Joseph Greene Presentation

8/6/2019 Joseph Greene Presentation

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Plastivida Brazil

June 10, 2008

Joseph P. Greene, Ph.D.Professor

California State University, ChicoChico, CA 95929-0789

Biodegradable and Degradable

Plastics Biodegradation Testing inAerobic Compost and Anaerobic

Environments


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Agenda Research Objectives Products Tested

Results

Compost Environment Chico Green Yard Waste

Chico In-vessel Manure Waste

Vacaville In-vessel Food Waste

Mariposa County In-vessel Municipal Solid Waste (MSW) Laboratory ASTM D-6400

Marine Water Environment

Anaerobic Digestion Environment

Laboratory Quality Tests for Contamination of RecycledPlastics

Conclusions and Recommendations

Questions


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Objectives of Research Evaluate

Performance, degradation rates and environmental impacts of

degradable plastic products in commercially operated compost

facilities and in simulated marine environments.

Testing

Bio-degradation

Compost environment: windrow, in-vessel, and laboratory

locations Marine environment

Anaerobic digestion

Environmental Safety Assessments

Fate and persistence of the by-products and toxicity resultingfrom the degradation

Mechanical and physical properties

Recycled plastics with contamination from degradable plastics


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What does Biodegradable Mean?Can the microorganisms in the disposal system (composting, soil, anaerobic vessel)assimilate/utilize the carbon substrate as food source completely and in a short defined

time period?

CO2 + H2O + Cell biomass

CompleteCompleteCompleteComplete

microbial

assimilation

Specified time

frame.

No residual

residues.

Hydrolytic

Polymer chains with

susceptible linkages

EnzymaticOxidative Oligomers & polymer fragments

Environment soil, compost,waste water plant, marine

Biodegradation: Only ifall fragmentedresidues consumed by microorganisms as

a food & energy source

Define time and environment (disposal

system)

Reference: Dr. Ramani Narayan, Michigan State University, www.msu.edu/~narayan


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Biodegradable versus Degradable Plastics

Biodegradable Plastics Degraded by microorganisms in soil, compost, or marine

environments.

Made from natural materials, e.g.,corn, potato, polylactic acid,

sugar cane, microbes, etc. Made from petroleum products, e.g. modified or polyesters.

Compostable Regulated by ASTM standards- will degrade in compost environment in

less than 180-days. Does not leave any fragments in residue, does not have any heavy metalsor toxins, and will support plant life.

Degradable plastics

Degraded by sunlight, oxygen, or microbes. Oxodegradable, photo-degradable, starch-polyethylene plastics.

Can cause environmental problems. Results in small fragments that can pollute compost, landfill, marine.

Does not degrade as fast as compostable plastics, may leave small

fragments in soil, may not have toxic residuals, may not support plant life.


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Designing products to be degradable or partially biodegradable causes

irreparable harm to the environment

Degradable, biobased, single-use, disposable packaging and consumerplastics, and plastic-paper combination products (non-durable goods)

have serious environmental consequences.

Must ensure complete biodegradability in a short defined time frame

(determined by the disposal infrastructure like composting)

TIME --- ONE GROWING SEASON; MAYBE TWO

DISPOSAL ENVIRONMENT Composting, anaerobic

digestion plants, marine/oceans, soil

DEGRADABLE = Major Environmental Problems

MUST ENSURE COMPLETE BIODEGRADABILITY IN THEMUST ENSURE COMPLETE BIODEGRADABILITY IN THEMUST ENSURE COMPLETE BIODEGRADABILITY IN THEMUST ENSURE COMPLETE BIODEGRADABILITY IN THE

SELECTED DISPOSAL ENVIRONMENT (as per ASTM testSELECTED DISPOSAL ENVIRONMENT (as per ASTM testSELECTED DISPOSAL ENVIRONMENT (as per ASTM testSELECTED DISPOSAL ENVIRONMENT (as per ASTM test

methods and specifications)methods and specifications)methods and specifications)methods and specifications)

Reference: Dr. Ramani Narayan, Michigan State University, www.msu.edu/~narayan


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Definitions Degradable plastics

All plastics are degradable, though the mechanism is different.

Oxidation: plastics degrade in oxygen environment. Anti-oxidants are added topolymers.

