Center for Environmental Research and Technology University of California, Riverside University of California, Davis Performance and Environmental Impact

Center for Environmental Research and Technology

University of California, RiversideUniversity of California, Davis

Performance and Environmental Performance and Environmental Impact Evaluations of Alternative Impact Evaluations of Alternative

Waste Conversion Technologies in Waste Conversion Technologies in CaliforniaCalifornia

Public WorkshopPublic WorkshopApril 14, 2004April 14, 2004



IntroductionsIntroductions

California Integrated Waste Management Board Fernando Berton – Project Coordinator

UC Riverside, College of Engineering, Center for Environmental Research and Technology (CE-CERT)

Joseph Norbeck – Co-Principal Investigator

Colin Hackett – Co-Principal Investigator

Tom Durbin – Research Engineer

Bill Welch – Development Engineer

UC Davis, Department of Biological and Agricultural Engineering

Bryan Jenkins - Co-Principal Investigator

Robert Williams – Development Engineer



Overview•CIWMB Background – Fernando Berton

•University of California Project Overview

– Tom Durbin

•Feedstocks – Tom Durbin, Rob Williams

•Processes and Products

– Tom Durbin, Rob Williams

•Environmental Impacts – Bill Welch

•Conclusions

– Tom Durbin, Rob Williams, Bill Welch



Materials Being LandfilledMaterials Being Landfilled•1989 legislation goal 50% diversion by 2000 (currently 47%)

•Organics (biogenic and fossil derived)

–Divert 10-13 million tons

–Landfill about 30 million tons

•Paper /cardboard largest category

–Recycle 4-5 million tons, Landfill 11 million tons

•Inorganic Components 8 million tons



CIWMB ProgramsCIWMB Programs

• Dec 1999 Colloquy – Started Dialogue

• May 2001 Conversion Technology Forum» Lack of political leadership

» Statutory constraints

» Lack of funding

» Economics and markets

» Lack of data

» Feedstock access

» Public perception & understanding

» Regulatory



CIWMB ActionsCIWMB Actions

•May 2001: Directed work in 5 areas:

–Interagency coordination

–Follow-up workshops/symposia

–Leveraging Fed/State $$

–Legislative proposal for small-scale grants and lifecycle analysis research

–Assist applicants in permit process



CIWMB Strategic PlanCIWMB Strategic Plan•Conversion technologies could be major tool towards zero waste

“…harnessing the energy potential in “waste” by using new and clean technology to convert the material

directly into green fuel or gas to produce electricity.”

•Strategic Plan Goals & Objectives

–Environmentally preferable technologies

–Promoting new technologies and processes

–Alternative means of diversion, including technologies that result in electricity and fuel



CIWMB Policy RecommendationsCIWMB Policy Recommendations

•Adopted April 2002

•Conversion Technology Definition

•Conforming definition to “transformation”

•Findings

•Level of credit

•Regulatory and Permitting



AB 2770 – Penultimate VersionAB 2770 – Penultimate Version

•Administration-sponsored

•Definition, findings, level of credit

•Conforming changes for counting diversion

•Provisions on CEQA, testing residue, etc.

•R&D program

–Lifecycle costs/benefits

–Feedstock amenability with different technologies

–Small-scale grant/R&D program



AB 2770 – Chaptered VersionAB 2770 – Chaptered Version

•Gasification Definition

•Lifecycle and market impacts - RTI

•Technical evaluation: UC contract

•Risk assessment issues: OEHHA contract

•Report to Legislature



Performance and EnvironmentalPerformance and EnvironmentalImpact Evaluations of AlternativeImpact Evaluations of AlternativeWaste Conversion TechnologiesWaste Conversion Technologies

in Californiain California

University of California, RiversideUniversity of California, RiversideCollege of EngineeringCollege of Engineering

Center for Environmental Research and TechnologyCenter for Environmental Research and Technology

University of California, DavisUniversity of California, Davis

Sponsored by:Sponsored by:

California Integrated Waste Management BoardCalifornia Integrated Waste Management Board



Technology Identification/EvaluationTechnology Identification/Evaluation

• Definitions

• Analysis of performance characteristics

• Technical limitations

• Commercial status

• Types of feedstocks and quality (moisture…)



Processes EvaluatedProcesses Evaluated

• Thermochemical ProcessesGasificationPyrolysisCatalytic CrackingPlasma Arc

• Biochemical ProcessesFermentationDigestionHydrolysis



Product EvaluationProduct Evaluation

• Types of Products (e.g., electricity, fuels or chemicals)

• Environmental impacts of products• Processing steps• Determine potential value of products that could

be produced from MSW [electricity & petroleum equivalent]



Environmental ImpactsEnvironmental Impacts

• Emissions and emissions sensitivity to feedstocks

• Residues (hazardous and non-hazardous)

• Nuisance factors (noise, dust, traffic)

• Other environmental impacts



• Initial work created a database (contract IWM-C0172 )

Report;

“Solid Waste Conversion: A review and database of current and emerging technologies”

Interactive* Data Base is available at:

http://cbc1.engr.ucdavis.edu/conv/home.asp

* Including downloading of complete db

Initial WorkInitial Work



Technical SurveyTechnical Survey• Overall technical evaluation – vendors surveyed

but no evaluation of specific technologies/vendors was performed

• Database of nearly 400 technologies/Vendors Initial UCD database, CIWMB database, Juniper

report, other sources

• About 70 responses received 18 pyrolysis, 22 gasification, 11 biological, 10 plasma

arc, 9 catalytic cracking or other 70% addressed survey questions

• Variety of systems and responses made it difficult to make apples to apples comparisons



Purpose of WorkshopPurpose of Workshop• Present and explain preliminary findings

• Discuss potential advantages/liabilities of alternative conversion technologies

