the bioreactor landfillorganic polymer-containing waste monomers alcohols organic acids fe(iii) no...
TRANSCRIPT
THE BIOREACTOR LANDFILL PARADIGM
Frederick G. Pohland, Ph.D., P.E.Professor and Weidlein Chair of Environmental
EngineeringUniversity of Pittsburgh
Pittsburgh, PA 15261, USA
2003 EPA Bioreactor Landfills WorkshopArlington, VA
OUTLINE OF PRESENTATION
• Fundamental Definitions
• From the Way We Were
• Today and Beyond
FUNDAMENTAL DEFINITIONS
• Reactor– a containment structure in which reactions are initiated and
controlled to optimize a desired outcome
• Bioreactor– a biologically-mediated reactor
• Bioreactor Landfill– a bioreactor where the containment structure is a landfill or a
portion of a landfill
FUNDAMENTAL DEFINITIONS (Cont’d.)
• Paradigm– an example, model or archetype of which all things of the same
type are representatives or copies
• Bioreactor Landfill Paradigm– a landfill archetype with leachate recirculation to accelerate
and/or enhance biodegradation and stabilization
FROM THE WAY WE WERE
• Past Landfill Practices– uncontrolled dumping/impacts
• The Emergence of a Paradigm– leachate and gas management– engineered landfill systems
• Scientific and Technical Renaissance– translation of fundamental scientific principles into rationale
design, operation and control
• Regulatory Impacts– away from command and control
H2 HAc
Fe(II)NH3H2SN2
ORGANIC POLYMER-CONTAININGWASTE
MONOMERS
ALCOHOLS
ORGANIC ACIDS
Fe(III)NO3
-
SO42-
HCO3-
CH4
H2O
Legend
: Electron donors
: Electron acceptors
: Precursor byproducts
: End products
Waste Conversion Sequences in Landfill Bioreactor Systems
Stabilization characteristics within a bioreactor landfill unit
Stabilization Time, Days
Gas
Com
posi
tion,
% b
y Vo
lum
e
0
20
40
60
80
100
CO
D, T
VA, g
/L
0
10
20
30
40
50
Incr
emen
tal G
as P
rodu
ctio
n, m
3
0.0
0.2
0.4
0.6
0.8
1.0
pH
5
6
7
8
Amm
onia
, mg/
L
0
1000
2000
3000
OR
P, m
V Ec
-150
-100
-50
0
50
100
150
pH
Ammonia
ORP
N2
COD
O2
TVA
H2
CH4
CO2
Incremental Gas Production
O2
Phase IInitial
Phase IITransition
Phase IIIAcid
Formation
Phase IVMethane Fermentation
Phase VFinal
Maturation
0 200 400 600
Sulfi
de, m
g/L
0510152025
H2S
Note: a pH 7, 1 atm, 1 kg/mol activity, 25oC
-1,120.52NO3- + 5H2 + 2H+ ↔ N2 + 6H2ONitrate ↔ Nitrogen Gas
-511.4CH3COO- + NO3- + H+ + H2O ↔ 2HCO3
- + NH4+
-599.6NO3- + 4H2 + 2H+ ↔ NH4
+ + 3H2O
Nitrate ↔ Ammonia
-59.9CH3COO- + SO42- + H+ ↔ 2HCO3
- + H2S
-151.9SO42- + 4H2 + H+ ↔ HS- + 4H2O
Sulfate ↔ Sulfide
-135.6HCO3- + 4H2 +H+ ↔ CH4 + 3H2OHCO3
- ↔ Methane
-104.62HCO3- + 4H2 + H+ ↔ CH3COO- + 4H2OHCO3
- ↔ Acetate
Reductions (Electron Accepting Reactions)a
-31.0CH3COO- + H2O ↔ HCO3- + CH4Acetate ↔ Methane
-4.2CH3CHOHCOO- + 2H2O ↔ CH3COO- + HCO3- + H+ + 2H2Lactate ↔ Acetate
+9.6CH3CH2OH + H2O ↔ CH3COO- +H+ + 2H2Ethanol ↔ Acetate
+48.1CH3CH2CH2COO- + 2H2O ↔ 2CH3COO- + H+ + 2H2Butyrate ↔ Acetate
+76.1CH3CH2COO- + 3H2O ↔ CH3COO- + HCO3- + H+ + 3H2Propionate ↔ Acetate
+48.4CH3(CH2)4COO- + 2H2O ↔ CH3(CH2)2COO- + CH3COO- + H+ + 2H2Caproate ↔ Butyrate + Acetate
+96.7CH3(CH2)4COO- + 4H2O ↔ 3CH3COO- + 2H+ + 4H2Caproate ↔ Acetate
+48.3CH3(CH2)4COO- +2H2O ↔ 2CH3CH2COO- + H+ +2H2Caproate ↔ Propionate
∆G, kJOxidations (Electron Donating Reactions)a
Redox Half-reaction Responsible during Anaerobic Stabilization in Bioreactor Landfills
Bioreactor landfill attenuation of representative recalcitrant organic and inorganic constituents*
* References: Pohland et al. (2002).** Perchloroethene (PCE), Trichloroethene (TCE), Dibromomethane (DBM), Hexachlorobenzene (HCB), Trichlorobenzene (TCB), Dichlorobenzene (DCB), Dichlorophenol
(DCP), Nitrophenol (NP), Nitrobenzene (NB), Bis (2-ethylhexyl)phthalate (BEHP), Naphthalene (NAP), Lindane (LIN), Diedrin (DIEL); includes daughter products.