UV light: plastics degrade in sunlight. Stabilizers are added to polymers. Heat: polymers can degrade under high temperatures. Stabilizers are added

Oxo-Degradable Pro-degradents are added to increase the rate of oxidation and disintegration of

plastics though NOT biodegradable since microorganisms do not consumethem.

Biodegradable Plastics degrade from microorganisms that consume material but time frame is

not specified.

Can be biobased or petroleum based. Both can be consumed by microorganisms.

Compostable (Most complete definition) Plastics that degrade from microorganisms that consume material in specified

time frame and under specified environmental conditions.

Can be biobased or petroleum based. Both can be consumed by microorganisms.


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Products Tested Compostable (Certified by Biodegradable Polymers Institute- BPI)

PLA Cups, forks, spoons, knives, clamshell containers, lids, and straws

Biobag trash bags

Ecoflex Polyester bags

PHA Bags

Husky Eco Guard biodegradable bags

Sugar Cane Bagasse plates, bowls, and containers.

Oxo-Degradable (NOT certified by Biodegradable PolymersInstitute- BPI)

Natural Value Oxo-degradable Ecosafe Trash Bags Oxo Biodegradable Eco-friendly plastic bag

UV-degradable plastic bags and soda can rings

Control

LDPE plastic trash bag Kraft paper

Cellulose filter paper


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Commercial Compost Environment

Sites

Chico Green Yard Waste

Chico In-vessel Manure Waste

Vacaville In-vessel Food Waste Mariposa County In-vessel Municipal Solid Waste

Materials (Purchased at stores or on-line)

Compostable: PLA lids, Biobag trash bags, Ecoflex Polyester bags, PHA Bags,

Husky Eco Guard biodegradable bags, Sugar Cane Bagasse lids. Oxodegradable: Ecosafe Trash Bags, Eco-friendly plastic bag, UV-degradable

plastic bags

Controls: LDPE plastic trash bag and Kraft paper

Tests Monitored visual disintegration and biodegradation of products after 30, 60, 90,

and 180 day test intervals.

Monitored temperature of air and compost, moisture percentage, pH, compostmaturity, and % solids.


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Chico Green Yard Waste Compost

Pictures (120 days)

OxobiodegradableCompost pile

PLA Container Biobag bag

Incoming trash


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Chico Green Yard Waste Compost Results:

30 days: (Windrow)

No degradation: Oxo-biodegradable plastic trash bags Some degradation: Food waste and PLA cups, forks, spoons,

knives, clamshell containers, lids, and straws, Sugar cane plates

and lids, and Biobag trash bags.

120 days: (Windrow)

No degradation: Oxo-biodegradable plastic trash bags

More degradation: Small fragments of PLA container andstraw, and Biobag trash bags.

Full degradation: no visible fragments- PLA cups, forks,spoons, knives, and lids; sugar cane lids and plates.


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In-vessel Manure and Food Waste Compost

Pictures (120 days)

In-vessel Compost pile

PLA Container Biobag bag

Incoming MSW trashTurning row


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In-vessel Manure and Food Waste Compost

Results

30 days (In-vessel)

Some degradation: Food waste and PLA cups, forks, spoons,knives, clamshell containers, lids, and straws, Sugar cane plates


120 days: (Windrow) More degradation: Small fragments of PLA cups and container,

and Biobag trash bags.

Full degradation: no visible fragments- PLA, forks,spoons, knives, and lids; sugar cane lids and plates.


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NorCal Vacaville In-vessel Compost

Pictures

Compost pile after 30 daysIn-vessel composting with polyethylene cover


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NorCal In-vessel Compost Pictures

Oxodegradable plastic bag Oxodegradable plastic bag UV-polyethylene plastic bag

Mirel PHA plastic bagCorn starch plastic bag Ecoflex plastic bag


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NorCal Vacaville In-vessel Compost Pictures

PLA lids Sugar can lids

Husky Eco-Guard plastic bag LDPE plastic bags

Kraft paper


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NorCal Vacaville In-vessel Compost

Pictures

Compost pile after 30 daysBurlap sacks filled with samples


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NorCal Vacaville In-vessel Food Waste

Compost Results

30 days (In-vessel) September to October 2006


and lids, and Corn starch trash bags.