• Provide a question and answer period

• Obtain feedback from stakeholders

• Discuss needs for additional data/information



Project TimingProject Timing• Public Workshop – discuss preliminary findings• Working Draft sent to Technical Advisory BoardComments expected by end of April

• Completed final draft reported by early May and provided to Board for May meetingPosted on CIWMB website by early May

• Peer-review and public comments through late May • Final report and responses to comments targeted for

completion by June for Board Review & approvalRelease of Final Report will be delayed to July

Board meeting if comments remain to be addressed



Feedstocks for Alternative Feedstocks for Alternative Conversion TechnologiesConversion Technologies



MSW & Diversion in CaliforniaMSW & Diversion in California

• California landfills approximately 37.5 million tons of waste annually (U.S. 231.9 million tons annually)

• 1990 Integrated Waste Management Act (AB 939) set goals to cut waste disposal by 25 by 1995 and 50% by 2000

• Diversion Rates have increased considerably from 10% in 1989 to 47% currently



1999 Waste Stream 1999 Waste Stream CharacterizationCharacterization

Material Type Estimated % of Waste Stream

Non-Organic 21%

Paper 30%

Plastic 9%

Lumber 5%

Other Organics 35%



Waste Distribution Waste Distribution Mass/EnergyMass/Energy

0

5

10

15

20

25

30

35

40

45

50

Paper

/Car

dboa

rdFoo

d

Leav

es a

nd G

rass

Other

Org

anics

C&D Lum

ber

All non

-Film

Plas

tic

Film P

lastic

Branc

hes a

nd st

umps

Textile

s

Fra

ctio

n o

f T

ota

l (%

)

Mass Basis Energy Basis



Energy EquivalenceEnergy Equivalence

• 2370 MW of electrical power5% of states capacity and 6% of consumption

• 60 million barrels of crude oil@ $37 barrels ----- $2.2 billion



Diversion Efforts for Misc. OrganicsDiversion Efforts for Misc. Organics

• 170 compost and Process facilities • Composting, mulch, landfill cover, biomass to

energy• Handle 6-7 million tons of organic materials• 2 million wet tons (1.6 MBDT) urban wood

waste consumed in several of the state’s 30 biomass power plants

• Approximately 15 million wet tons (~ 8 MBDT) of organics sent to landfill (C&D wood, green waste, food waste, and ‘other’)



Diversion Efforts for PaperDiversion Efforts for Paper

• Paper recycling represents 4-5 million tons (30-35%)

• Cardboard boxes – recycle rate 52%• Old newspaper – recycle rate 59%• 10 million tons of paper to landfill• 25 million tons of organic materials still sent to

landfill



Diversion Efforts for PlasticsDiversion Efforts for Plastics

• Overall recycling rates for plastics are relatively low and in the 2-4% recovery range

• PETE (soda bottle) recycling rates were over 70% in California in 1994 – up from 4% in 1988

• HDPE (milk jug) recycling rates were ~25% nationally

• Recycling rates for plastic films and other plastics which make up a predominant portion of the waste remain below 3%, however



Waste ReductionWaste Reduction• Packaging and containers32% of MSW generated, 28% of disposed MSW

• European Policies1994 EC Directive to take measures to reduce

package waste1991 German Extended Producer ResponsibilityManufacturers take back container packagingIndividual companies or central systemUS$2.25 per monthPackaging 90% recovered and 80% recycled

• Uncertain how readily such programs could be implemented in California



MSW Combustion [aka incineration]MSW Combustion [aka incineration]• 130 million tons worldwide at over 600 facilitiesRoughly 75% of waste in Japan

• 167 large facilities in US ---- 2/3rds on east coast3 in California

• Poor perception by publicIncinerators have decreased emissions

considerably



Feedstocks for Alternative Feedstocks for Alternative Conversion TechnologiesConversion Technologies

• Thermochemical processes can accept nearly all organics

• Biochemical processes generally accept only biodegradable feedstocks

Some ‘high solids’ reactors can accept more inhomogeneous waste – with the no biodegradable components exiting as digestate

• Effects of metals in pigments, etc.• PVC and chlorine containing materials can

contribute to dioxin/furan formation in thermochemical processes



Waste Distribution Waste Distribution Mass/EnergyMass/Energy

0

5

10

15

20

25

30

35

40

45

50

Paper

/Car

dboa

rdFoo

d

Leav

es a

nd G

rass

Other

Org

anics

C&D Lum

ber

All non

-Film

Plas

tic

Film P

lastic

Branc

hes a

nd st

umps

Textile

s

Fra

ctio

n o

f T

ota

l (%

)

Mass Basis Energy Basis



Biochemical Process FeedstocksBiochemical Process Feedstocks

• Biodegradable components of the landfill stream include:• Food wastes• Leaves, grass, trimmings • Paper/cardboard• Wood waste

• Biodegradation varies in rate and degree




• Biodegradation is not complete• Lignin fraction will not degrade

anaerobicallyLignin amounts:

• Wood (20-30%)• Food wastes (5-20%)• Paper (1 – 25%)

• Practical systems can not completely degrade the non-lignin components, due to time, volume, energy, and expense limitations




• Laboratory studies to determine Biomethane Potential (BMP)

• analogous to BOD assays for waste water

• Sample is digested under ideal AD conditions until no more biogas is produced (4-8 weeks)

Biogas Potentials




CH4 Generated (BTU/lb input)

Vegetable oil 16024Office paper 5609Corrugated paper 4389MSW C 2586MSW B 2466MSW D 2387Food waste 1969MSW A 1918Newspaper 1534Branches 1519Grass 1161Blend of grass, leaves, branches 1130Leaves 1123

