Performance and Environmental Impact Evaluations of Alternative Waste Conversion Technologies in California

1

• Performance and Environmental Impact Evaluations
  of Alternative Waste Conversion Technologies in
  California
• Public Workshop
• April 14, 2004

2
Introductions

• California Integrated Waste Management Board
• Fernando Berton Project Coordinator

3
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

4
Materials 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

5
CIWMB 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

6
CIWMB 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

7
CIWMB 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

8
CIWMB Policy Recommendations

• Adopted April 2002
• Conversion Technology Definition
• Conforming definition to transformation
• Findings
• Level of credit
• Regulatory and Permitting

9
AB 2770 Penultimate Version

• Administration-sponsored
• Definition, findings, level of credit
• Conforming changes for counting diversion
• Provisions on CEQA, testing residue, etc.
• RD program
• Lifecycle costs/benefits
• Feedstock amenability with different
  technologies
• Small-scale grant/RD program

10
AB 2770 Chaptered Version

• Gasification Definition
• Lifecycle and market impacts - RTI
• Technical evaluation UC contract
• Risk assessment issues OEHHA contract
• Report to Legislature

11
Performance and Environmental Impact Evaluations
of Alternative Waste Conversion Technologies in
California University of California,
Riverside College of Engineering Center for
Environmental Research and Technology University
of California, Davis Sponsored by California
Integrated Waste Management Board
12
Technology Identification/Evaluation

• Definitions
• Analysis of performance characteristics
• Technical limitations
• Commercial status
• Types of feedstocks and quality (moisture)

13
Processes Evaluated

• Thermochemical Processes
• Gasification
• Pyrolysis
• Catalytic Cracking
• Plasma Arc
• Biochemical Processes
• Fermentation
• Digestion
• Hydrolysis

14
Product 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

15
Environmental Impacts

• Emissions and emissions sensitivity to feedstocks
• Residues (hazardous and non-hazardous)
• Nuisance factors (noise, dust, traffic)
• Other environmental impacts

16
Initial Work

• 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

17
Technical 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

18
Purpose 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

19
Project Timing

• Public Workshop discuss preliminary findings
• Working Draft sent to Technical Advisory Board
• Comments expected by end of April
• Completed final draft reported by early May and
  provided to Board for May meeting
• Posted 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
  approval
• Release of Final Report will be delayed to July
  Board meeting if comments remain to be addressed

20
Feedstocks for Alternative Conversion Technologies
21
MSW 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

22
1999 Waste Stream Characterization
23
Waste Distribution Mass/Energy
24
Energy Equivalence

• 2370 MW of electrical power
• 5 of states capacity and 6 of consumption
• 60 million barrels of crude oil
• _at_ 37 barrels ----- 2.2 billion

25
Diversion 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 states 30 biomass
  power plants
• Approximately 15 million wet tons ( 8 MBDT) of
  organics sent to landfill (CD wood, green waste,
  food waste, and other)

26
Diversion 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

27
Diversion 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

28
Waste Reduction

• Packaging and containers
• 32 of MSW generated, 28 of disposed MSW
• European Policies
• 1994 EC Directive to take measures to reduce
  package waste
• 1991 German Extended Producer Responsibility
• Manufacturers take back container packaging
• Individual companies or central system
• US2.25 per month
• Packaging 90 recovered and 80 recycled
• Uncertain how readily such programs could be
  implemented in California

29
MSW Combustion aka incineration

• 130 million tons worldwide at over 600 facilities
• Roughly 75 of waste in Japan
• 167 large facilities in US ---- 2/3rds on east
  coast
• 3 in California
• Poor perception by public
• Incinerators have decreased emissions
  considerably

30
Feedstocks for Alternative Conversion 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

31
Waste Distribution Mass/Energy
32
Biochemical Process Feedstocks

• Biodegradable components of the landfill stream
  include
• Food wastes
• Leaves, grass, trimmings
• Paper/cardboard
• Wood waste
• Biodegradation varies in rate and degree

33
Biochemical Process Feedstocks

• Biodegradation is not complete
• Lignin fraction will not degrade anaerobically
• Lignin 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

34
Biochemical Process Feedstocks
Biogas Potentials

• 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)

35
Biochemical Process Feedstocks
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)
36
LCA/ 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

37
Recommendations

• Improve characterization of waste in conjunction
  with waste characterization studies
• Proximate, ultimate, and elemental analysis
• Ash, metals, toxic congeners
• Higher heating values (HHV)
• Characterize protein, carbohydrates, and fats in
  typical food wastes

38
Alternative Conversion Technologies Processes
and Products
39
Conversion Processes to Evaluate

• Physicochemical
• Biodiesel
• Distillation

40
(No Transcript)
41
Combustion

• 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.

42
Pyrolysis

• 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.

