu, 2007)
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Elapsed timeOperation Aftercare
Waste Management Contaminated Soil
(Fee) (Social Cost)
(e.g., 20 yrs)
Envir
onm
enta
l Im
pac
tHow long is the aftercare period?
(Cossu, 2007)
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Sustainable landfill = low aftercare
+ low risk for short and long terms
Elapsed timeTime of Sustainability
(e.g., 20 yrs)
Envir
onm
enta
l Im
pac
t
Acceptable Impact
Alternatives
Pretreatment (e.g., MBP)
Bioreactor
Remediation (e.g., Aeration)
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Standards for Aftercare
- Period: less than 20 years after closing
- Personnels
- Rainwater drainage, leachate management and treatment,
groundwater monitoring management are the same level as they
were
- Groundwater quality monitoring: 1 / month for the first 3 years
- Slope and structure stability, disinfection
- Monitoring of surface water and soil in the surrounding area
- Environmental impact report: every 5 years by certified institutes
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Bad Cases of Closed Landfills in Korea (1/2)
Used car market Warehouse
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
- No trespassing control
- No LFG control (LFG emission)
- Failure of rainwater drainage
- Failure of vegetation (erosion)
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Bad Cases of Closed Landfills in Korea (2/2)
Stabilization Standards
items Standards
Leachate - within discharge limits for 2 years
and and BOD/CODcr < 0.1
GW - no evidence of contamination by landfill leachate
LFG - LFG generation is not growing for recent 2 years
- CH4 of LFG < 5%
Solid - Combustibles < 5% or C/N < 10
Wastes - passed the leaching test
- No significant temperature difference
etc. - No significant impact (odor, stability of structure and
slope, surface water and soil quality, etc.)
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Sampling for Evaluation and Stability
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
- Excavation and landfilling residuals in a new sanitary
landfill
- Landfill mining and treatments such as land farming,
thermal treatment, washing/flushing, etc.
- In-situ aerobic biological stabilization
- In-situ solidification
- Impermeable barrier (e.g., slurry wall, sheet pile,
geomembrane, et al.)
- Permeable reactive barrier (PRB)
Remediation/Management alternatives
for the closed landfill
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
1 year 5 year 10 year 15 year 20 year
CO
D (
mg
/L)
0
100
200
300
400
500
1st
2nd
3rd
4th
5th
6th
7th
8th
Washing Test for Specimen Excavated Solids
from a Closed Landfill
Fig. 9. Changes of Extracted COD with washing times
- Soil washing test showed that only one time of water washing could
remove almost 70% out of water-extractable COD.
- Soil washing has a great potential as a pretreatment to reduce the
organics which produce odor, gas, settlement, strong leachate, et al.
Soil:Water = 1:10 (by wt.)
Agitated for 6 hours at 200rpm
Centrifuged for 20 min at
3,000rpm
Analyze the supernatant
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
A Washing Method for Remediation of Dumping Sites
(with permission of the Hyundai Engineering & Construction Co., Ltd.)
Excavated
materials
Vibrating
feeder
Wet
vibrating
screen
Air
turbulencing
pipe
Sedimentation tank
Centrifuge
Thickener
Clean
materials
(> 3.0mm)
Clean
materials
(> 0.065mm)Dewatering
screen
Hydrocyclone
Clean
materials
(< 0.065mm)
Sludge
Coagulants
Clean Water
Clean
materials
(< 0.065mm)
Recycled water
Discharge
(or to WWTP)
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
In-situ Aerobic Biological Stabilization
- Advantages: Simple design and operation, less odor
generation (less public complaints), etc.
- Disadvantages: questionable performance, only for
organic fraction, etc.
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
In-Situ Solidification
(with permission of the Geoworks Co., Ltd.)
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Impermeable Barriers
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Permeable Reactive Barriers (PRBs)
(with permission of
the Geoworks Co., Ltd.)
PRBs based on the chemical reactions
(e.g., Fe0, Fe2+, Pd/Fe, zeolite, ZanF, etc.)
NO3-N
Contaminated
groundwater
Clean
groundwater
NO3-
N2
Denitrifiers
SO42-
S0
Elemental
sulfur
Lime stone
55S + 20CO2 + 50NO3- + 38H2O + 4NH4
+
4C5H7O2N + 25N2 + 55SO42- + 64H+
PRBs based on the biological reaction
“Biobarriers”, “Biological PRBs” etc.
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Site of Sky Mound, USA
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Site of Sky Mound (Nancy Holt, 1985)
Fukuoka City, Japan
Refresh Citizen’s Agricultural Park
IMAZU Sports Park - Parking lot
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Nanji-Do, Korea (1/2)
- Najido site had been used
as a waste dumping site
for 20 years.
- No engineering as a
landfill facility
- Serious problems such as,
odor, fire, groundwater
contamination, land use,
etc.
- Finally, it was planned to
be remediated.
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Nanji-Do, Korea (2/2)
- Vertical cut-off wall for
leachate and gas migration
control (slurry wall and
sheet piles)
- Gas extraction and
utilization (heat recovery)
- Leachate pumping wells
and treatment facility
- Final cover and ecopark
construction
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Hickory Ridge Landfill, USA
Laboratory of Waste Management & Resource RecirculationSeoul National University, Koreahttp://waste.snu.ac.kr
Hickory Ridge Landfill (Atlanta, USA)
Considerations of building solar panels
on closed landfills
- Maintaining the integrity of the cap
and the gas management systems
- Limiting the depth of excavation
- Avoiding the use of heavy equipment
- Restrictions on laydown areas
- Maintaining erosion and surface
water run-off controls
- Robust safety measures and capping
system repair plans