Biomethane Potential (BMP) of some feedstocks

Energy in Biogas per wet pound of feedstock

Sources:Chynoweth, et.al., (1993)Owens and Chynoweth (1993)Eleaser, et.al., (1997)Tchobanoglous, et.al.., (1993)



LCA/ Marketing studyLCA/ Marketing study

• Examined impacts of alternative conversion technologies on recycling

• Most of results related to additional preprocessing needed for conversion technologies

• No effects on recycling of paper• Plastics recycling would increase for biochemical

processes



RecommendationsRecommendations

• Improve characterization of waste in conjunction with waste characterization studies

• Proximate, ultimate, and elemental analysisAsh, metals, toxic congeners

• Higher heating values (HHV)• Characterize protein, carbohydrates, and fats in

typical food wastes



Alternative Conversion Alternative Conversion Technologies – Processes Technologies – Processes

and Productsand Products



Conversion Processes to EvaluateConversion Processes to Evaluate

• PhysicochemicalBiodieselDistillation

•ThermochemicalHigher TemperatureHigher RateGasificationPyrolysisCatalytic CrackingPlasma Arc

•BiochemicalLower TemperatureLower RateAnaerobic DigestionEthanol FermentationHydrolysis



Post recycled MSW

Option 1Send to Landfill

Option 2Send to CT

Pre-treatment (as required)

ThermochemicalConversion

BiochemicalConversion

Products:BiogasEthanol

Chemicals

Digestate (includes lignin)Post treatment

Residue

Digestate products:Fertilizer

Soil amendmentCompost

Direct use heat or power

generation

Producergas

Synthesisgas, and liquids

and solids

Products:Fuels

ChemicalsMaterials

Residue to landfill and/or waste water

treatment.Air emissions

Cogeneration of heat and

power

All Organics Biodegradable Organics



CombustionCombustion

• Full Oxidation of fuel for production of heat at elevated temps w/o generating commercially useful intermediate gases, liquids, or solids.

• Referred to as Incineration. • Flame temp: 1500 - 3000ºF• Heat & mass transport, progressive pyrolysis,

gasification, ignition, & burning, with fluid flow. • Usually employs excess oxidizer to ensure max.

fuel conversion• Recoverable Heat is only useful product.



PyrolysisPyrolysis• Thermally degrade material w/o the addition of any

air or oxygen• Similar to gasification – can be optimized for the

production of fuel liquids (pyrolysis oils), with fewer gaseous products (but leaves some carbon as char)

• Pyrolysis oil uses (after appropriate post treatment): liquid fuels, chemicals, adhesives, and other products.

• A number of processes directly combust pyrolysis gases, oils, and char

• Temp. range: 750-1500oF.



GasificationGasification• Emphasis is to form energetic gaseous

products with fewer liquids / solids residues

• Conversion via direct internal heating provided by partial oxidation using substoichiometric air or oxygen.

• Also indirect heating methods (externally fired burners) or autothermal methods (exothermic reducing reactions )

• Temp. Range: 1300 - 1500ºF.• Utilizes a reactant• Often used with pyrolysis to complete

gasification of pyrolytic oils and chars



Process ParametersProcess Parameters• Product composition can be changed by temp, pressure,

speed of process, and rate of heat transfer. • Lower temp./fast pyrolysis temps -- more liquid products• High temperatures produce more gases• Higher pressures can increase reaction rates/ +scalability • Pyrolyzing/gasifying media can be varied by using

hydrogen and/or steam.• Hydrogen

Enhances chemical reduction processes Suppresses oxidation of carbon in feedstock Inhibits formation of dioxins and furans

• Water or steam Increase porosity of char-activated carbon (charcoal) Change the resultant gases and vapors. Can use lower temperatures but higher pressures than “dry”

processes.



SOLID FUEL(MSW, Biomass, etc)

GASIFIER

CYCLONE

GASCOOLER

FLY ASH

AIR, Steam, Pure oxygen, etc.

ASH ANDBED MATERIAL

CLEAN SYNTHESIS OR PRODUCER GAS

(FOR UTIILIZATION)

GAS CLEAN-UP

General Gasifier

Source: Carbona Coporation



Gasification SchematicGasification Schematic



SOLID FUEL(MSW, Biomass, etc)

BED MATERIAL

GASIFIER

CYCLONE

GASCOOLER

WATERFROMHRSG

FLY ASH

AIR

GAS TURBINE

STACKFROM GAS

COOLER

TO GASCOOLER

STEAMTURBINE

CONDENSER

BOOSTERCOMPRESSOR

AIR

STEAM

ASH ANDBED MATERIAL

STEAM TOHRSG

CLEAN PRODUCT GAS

Turbine Exhaust

AIR

HEAT RECOVERYSTEAM GENERATOR

GAS CLEAN-UP

Gasifier (IGCC)

Source: Carbona Coporation



Other example (BRI)

Patent 5,821,111 (1998) Bioengineering Resources, Inc.



Gas-Phase ProductsGas-Phase Products• CO, H2, CH4, O2, N2, H20, CO2 + more minor species

• Majority of processes surveyed utilize post-combustion of gaseous for electricity/heat production

• Post combustion of gaseous products will produce products similar to those found in typical combustion (NOx, CO, hydrocarbons, etc.)