Conversion to a reduced oxidation state with complex formation and volatilization (Fe, Cr, Hg).
Mobilization and salt formation in leachate in the presence of organic (e.g., aromatic hydroxide, carboxylic acid, aromatic amine, humic and fulvic acid) and inorganic (e.g., chloride, sulfate, carbonate) ligands.
Formation of sparingly soluble hydroxides (Cr) and sulfates (Cd, Cu, Fe, Hg, Ni, Pb, Zn) after sulfate reduction, and precipitation.
Physical sorption and ion exchange within the waste matrix.Filtration and retention within stagnant pools of interstitial water.
Heavy Metals(Cd, Cu, Cr, Fe, Hg, Ni, Pb, Zn)
Low volatility and mobility in gas and leachate prior to complete or partial biodegradation.Phthalate Esters (BEHP), Polynuclear Aromatics (NAP), and Pesticides (LIN, DIEL)
Mobilization in leachate prior to dechlorination or nitro-group reduction, biodegradation and complexation.
Phenolics and Nitroaromatics(DCP, NP, NB)
Volatilization and sorptive matrix capture prior to partial reductive dechlorination.Chlorinated Benzenes(HCB, TCB, DCB)
Volatilization and mobilization in gas and leachate prior to abiotic and biotic reductivedehalogenation under methanogenic, methanotrophic, sulfate reducing and denitrifying conditions.
Organic Compounds**
Halogenated Aliphatics(PCE, TCE, DBM)
Dominant Attenuation Mechanisms during Landfill Stabilization PhasesConstituents
TODAY AND BEYOND
• Needs Assessment and Resolution– Scientific and technical inquiry/discovery/application
• Rational Management and Oversight– Checks and balances
• Stakeholder Harmonization– Perspective and participation
• Sustainability– Goals achievement
Bioreactor Landfill with Leachate and Gas Treatment Options
LANDFILL
GAS TREATMENT
PIPELINEQUALITY
ON-LINEFLARING
IN SITUVS.
EXTERNAL TREATMENTLEACHATE RECYCLE
BIOLOGICAL TREATMENT
ACTIVATED SLUDGE ANAEROBIC FILTERAERATED LAGOON ANAEROBIC CONTACTSTABILIZATION POND NITRIFICATIONTRICKLING FILTER DENITRIFICATION
EXTERNAL TREATMENT
COMBINED TREATMENT
PHYSICAL/CHEMICAL TREATMENT
PRECIPITATION/COAGULATIONCHEMICAL OXIDATION/REDUCTIONADSORPTIONION EXCHANGEREVERSE OSMOSISDISINFECTION
DISCHARGE OPTIONPOTW LAND APPLICATION
DIRECT USE
Stabilization Time, Days
Gas
Com
posi
tion,
% b
y Vo
lum
e0
20
40
60
80
100
CO
D, T
VA, g
/L
0
10
20
30
40
50
Incr
emen
tal G
as P
rodu
ctio
n, m
3
0.0
0.2
0.4
0.6
0.8
1.0
pH
5
6
7
8
Amm
onia
, mg/
L
0
1000
2000
3000
OR
P, m
V Ec
-150
-100
-50
0
50
100
150
pH
Ammonia
ORP
N2
COD
O2
TVA
H2
CH4
CO2
Incremental Gas Production
O2
Phase IInitial
Phase IITransition
Phase IIIAcid
Formation
Phase IVMethane Fermentation
Phase VFinal
Maturation
0 200 400 600
Sulfi
de, m
g/L
0510152025
H2S
Operational features of a bioreactor landfill
External LeachateRecirculation Pump Station
Final Cover
LeachateRecirculationField
DedicatedTreatment Zone
Gravel PackedTrench withPerforated Pipe
Isolation Berm
CompartmentLimit
Primary LeachateCollection System
Leak Detection System
Leachate Recharge/Gas Extraction Wells
Gas Flare
Leachate Storage
ExternalTreatmentPlant
Groundwater MonitoringWell
Internal Primary LeachatePump Station
Internal Leak DetectionMonitoring Well
External PumpStation
Stormw
ater
GasRecovery