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NorCal In-vessel Compost Pictures- 30 days




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NorCal Vacaville after 30 days Pictures



Kraft paper


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Vacaville In-vessel Food Waste

Compost Pictures (180 days)

In-vessel Compost pile Sugar cane lidsKraft paper

Compost temperature: 140 +/- 5F Moisture: 40-45%


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Vacaville In-vessel Food WasteCompost Pictures (180 days)

Oxodegradable bag UV-degradable LDPE stretch film control


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Vacaville In-vessel Food Waste Compost

Results

30 days (In-vessel)

60 days: (Windrow)

180 days: (Windrow) March 2007

No degradation: Oxo-biodegradable and UV degradable plastic

trash bags; LDPE control.

Some bio-degradation: Sugar cane lids and Kraft paper control

though samples were very wet and fell apart when moved.

Full degradation: no visible fragments- PHA bag,Ecoflex bag, PLA lids, Biobag trash bags.


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Mariposa County In-vessel MSW Compost

Pictures

ECS In-vessel Compost Method Inside chamber with samples


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Mariposa In-vessel Food Waste Compost Oven Temperature: 60C for 3 days, 50C for 21 days

% Moisture: > 50%


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Mariposa after 42 days Pictures




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Mariposa after 42 days Pictures



Kraft paper


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NorCal Vacaville Windrow Compost

In-vessel Compost pile

Compost temperature: 140 +/- 5F Moisture: 40-45%

Samples moved to windrow compost after 42 days for an additional 150 days


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Mariposa In-vessel Food Waste Compost

Results

42 days (In-vessel)



150 days: (Windrow) Identical to Vacaville result No degradation: Oxo-biodegradable and UV degradable plastic

trash bags; LDPE control.

Some bio-degradation: Sugar cane lids and Kraft paper control

though samples were very wet and fell apart when moved.

Full degradation: no visible fragments- PHA bag,

Ecoflex bag, PLA lids, Biobag trash bags.


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Mariposa In-vessel (42 days) plus

Vacaville Windrow Compost (150 days)Pictures

Note: Same results as Vacaville Compost alone

Oxodegradable bagsKraft paper and sugar cane lids


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Laboratory Biodegradation Compost Materials

Kraft paper, Cellulose filter paper and low density polyethylene controls

Oxo-biodegradable: Ecosafe and Eco-friendly plastic trash bags

Compostable biodegradable products, i.e., PLA straws, Biobag trash bags, PHA

bags, Ecoflex bags Biodegradable: Stalk Market sugarcane lids.

Method (Per ASTM D-5338)

Redesigned of laboratory procedure with

Improve the accuracy of CO2 measurement with LabView data acquisitionsystem and computer control.

CO2 scrubber, 50 psi pressure canister to supply moist air.

45-day test interval

Tests Monitored carbon dioxide and oxygen levels for 45-days.

Phytoxicity tests with tomato seeds.

Regulated metals testing for Cd, Pb, and Co.


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Testing Methods Laboratory Environment ASTM 5338 Standards

Sampling process schematic.

Wet airvoid of CO

2

Computer

CO2

or O2

Detector

Biogas

42 Jars at 50C for 45 days

L b Bi d d i C


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Laboratory Biodegradation Compost

Pictures


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45-day Degradation Results

Fail0.0002.19Oxodegradable bag

Fail

0.0001.70Polyethylene negativecontrol

----0.0001.69Blank compost control

Pass0.01360.14Ecoflex bag

Pass

0.01360.47Biobag trash bag

Pass0.01461.12Sugar cane plate

Pass0.01461.22PLA straws

Pass0.01464.03PHA bag

Pass0.01461.91

Kraft paper positivecontrol

Pass0.01671.99Cellulose positive control

ResultsDegradationrate g/day

BiodegradationConversion %

Material


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Plant Growth Results

Pass8.8013.4418.3373.33Oxo-degradablebag

Pass8.6010.3918.3356.67Ecoflex bag

Pass8.8310.131663.33PHA bag

Pass

8.6319.4032.3360Biobag trash bag

Pass8.779.801470Sugar Cane lid

Pass8.5014.002070PLA Container

Pass

8.6317.502570Polyethylenenegative control

Pass8.4017.7826.6766.67Kraft paper control

Pass

8.7015.2718.3383.33Avicell cellulosecontrol

Pass8.809.8222.6743.33Cellulose control

Pass8.5011.3524.3346.67Compost control

ResultsAverage pHAverageGermination

Index

AverageLength, mmafter 10-days

AverageGermination %

Material


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Regulated Metal Testing

Note: Maximum limit of Pb is 30 mg/kg, Cd is 17 mg/kg and

Co is not regulated in the US.