• Easier to clean than typical combustion Exhaust volumes are smaller (less/no O2/air) Pyrolysis oil formation – 80%, less than 20% gases Low molecular weight species (CH4 power plants,

CH4 or H2 engines) Cl, SO2, metals scrubbed prior to combustion



Synthesis GasSynthesis Gas

• Mixture of CO and H2 that can be produced from a variety of sources

• The use of different reactants and process conditions in gasification allows the gas phase composition or the CO and H2 ratio to be varied

• Can be used to produce fuels, chemical products, feed gas for low temperature biochemical processes

• Direct process exhaust is essentially eliminated• Synthesis gas should be scrubbed prior to secondary

processing



Catalytic CrackingCatalytic Cracking• Pyrolysis with catalytic cracking of oils • Utilized in oil refineries on polymeric wastes to

produce liquid fuels• Plastic Energy, LLC is siting a facility in California

using same technology as Zabrze, Poland facility (established in 1997)

• Ozmotech (Australia) installing similar facilities in Spain and Australia



Catalytic CrackingCatalytic Cracking

• Planning to process waste plastics (numbers 2,4,5, and 6).

• ~95% will be film plastics (resins 2 and 4 or HDPE and LDPE)

• PVC and PET will be hand sorted at MRF

Plastic Energy LLC Facility




• Baled plastic delivered from MRF• Washed in mechanically stirred flotation tank (any

inadvertent PVC should sink)• Cleaned plastic is melted ~ 365 ºF

• Flows to reactor and introduced to catalyst, heated to ~600 ºF• Crude oil is formed which is distilled to gasoline and very

low sulfur diesel component • Gasoline used onsite for process energy, • Diesel product sold






Shred & clean plastic

Melt plastic

Reaction Distillation

Low Sulfur Diesel Product

Generator Electricity Gasoline

Baled Plastic

Gas Heat

Source: Larry Buckle Plastic Energy, LLC



Catalytic CrackingCatalytic CrackingPlastic Energy LLC Facility

Product Mass (%)

Gallons/ton feedstock

Gallons/day (50 t/day)

Gallons/day (100

t/day)

Diesel 85 242 12,100 24,200

Gasoline 14 45 2,250 4,500

Light hydrocarbons

1 (vapor)



Plasma Arc SystemsPlasma Arc Systems

• Heating Technique using electrical arc

• Developed for treating hazardous feedstocks

• Contaminated soils

• Low-level radioactive waste

• Medical waste

• Used in some metals processing

• Good for creating molten ash (slag), so is used for incinerator ash melting and stabilizing in Japan

• One Commercial scale facility for treating MSW in Japan




• Can be used in pyrolysis, gasification, or combustion systems

– Depends on amount of reactive oxygen or hydrogen fed to reactor

• Air or inert gas is passed through electric arc creating ionized plasma

• The plasma can reach temperatures of 9,000 – 27,000ºF;

• Gas temperature in the reactor chamber (outside of the arc itself) can reach 1,700 – 2,200ºF; and

• The molten slag is typically around 3,000ºF.

• Will create producer/synthesis gas if operated as gasifier

• Plasma systems can require large amounts of electricity




RCL Plasma – Recoverable Energy EstimatesNo air/oxygen used in gasifier

Units

Energy at exit of gasifier

Gas furnace (20% conversion

efficiency)

Reciprocating engine (35% conv. efficiency)

Gas turbine Combined Cycle

(45% conv. efficiency)

(MMBTU) 9726 1945 3237 4099

Less Electricity to power Torch (MMBTU) -1895 -1895 -1895

Electricity for Export (kWh)16 434 712

Net efficiency to electricity (%) 0.5 14.3 23.5

Power Export- (500t/day input) MWe 0.34 9 15

Electricity production Technology



Plasma Arc SystemsPlasma Arc Systems•Hitachi Metals/Westinghouse Plasma

•Commercial scale plant at Utashinai Japan

•200 tons per day feed input

•~50% is MSW

•~50% Auto shredder residue (ASR)

•Energy for Plasma torches is less because

•ASR is more energetic fuel

•Operates with air injection to reactor in amount ~ 40% of stoichiometric requirements

•This is a ‘plasma assisted’ air blown gasifier




Compound Units Amount

Dioxin ng-TEQ /(Nm3) < 0.01

SO2 ppm <20

HCl ppm <30

NOx ppm <50 (catalyst present)

Particulate matter g/(Nm3) <0.01

Utashinai Plant Emissions (reported by Westinghouse Plasma)



Thermochemical ProductsThermochemical Products

• Fuel gases Internal/external combustion engines Fuel cells Other prime movers

• Liquid Fuels Methanol Fischer-Tropsch (FT) liquids Hydrogen Synthetic ethanol



Thermochemical ProductsThermochemical Products

• Chemicals Ethylene (recycling of plastics) Ammonia based fertilizers Substitute petroleum products Adhesives and resins Food flavorings Pharmaceuticals Fragrances

• Gas phase components for Biochemical Processes



Pyrolysis OilsPyrolysis Oils• Complex mixtures of hydrocarbons

Alcohols, aldehydes, ketones, esters, water, etc

• Can be combusted on site in boilers and engines Lower heating values depending on feedstock

• Chemical uses Phenol species, acetaldehyde, formaldehyde, aromatic

chemicals Wood waste – fragrances, adhesives, resins, food

flavorings, pharmaceuticals

• Dioxins and Furans can concentrate in pyrolytic oils 80-90% of total dioxins/furans Scrubbing 99.84% in removal of Cl prior to

condensation Still examining some data in this area



Commercial StatusCommercial Status

• Thermochemical processes more widely applied to MSW in Europe and Japan

• Large-Scale thermochemical processes used since the 1800s

• Many techniques developed for coal processing TyssenKrupp Uhde has ~100 gasifiers most for coal

• Most Waste facilities operate below 200 tons per day

Some will have higher capacity



Commercial Status IICommercial Status II

• SVZ facility at Schwarze Pumpe in Germany one of the largest facilities 450k tpy solid waste & 55 tpy liquid waste.

• Mitsui & Takuma (licensees Siemens gasif. + pyrolysis)

Plants operating since 1990s, others planned or constructed.