43
Gasification

• 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

44
Process 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.

45
General Gasifier
Source Carbona Coporation
46
Gasification Schematic
47
Gasifier (IGCC)
Source Carbona Coporation
48
Other example (BRI)
Patent 5,821,111 (1998) Bioengineering Resources,
Inc.
49
Gas-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

50
Synthesis 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

51
Catalytic 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

52
Catalytic Cracking
Plastic Energy LLC Facility

• 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

53
Catalytic Cracking
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

54
Catalytic Cracking
Plastic Energy LLC Facility
Source Larry Buckle Plastic Energy, LLC
55
Catalytic Cracking
Plastic Energy LLC Facility
56
Plasma 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

57
Plasma Arc Systems

• 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

58
Plasma Arc Systems
RCL Plasma Recoverable Energy Estimates No
air/oxygen used in gasifier
59
Plasma 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

60
Plasma Arc Systems
Utashinai Plant Emissions
(reported by Westinghouse Plasma)
61
Thermochemical Products

• Fuel gases
• Internal/external combustion engines
• Fuel cells
• Other prime movers
• Liquid Fuels
• Methanol
• Fischer-Tropsch (FT) liquids
• Hydrogen
• Synthetic ethanol

62
Thermochemical 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

63
Pyrolysis 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

64
Commercial 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

65
Commercial 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.

66
Commercial Status III

• A number of Identified Plants did have issues in
  commissioning, operating or financially
• Brightstar
• Fürth, Germany plant had accident
• Siemens abandoned the European market
• Karlsruhe, Germany facility - Thermoselect

67
Pre-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

68
Biochemical 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

69
Biochemical Conversion

• 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

70
Biochemical Conversion

• 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

71
Biochemical Conversion

• 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

72
Biochemical 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

73
Concentrated Acid Hydrolysis
Acid/sugar separation
Source http//www.ott.doe.gov/biofuels/concentrat
ed.html)
74
Biochemicals (fermentative route)
Source Arkenol
75
Fermentation

• After 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

76
Fermentation of components of MSW
Companies

• 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?

77
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

78
Masada OxyNol
Middletown Facility

• 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

79
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)

80
Waste to Energy w/ Genahol

• 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

Anaerobic digestion block diagram
Source Brelsford Engineering, Inc
81
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

82
BRI Energy, LLC
Source patent 5,821,111 (Gaddy, 1998).
Bioengineering Resources, Inc
83
BRI Energy, LLC

• 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

84
Novahol

• Also promoting ethanol from fermentation of
  synthesis gas
• Focusing on wood waste right now (wood from bark
  beetle infestation)

85
Anaerobic 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.

86
Anaerobic Digestion Block Diagram
Adapted from Mata-Alvarez, J. (2003)
87
Anaerobic Digestion producing Biogas

• Systems can be classified
• Low or High Total Solids
• LSlt 15 TS or gt 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

88
Single Stage Low Solids AD (Waasa Process)
Biogenic fraction of MSW
PULPING
METHANIZATION
Biogas
Pre-Chamber
10-15 TS
DEWATERING
Inoculation loop
Heat addition
Composting
Make-up water
Heavies
Water treatment
Recycle process water
Hydrolysis, acetogenesis, and methanogenesis
occur in a single vessel.
Adapted from Mata-Alvarez, J. (2003)
89
Single Stage High Solids Reactors
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
Adapted from Mata-Alvarez, J. (2003)
90
2-Stage AD Schematic
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
Adapted from Mata-Alvarez, J. (2003)
91
Anaerobic Phased-Solids Digester
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
Source Professor Ruihong Zhang
92
Anaerobic Phased-Solids Digester
Model results for lab-scale APS digester
Methane production due to individual phased batch
hydrolysis reactors. Overall methane production
is smoother. This system is being piloted.
Source Karl Hartman, UCD
93
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).

94
AD Capacity in Europe
Solid Waste Anaerobic Digester Capacity in Europe
Facilities with gt 10 of feedstock coming from
MSW components. Many co-feed with animal manures,
biosolids 90 of capacity is composed of Single
Stage systems
Data were projected for 2004
De Baere, L. (2003).
95
Biochemical Conversion
96
Biochemical ConversionPre-Conclusions

• Technically viable for some components of waste
  stream
• Costs (and perhaps low public awareness) impede
  development

97
Alternative Conversion Technologies
Environmental Impacts
98
Present 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.)

99
Thermochemical 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

100
Dioxin/Furans I
Cl
Cl
Cl
Cl
O
101
Dioxin/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 Cu
• Oxygen content of feedstock 25-45

102
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

103
Pollution 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

104
Improvements in Air Pollution Control
105
Emissions Data
106
Emissions Data II
107
Solid Waste Data
108
Environmental 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

109
Conclusions for Alternative Conversion
Technologies
110
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

111
Available 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

112
Thermochemical Processes

• Pyrolysis - Thermally degrade material w/o the
  addition of any air or oxygen
• Can be used to maximize oil production
• Many 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 combustion
• Lower exhaust volumes
• Lower molecular weight species
• Scrubbing prior to full combustion or use in
  chemicals/fuels

113
Thermochemical 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
  direction
• Synthetic ethanol, F-T diesel, hydrogen
• Ethylene, fertilizers, petroleum products,
  adhesive
• Pyrolysis Oils fragrances, adhesives, resins,
  Pharmaceuticals

114
Biochemical Processes

• Fermentation, anaerobic aerobic digestion
• Carried out at lower temps. reaction rates
• Utilize biodegradable feedstocks

115
Environmental 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

116
Socio-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

117
Recommendations

• 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