Pass.001 mg/kgPass0.02 mg/kgPHA bag

Pass.001 mg/kgPass0.02 mg/kgEcoflex bagPass.001 mg/kgPass0.02 mg/kgSugar Cane

Pass.001 mg/kgPass0.02 mg/kgPLA straws

Pass.001 mg/kgPass0.02 mg/kgBiobag

Pass.001 mg/kgPass0.02 mg/kgPolyethylene

Pass.001 mg/kgPass0.02 mg/kgKraft Paper

Pass.001 mg/kgPass0.02 mg/kgCellulose

Pass.001 mg/kgPass0.02 mg/kgCompost

ResultAverage CdConcentrationResult

Average LeadConcentrationMaterial


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Anaerobic Digestion at UC Davis Materials

Kraft paper and low density polyethylene controls


Biodegradable: Food waste and biodegradable products, i.e., PLAlids and straws, Biobag trash bags, PHA bags, Ecoflex bags, andStalk Market sugarcane lids.

Methods

Per Dr. Zhangs research from U.C. Davis Place 1 g of sample in 1-L jar with 0.5L of water waste

and food sludge at 50C.

Duplicate test with new samples.

Tests Monitor biogas production over 30 day period.

More research is needed.

Anaerobic Digestion at UC Davis


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Pictures

A bi Di ti t UC D i


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Results: Duplicate trial: 45 days

Conclusions

Digestion occurs and biogas (CO2 and Methane) is generated for first 15 days.

PHA DOES continues to generate biogas and thus digest anaerobically for the next 30days.

PLA, Ecoflex, oxo-degradable, UV-degradable, and Kraft paper DO NOT generatebio as after 15 da s.

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

0 5 10 15 20 25 30 35 40 45

Digestion time (days)

Biogasyield(L)

Bio bag Oxo bag Straws Yellow bag

Clear Eco flex Food waste Cups

PHA

PLA, Ecoflex, Corn starch

Oxo and UV degradable

Food Waste


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Laboratory Marine Testing Materials

Kraft paper and low density polyethylene controls


Biodegradable: Biodegradable products, i.e., PLA straws, Biobag trash bags,PHA bags, Ecoflex bags, and Stalk Market sugarcane lids.

Methods (Based on ASTM D-6692 standards) Place 30 mg of sample in jar with 100 ml of ocean water at 30C.

Ocean water was retrieved in July 2007 from Big Sur beach in California.

Water was held at 5C until testing. Tests

At 30 days weigh samples after 24 hours of drying in air and thenreplace water with fresh 100 ml and place in oven.

At 60 days weigh samples after 24 hours of drying in air and thenadd fresh 40 ml and place in oven.

At 90 days weigh samples after 24 hours of drying in air.


Laboratory Marine Testing


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Laboratory Marine Testing

Pictures

Experimental Set-up Oxo-degradable 90 days

PHA 30 da s PHA 90 da s


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Laboratory Marine Testing Results

30 days in water No degradation: Oxo-biodegradable and UV degradable plastic trash bags;

LDPE control, Kraft paper control; PLA lids; Sugar cane lids; Biobag trashbags; Ecoflex bag, UV degradable soda rings.

Some degradation: PHA bag- 36% disintegration

60 days in water No degradation: Oxo-biodegradable and UV degradable plastic trash bags;

LDPE control, Kraft paper control; PLA lids; Sugar cane lids; Biobag trash

bags; Ecoflex bag, UV degradable soda rings.


90 days: No degradation: Oxo-biodegradable and UV degradable plastic trash bags;

LDPE control, Kraft paper control; PLA lids; Sugar cane lids; Biobag trash

bags; Ecoflex bag, UV degradable soda rings.


La oratory ua ty Tests or


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Contamination of Recycled Plastics Materials

Recycled PET, HDPE, LDPE

Oxo-biodegradable plastic trash bags Biodegradable: PLA straws and Biobag trash bags

Method

Combine LDPE and Biobag bags at 0%, 10% and 20%. Combine HDPE and PLA at 0%, 5%, and10%.

Heated plastic bags under IR heater and then chopped with grinder.