• Nippon Steel Dozen plants 80 to 450 tpd, most operational. Two plants 100 and 450 tpd capacities since late

1970s.

• Ebara/Alstom 450 tpd facility in place. 7 plants either operating, commissioning, and

planned. 1,500 tpd plant in Kuala Lumpur, Malaysia May

2006.



Commercial Status IIICommercial Status III

• A number of Identified Plants did have issues in commissioning, operating or financially

• Brightstar• Fürth, Germany plant had accidentSiemens abandoned the European market

• Karlsruhe, Germany facility - Thermoselect



Pre-Conclusions -ThermochemicalPre-Conclusions -Thermochemical

• Pyrolysis/gasification appears to be technically viable for electricity production

• Recommend CIWMB further investigate/evaluate processes using synthesis gas for fuel or chemical production where post combustion is not required

• Use of thermochemical processes seems to be expanding but process validation is important

• Suggest AB2770 definition for gasification be modified to be more scientifically correct

• Did not examine costs



Biochemical ConversionBiochemical Conversion

• Biochemical conversion- – lower temperature and slower rates compared to

thermochemical methods

– Generally, higher moisture feedstocks are preferred

– Biodegradable components only

» ~None of the current waste plastic stream

» Lignin components of biomass are not degradable anaerobically




• Aerobic (with oxygen)– Composting operates primarily in this mode

– Stabilizes/degrades material faster than if Anaerobic

– Only biochemical mode for lignin degradation (and is very slow)

• Anaerobic (without Oxygen)– Principal biological process occurring in landfills




• Anaerobic decomposition– Biodegradable material only (lignin does not degrade

anaerobically)

– Polymer carbohydrate needs to be broken up into simpler molecules (sugars). Hydrolysis accomplishes this

– Facultative and Fermentive bacteria/yeasts produce

» Biogas (~ 50-65% methane, balance CO2, + small amounts of impurities): Anaerobic Digestion - AD

» Ethanol (and/or other chemicals): Fermentation




• Fermentation route to ethanol and other chemicals

– For sugars and starches is fully commercial (wine, beer, corn (grain) derived ethanol)

– Not yet commercial for cellulosic biomass (most MSW biomass is cellulosic)

» Because of expense and difficulty of Hydrolysis

» Must Hydrolyze cellulose/hemicellulose to sugars and organic acids

» Then yeast ferments the sugars



Biochemical ConversionBiochemical Conversion• Hydrolysis Methods

– Hydrothermal

» Hot water, maybe high pressure

» Steam or Ammonia explosion

– Enzymatic

» Cellulase enzymes to de-polymerize the cellulose

» Currently expensive but believed to be most economical route in future

» Intensive research and engineering of microbes ongoing in public and private institutions world wide

– Acid

» Dilute or Concentrated – Technologically mature

» Currently more economical than enzymatic



Concentrated Acid HydrolysisConcentrated Acid Hydrolysis

Feedstock Size Reduction

1st Stage Hydrolysis

2nd Stage Hydrolysis

LigninSteam/ElectricityGeneration

EthanolConcentration

GypsumNeutralization/Detoxification

Fermentor

Sugars

CelluloseDecrystallization

Water

Water

Acid Reconcentration

Concentrated H2SO4

Acid/sugar separation

Source: http://www.ott.doe.gov/biofuels/concentrated.html)



Biochemicals (fermentative route)Biochemicals (fermentative route)

Source: Arkenol



FermentationFermentationAfter Hydrolysis

Carbohydrate + Cell mass → Ethanol + CO2 + More cell mass

Under best circumstances, mass yield of Ethanol is 51% of mass of input carbohydrate

Accounting for microbe cell growth, best yield in practical systems is ~ 46% (mass basis)

Recall, the lignin component does not participate



Fermentation of components of MSW Fermentation of components of MSW

• Using Hydrolysis to yield sugars and organic acids

– Masada– Arkenol – Waste to Energy (Genahol)– And others

• Using Thermal gasification to depolymerize the cellulose

– BRI– Novahol– And others?

Companies;



Masada ‘OxyNol’ Masada ‘OxyNol’

• Middletown, N.Y., Permitted (start construction?)

Unit operations include

• MRF

• Feedstock Preparation (shredding and drying)

• Acid Hydrolysis Unit (single stage)

• Fermentation and Distillation Units

• Focusing on MSW feedstocks



Masada ‘OxyNol’ Masada ‘OxyNol’

• 230,000 tons per year MSW• 70,000 dry tons per year Biosolids

Products• Ethanol (25 -35 gallons per wet ton feedstock)• CO2• Recyclables (from up-front separation)• Gypsum

“majority of revenue stream for a typical OxyNol facility comes from tipping fee, not products produced from waste”

Middletown Facility



Arkenol Arkenol

• Develops Biorefineries

• Cellulose to ethanol via concentrated acid hydrolysis (2-stage)

• Commercial scale plant in Japan using waste wood feedstock

• 67 gallons ethanol per dry ton of feedstock (~equivalent to Masada yield on wet basis)



Waste to Energy w/ GenaholWaste to Energy w/ Genahol

Anaerobic digestion block diagramAnaerobic digestion block diagram

Source: Brelsford Engineering, Inc

• 2-Stage Dilute Acid Hydrolysis

• Brelsford Engineering Proc.

• Attempting validation plant in Santa Maria, CA

• MRF residue– Biomass to ethanol

– Lignin & Plastics thermal CT for heat and power

• Expect Similar Yields



BRI Energy, LLC BRI Energy, LLC

• Bioreactor ferments waste and synthesis gases– Ethanol

– Hydrogen

• Proposing to gasify biomass and other components in MSW and fermenting the producer gas to ethanol




Source: patent 5,821,111 (Gaddy, 1998). Bioengineering Resources, Inc




• Yield from biomass feedstock is potentially greater than acid/enzymatic hydrolysis because lignin is converted in gasifier (Claim 75 gallons ethanol/dry ton)

• Because of bacteria and bioreactor characteristics, fermentation stage is quick

• Claim material is gasified and fermented to ethanol in less than 1 hour. (Std. sugar fermentation ~ 36-48 hrs.)

• Plastics, tires, waste oils can be processed to ethanol in this system



NovaholNovahol

• Also promoting ethanol from fermentation of synthesis gas

• Focusing on wood waste right now (wood from bark beetle infestation)



Anaerobic Digestion producing BiogasAnaerobic Digestion producing Biogas

• Principle process occurring in Landfills

• Many waste water treatment plants use AD

• Extensive development and use of this technology in Europe

– Policies; GHG reduction, Total Organic Carbon restrictions in Landfill stream.



Anaerobic Digestion Block DiagramAnaerobic Digestion Block Diagram

Particulate Organic Material

Sugars, Amino acids, Organic acids

Acetate, Hydrogen

MethaneCO2

HYDROLYSIS

ACETOGENESIS

METHANOGENESIS

* Adapted from Mata-Alvarez, J. (2003)]



Anaerobic Digestion producing BiogasAnaerobic Digestion producing Biogas

• Systems can be classified;– Low or High Total Solids

LS< 15% TS or > 85% moisture (‘wet’ systems)

HS range between 20-30% TS or 70-80% moisture (‘dry’ systems)

– Single Stage digester

– Two or multi-stages

– Batch

• Optimum Temperatures– Mesophilic (85 – 95 ºF)

» Slower reaction – longer retention times

– Thermophilic (~120- 150 ºF)

» Faster but requires more heat energy



Single Stage Low Solids AD (Waasa Process)Single Stage Low Solids AD (Waasa Process)

Pre-Chamber

Inoculationloop

Heavies

Biogenic fraction of MSW

Composting

Recycle process water

Make-up water Water

treatment

Biogas

PULPING METHANIZATION

DEWATERING

10-15% TS

Heat addition


Hydrolysis, acetogenesis, and methanogenesis occur in a single vessel.



Single Stage – High Solids ReactorsSingle Stage – High Solids Reactors

Feed

Digested paste

Dranco

Feed Digested paste

Inoculum loop

Kompogas

Feed

Biogas

Digested paste

Biogas recirculation

provides inoculant

Biogas

Biogas

Valorga


Less pre-treatment, though high solids pumps cost more

Some systems can accept Unsorted MSW (requires some size reduction and removal of large items) – though yield suffers

‘Plug Flow’ reactors, therefore require method to inoculate fresh feed



2-Stage AD Schematic2-Stage AD Schematic

Composting

Make-up water

Waste and WaterTreatment(and/ or compost and liquid fertilizer)

Biogas

Dewatering

Liquid

Liquid Recycle

SolidFeed

STAGE 1(hydrolysis)

STAGE 2(methanogenesis)

Note: 2nd Stage could be reactor type;CSTR,UASB,Fixed Film,(among others)


Opportunity to optimize hydrolysis and methane production separately

First Stage can be Low or High Solids, continuous or batch loading

Second stage is generally Low Solids



Anaerobic Phased-Solids DigesterAnaerobic Phased-Solids Digester

Source: Professor Ruihong Zhang

High Solids Hydrolysis stages operate in Batch Mode; Timing is phased for uniform methane production rate

Second stage is generally Low Solids

Best with source separated biogenic fraction of MSW



Anaerobic Phased-Solids DigesterAnaerobic Phased-Solids Digester

Source: Karl Hartman, UCD

Model results for lab-scale APS digester

0

2

4

6

8

10

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16Time (Days)

Me

than

e P

rod

uc

tio

n (

L/d

ay

)

H-I H-II H-III H-IV

Total

Methane production due to individual phased batch hydrolysis reactors.

Overall methane production is smoother.

This system is being piloted.



AD in Europe AD in Europe

• 86 facilities larger than 3300 ton per year capacity

• Total installed capacity of 2.8 million tons waste per year

• Spain will be treating 7% of biodegradable components of MSW by end of 2004 (13 facilities, average 70,000 tons per year).



AD Capacity in EuropeAD Capacity in Europe

0.0

0.5

1.0

1.5

2.0

2.5

3.0

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

Cap

acit

y (m

illio

n t

on

s/y)

*

*Data were projected for 2004

Solid Waste Anaerobic Digester Capacity in Europe

De Baere, L. (2003).

Facilities with > 10% of feedstock coming from MSW components.

Many co-feed with animal manures, biosolids

~90% of capacity is composed of Single Stage systems



Biochemical ConversionBiochemical ConversionCompany Name Corp. Headquarters

Process Name

Process TypeNumber of Facilities

Kompogas Glattbrugg, Switzerland Kompogas AD 25Valorga Montpellier, France Valorga AD 13Organic Waste Systems Gent, Belgium Dranco AD 13CiTec Finland/Sweden Waasa AD 11BTA (Canada Composting in North America)

Munich, Germany (Ontario, Canada)

BTA AD10

Wright Environmental Mngmt.