Injection molded samples with dry blend of plastic.



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a o ato y ua ty ests o

Contamination of Recycled Plastics Processing Injection molding tensile bars with 55 ton Arburg.

Blow molding of bottles with Rocheleau R4 machine.

Blown film with 1 Braybender extruder.

Testing Quality

Melt index, density, moisture %

Opacity, dart impact Mechanical properties

Tensile modulus, elongation, and strength, impact

Samples were tested in batches of 5.


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Results Contamination of Recycled Plastics

Quality tests PLA plastics at concentrations of 5 and 10 wt%

Negatively affected melt index, moisture content of LDPE.

Decreased tensile strength and impact strength of LDPE.

Corn-starch based plastic bags at concentrations of10 and 20 wt%

Negatively affected melt index, moisture content ofHDPE.

Decreased tensile strength and impact strength of HDPE.

Oxodegradable plastics at concentrations of 10 and20 wt% Negatively affected melt index, moisture content of LDPE.

Decreased tensile strength and impact strength of LDPE.



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Results Contamination of Recycled Plastics Mechanical tests

-38-17100-9HDPE 10% PLA

-31420-4HDPE 5% PLA

--------HDPE- neat

-3-5-8-9LDPE 20% biobag

-4-1412-1LDPE 10% biobag

-2-14293LDPE 20% oxo

-2-10233LDPE 10%oxo

--------LDPE- neat

% increase% increase% increase% increase

Impactstrength

TensileModulus

UltimateElongation

Tensilestrength

Material

Summary of Biodegradation Results


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Summary of Biodegradation Results

NoNoNo, for most

Yes, for PHA

Anaerobic Digester(with high moisture levels and

low oxygen and temperature

levels)

NoNo

No, for most

Yes, for PHA

Marine

(with high moisture levelsand low oxygen andtemperature levels)

NoNoNo

Landfill(with low moisture, oxygen,and temperature levels)

NoNo

Yes- 100%

biodegradable

in 180 days

Compost(with proper moisture,oxygen, and temperaturelevels)

Meet ASTM D-

6400 standards Polyethylene

Oxodegradable

Plastics

CompostablePlastics

Environment


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Conclusions Compostable materials degrade under commercial

compost environments. PLA container, Sugar cane lids, PHA bag, Ecoflex bag, and

Husky Eco-Guard plastic bag completely degraded incommercial

Green yard waste, In-vessel compost systems, and

Laboratory conditions Oxodegradable and UV-degradable plastics do NOT

biodegrade in any compost environments.

Oxodegradable and UV-degradable plastics mayfragment into smaller pieces compost environments,but may also create more SEVERE environmentalconsequences.


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Conclusions PHA degraded in marine and anaerobic

digestion environments.

Sugar cane degraded in anaerobic digestionenvironment and also in marine environment.

PLA straws, Ecoflex bag, and Biobag did notdisintegrate in marine environment andbiodegraded slowly in anaerobic digestion

environment.


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Conclusions Biodegradable plastics are a contaminant to

recycled plastics.

PLA and Biobag plastics at concentrations of 10and 20 wt% can negatively impact melt index,

moisture content, tensile and impact properties.

Contamination of biodegradable plastics can becontrolled like other contaminants to recycled

plastics.


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Recommendations The research work will help the expanded use of

compostable plastic materials for selectedapplications.

The compostable materials should be certified ascompostable by BPI and included in procurementstandards.

The compostable plastic materials should perform wellin simple applications, e.g., food service ware, lawnand leaf refuse bags that have dry contents, grocerybags, department store bags, and pet bag products.

Acknowledgements


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Acknowledgements

The author would like to thank the following people

and organizations who have helped develop this

research work: California Integrated Waste Management Board

Mr. Edgar Rojas (CIWMB) and Mr. Mike Leaon (CIWMB)

Dr. Cindy Daley (CSU, Chico), Dr. Ken Derucher (CSU,Chico), Dr. Gregory Kallio (CSU, Chico), Dr. Randy Miller(CSU, Chico), and Mr. Peter Natale (CSU, Chico)

Dr. Fengyn Wang (NorCal Waste Systems), Chris Taylor

(NorCal Waste Systems), and Mr. Greg Pryror (JepsonPrairie Organics).

Mr. Steve Engfer (Mariposa County Waste Management).


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