Ontario, Canada In vessel Composting 6Linde-KCA-Dresden Dresden, Germany AD & composting

(MBT) 3Eco Tec Finland WABIO AD 3Arkenol Ethanol via Acid

Hydrolysis 1Arrow Ecology Haifa, Israel Arrow Bio AD 1Wehrle Werk AG Emmendingen, Germany Biopercolat AD ?U-plus Umweltservice Ettlingen, Germany ISKA MBT / AD ?Onsite Power Systems Camarillo, CA APS (UC Davis) AD Pilot &

ProposedMasada Resource Group Birmingham, Alabama CES Oxynol Ethanol via Acid

HydrolysisPilot &

ProposedWTE (w/ Genahol) Santa Maria, CA Genahol/BEI Ethanol via Acid

Hydrolysis Proposed



Biochemical ConversionBiochemical ConversionPre-ConclusionsPre-Conclusions

• Technically viable for some components of waste stream

• Costs (and perhaps low public awareness) impede development



Alternative Conversion Alternative Conversion Technologies – Technologies –

Environmental ImpactsEnvironmental Impacts



Present SituationPresent Situation

• Landfills produce mainly CH4, CO2

• Trace gas constituents (BTX, H2S, vinyl chloride)

• Landfills largest source of GHG methane emissions --- roughly 1/3rd of total

• 3,000 landfills in California, 311 active• 51 convert gas to energy currently –211 MW• Another 26 planning to use energy – 29 MW• 70 landfills flare landfill gas (66 MW eq.)• Remainder (164) vent to atmosphere (31 MW

eq.)



Thermochemical Process EmissionsThermochemical Process Emissions• Intermediate gases/oils may contain CO, VOCs,

HCl, H2S, dioxins/furans

• Many processes surveyed use intermediate gas combustion for electricity/heat production

• Post combustion of gaseous products will produce products similar to those found in typical combustion (NOx, CO, hydrocarbons, etc.)

• Easier to clean than typical combustion Intermediate gas volumes are smaller (less/no

O2/air) Low molecular weight species (CO, H2, CH4) Cl, S, PM can be scrubbed prior to combustion



Dioxin/Furans IDioxin/Furans I

ClCl ClCl

ClClClCl

OO

OO

ClCl ClCl

ClClClCl OO



Dioxin/Furans-Formation IIDioxin/Furans-Formation II

• Poor gas-phase mixing• Low combustion temperatures• Oxygen-starved conditions• Temperatures 480ºF to 1290ºF• Formation from Wastes

Feedstocks with high levels of Cl and CuOxygen content of feedstock 25-45%



Dioxin/Furans-Studies Dioxin/Furans-Studies

• Weber and Sakurai, Chemosphere, 45, 1111-1117 Industrial Light Shredder (5% Cl) & Refrigerator

shredder (1% Cl), w/ 3-6% Cu 90% PCDD/F in pyrolysis oils (1,500-10,000 ng/g)

• Mohr et al., Chemosphere, 34, 1053-1064 Feedstock contained chloro-benzenes, phenols, PCBs PCDD/F 1,983 ng/g in oil for 3,485 ng/g feedstock

• Miranda et al., Polymer Degrad & Stability Vol. 73, pp 47-67, 2001 Commingled plastics with PVC (7.9%) Cl volatilized at 680 ºF to HCl NaOH scrubber removed 99.84% Resulting pyrolysis oil contained 12 ppm Cl



Pollution ControlsPollution Controls

• Cold-quenching – dioxins/furans, acid gases• Baghouse, ESP – particulate matter• Catalytic/thermal incineration - dioxins/furans,

VOCs, CO • Flame temperature control/catalytic reduction –

NOx

• Scrubber – Acid gases• Carbon filters, carbon injection, duct sorbent

injection – dioxins/furans, VOCs



Improvements in Air Pollution Improvements in Air Pollution ControlControl

Emissions from Large MSW Incinerators Pollutant 1990

Emissions 2000

Emissions Percent

Reduction Dioxins/Furans, total mass basis 218,000 g/yr 679 g/yr 99+ Dioxins/Furans, Toxic equivalent quantity basis

4,260 g/yr 12.0 g/yr 99+

Mercury 45.2 tpy 2.20 tpy 95.1 Cadmium 4.75 tpy 0.333 tpy 93.0 Lead 52.1 tpy 4.76 tpy 90.9 Particulate Matter 6,930 tpy 707 tpy 89.8 Hydrochloric Acid 46,900 tpy 2,672 tpy 94.3 SO2 30,700 tpy 4,076 tpy 86.7 NOx 56,400 tpy 46,500 tpy 17.6 Source: United States Environmental Protection Agency Memorandum, “Emission from Large MWC Units at MACT Compliance,” June 20, 2002



Emissions DataEmissions DataEmission Results for Various Pyrolysis/Gasification Facilities/Technologies (mg/Nm3

unless noted) PM NOx CO TOC VOC SO2 H2S Dioxins/furan

(ng/Nm3) HCl HF

Balboa Pacific 68 ppm 36 9 13 6 Brightstar 1.6-10 40-96 440-625 0.05 <0.1 <2 0.0331 <1.0 0.59 GEM 3 262 8 6 79 0.02 4 ND Organic Power 3 168 5 5 8 0.07 5 0.2 PKA 2.3 54 38 2.3 7.7 0.02 2.3 0.15 Pyromex 135 38 0.5 20 0.005 1 0.03 RCR-Thermsave 183 8 6 41 0.02 4 0 RGR Ambient 3.6 75 6.1 3.4 7.7 6.3 0.23 Serpac 4.2-5.2 61-189 0.5-2.5 0.2-0.5 0.0-5.6 0.002 1.7-5 <0.1 Technip 3 180 10 2 5 0.001 5 0.2 Thermoselect 0.0007-

0.0011

Thide-Eddith 470 50 <15 <200 30 <1 TPS 3-7 200-300 2.5-5 5-15 0.013 0.6-2 <0.1 Notes: PM = particulate matter, TOC=total organic carbon, VOC=volatile organic carbon, ND=not detect



Emissions Data IIEmissions Data II

Metal Gaseous Emissions Results for Various Pyrolysis/ Gasification Facilities/Technologies (mg/Nm3 unless noted)

As Cd Cr Cu Pb Mn Hg All /other metals

Brightstar 0.0051 <0.0002 0.013 0.0051 0.0080 0.072 GEM ND ND 0.07 Organic Power 0.004 0.03 PKA 0.002 0.002 0.07 Pyromex 0.002 0.07 RCR-Thermsave ND ND 0.07 RGR Ambient 0.016 0.35 Serpac 0.05 Technip 0.02 0.02 0.2 TPS <0.004 0.005 0.008-0.05

Notes: As=Arsenic, Cd = Cadmium, Cr=Chromium, Pb=Lead, Hg=Mercury, ND=not detect



Solid Waste DataSolid Waste Data

Ash Residuals and Leaching Data for Various Pyrolysis/ Gasification Facilities/Technologies (mg/l unless noted) Units As Ba Cd CN Cr Cu Pb Mn Ni Hg Zn All

metals BalPac mg/l 0.05 0.37 0.1 0.01 0.58 Compact Power

m/kg 4 0.1 289

Ebara/Alstom (glass granulate)

mg/l <0.001 <0.01 <0.005 0.056 0.013 <0.01 <0.0005 0.05

GEM ppm <100 <100 1330 406 <100 109 <100 Nexus mg/kg <1 <0.05 <0.05 <1 <0.05 PKA mg/l 0.002 <0.001 <0.005 <0.01 0.072 0.014 <0.002 0.014

Notes: As=Arsenic, Ba=Barium, Cd = Cadmium, CN=Cyanide, Cr=Chromium, Cu=Copper, Pb=Lead, Mn=Manganese, Ni=Nickel, Hg=Mercury, Zn=Zinc, ND=not detect



Environmental Impact SummaryEnvironmental Impact Summary• All waste disposal methods carry environmental

risks• Proper design of waste conversion processes must

address air emissions, liquid and solid residues• Characterization and pre-sorting of feedstocks

can reduce emissions • Process and pollution control technologies can

minimize environmental impacts, but must be carefully designed and operated

• Overall environmental impacts of well-designed alternative waste conversion technologies are equal to or less than current practice of landfilling



Conclusions for Alternative Conclusions for Alternative Conversion TechnologiesConversion Technologies



Problem at Hand?Problem at Hand?

• Non-sustainable environment of landfilling of 37 million tons of material annually

• Landfill gas impacts & other factors

• Landfill expansion becoming more difficult and not beneficial to society

• Source reduction, recycling, alternative conversion technologies



Available FeedstocksAvailable Feedstocks• 2370 MWe or 60 million barrels of oil• Paper and Cardboard

Landfill 10 million tons, Recycle 4-5 million tons (30%) 44% of energy value

• Plastics 2nd high energy content – 30% of total 11% of landfilled mass and 22% of landfilled volume Growing rapidly and recycling rates are relatively low Only thermochemical can process

• Biochemical Feedstocks Food waste Green/paper waste

• Contaminants Chlorine containing materials (PVC) Pigments in paper, other metal contaminants



Thermochemical ProcessesThermochemical Processes• Pyrolysis - Thermally degrade material w/o the addition of any air or

oxygenCan be used to maximize oil productionMany processes use post-combustion for electricity

• Gasification - Conversion via direct internal heating provided by partial oxidation using substoichiometric air or oxygen (Hydrogen or steam)Indirect heating methods (externally fired burners) or autothermal methods

(exothermic reducing reactions )Can be utilized to produce synthesis gases

• Synthesis gas produce chemical/fuel without combustion• Combust for electricity -produce gaseous products similar to

combustionLower exhaust volumesLower molecular weight speciesScrubbing prior to full combustion or use in chemicals/fuels



Thermochemical Processes IIThermochemical Processes II• Have the greatest potential to process the whole MSW

organic stream• More commercial in Japan and Europe• Some plants have experienced problems – Technology must

be proven sound• Study did not cover economic viability• Suggest AB2770 definition for gasification be modified to

be more scientifically correct• More formal vendor should be conducted • Need to consider possibility of fuels/chemical instead of

electricity – perhaps work in this directionSynthetic ethanol, F-T diesel, hydrogenEthylene, fertilizers, petroleum products, adhesivePyrolysis Oils – fragrances, adhesives, resins, Pharmaceuticals



Biochemical ProcessesBiochemical Processes

•Fermentation, anaerobic & aerobic digestion

•Carried out at lower temps. & reaction rates

•Utilize biodegradable feedstocks



Environmental ConclusionsEnvironmental Conclusions• Air Emissions – Thermochemical process

– Can use synthesis gas for fuel/chemical w/o combustion

– Post-combustion – similar products to combustion– Little for no oxygen/air – reducing environment– Small air volume– Low molecular weight species – cleaner to combust– Less costly but similar emissions control

• Solid Waste– Thermochemical processes concentrate but do not

create metallic species

• Liquid Waste– Spent acids from biochemical processes, spent

scrubber solutions



Socio-economic ImpactsSocio-economic Impacts

• Full Life Cycle Analysis should be used in comparing benefits/liabilities

• Potential Resource – 60 million barrels oil or 2370 MW electrical power

• Provide diversity of product markets

• Extension of landfills

• Impacts on recycling

• Environmental impacts



RecommendationsRecommendations

• Formal vendor evaluation• Improve Characterization of MSW

Elemental analysis, heating value, biochemical properties

• Improve estimates of waste generation• Collect emissions data for Thermochemical• Investigate legislation for further increase in

landfill diversion• Co-fund alternative conversion projects• Study future landfill costs• Study the feasibility of “zero waste” through

recycling or source reduction

Documents

Center for Environmental Research and Technology University of California, Riverside University of California, Davis Performance and Environmental Impact