evaluation of degradable plastic packaging

8/14/2019 Evaluation of Degradable Plastic Packaging

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DRAFTFor Discussion Purposes Only. Do not cite or quote.

Contractors Report to the Board

Performance Evaluation ofEnvironmentally DegradablePlastic Packaging and DisposalFood Service Ware - FinalReport_Draft

May 2007

Produced under contract by:

California State UniversityChico Research Foundation


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S T A T E O F C A L I F O R N I A

Arnold SchwarzeneggerGovernor

Linda S. Adams

Secretary for the Environmental Protection Agency

INTEGRATED WASTE MANAGEMENT BOARD

Margo Reid BrownBoard Chair

Jeffrey DanzingerBoard Member

Rosalie MulBoard Member

Gary PetersenBoard Member

Wesley ChesbroBoard Member

(Vacant Position)Board Member

Mark LearyExecutive Director

For additional copies of this publication, contact:

Integrated Waste Management BoardPublic Affairs Office, Publications Clearinghouse (MS6)

1001 I StreetP.O. Box 4025

Sacramento, CA 95812-4025www.ciwmb.ca.gov/Publications/

1-800-CA-WASTE (California only) or (916) 341-6306

Publication #XXX-XX-XXXCopies of this document originally provided by CIWMB were printed on recycled paper

containing 100 percent postconsumer fiber.

Copyright 2006 by the California Integrated Waste Management Board. All rights reserved. Thispublication, or parts thereof, may not be reproduced in any form without permission.

Prepared as part of contract IWM-C2061 (total contract amount: $65,000, includes other services).

The California Integrated Waste Management Board (CIWMB) does not discriminate on the basis ofdisability in access to its programs. CIWMB publications are available in accessible formats upon request

by calling the Public Affairs Office at (916) 341-6300. Persons with hearing impairments can reach theCIWMB through the California Relay Service, 1-800-735-2929.

Join Governor Schwarzenegger to Keep California Rolling. Every Californian can help to reduce

energy and fuel consumption. For a list of simple ways you can reduce demand and cut your energy andfuel costs, Flex Your Power and visit www.fypower.com.

Disclaimer: This report to the Board was produced under contract by California State University

Chico Research Foundation. The statements and conclusions contained in this report are those of

the contractor and not necessarily those of the California Integrated Waste Management Board, its

employees, or the State of California and should not be cited or quoted as official Board policy or

direction.

The State makes no warranty, expressed or implied, and assumes no liability for the information

contained in the succeeding text. Any mention of commercial products or processes shall not be

construed as an endorsement of such products or processes.
http://www.ciwmb.ca.gov/Publications/http://www.fypower.com/http://www.fypower.com/http://www.ciwmb.ca.gov/Publications/


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2

Table of ContentsTable of Contents ........................................................................................................................ 2

List of Tables................................................................................................................................... 3

Acknowledgements ......................................................................................................................... 5

Executive Summary ........................................................................................................................ 6

Introduction ..................................................................................................................................... 8

Background ..................................................................................................................................... 9

Degradable Plastic Products...................................................................................................10

Life Cycle of Biodegradable and Conventional Plastics....15

Case Study: Use of Compostable and Biodegradable Plastics at CSU, Chico.............................. 16

Degradation, Residuals, and Toxicity of Degradable Plastic Packaging Food Service Products . 18

Current Standards for Biodegradable Plastics............................................................................... 20

Experimental Work ....................................................................................................................... 23

Testing Plan................................................................................................................................... 23

Materials...24

Experimental Methods and Procedures25

Laboratory Environment..25

Carbon Dioxide Concentration Results....27

Biodegradation Results....28

Phytotoxicity Testing...34

Heavy Metal Testing....34

Results..35

Marine Testing .............................................................................................................................. 36

Results..37

Anaerobic Digestion...................................................................................................................... 37

Materials...38

Experimental Procedures..38

Result38

Composting Environments............................................................................................................ 41

City of Chico Municipal Compost Facility..41

Materials and Procedures.41

Results..42University Farm In-vessel Compost Facility...42


Results..42

Vacaville In-vessel Food-waste Compost Facility...43


Results..43


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Mariposa County In-vessel MSW Compost Facility...44


Results..45

Contamination Effects of Degradable Plastics on Recycled Plastics ............................................ 45

Experimental45

Results..46

Conclusions ................................................................................................................................... 48

Recommendations ......................................................................................................................... 49

Appendices .................................................................................................................................... 50

Appendix A. Calculations51

Appendix B. Pictures of Samples at the CSU, Chico Experimental Laboratory.53

Appendix C. Pictures of Samples at the CSU, Chico Farm.56

Appendix D. Pictures of Samples at the City of Chico Municipal Compost Facility..57

Appendix E. Pictures of Samples at the Vacaville In-vessel Compost Facility...59

Appendix F. Pictures of Samples at the Mariposa In-vessel Compost Facility...60

Source Reference Notes ................................................................................................................ 61

List of TablesTable 1. Production information for commercially available degradable plastics. ....................... 11

Table 2. Certification information of commercially available degradable plastics....................... 12

Table 3. Commercially Available Biodegradable and Compostable Polymers............................. 14

Table 4. Summary of key indicators from LCA studies[] .............................................................. 16Table 5. Costs for compostable food service items for CSU, Chico Cafeteria ............................. 17

Table 6. Costs for typical plastic food service items for CSU, Chico Cafeteria ........................... 17

Table 7. Heats of combustion, carbon content, and moisture % for compostable samples........... 29

Table 8. Degradation rates for compostable samples. ................................................................... 30

Table 9. Phytotoxicty of Compost Soil. ........................................................................................ 36

Table 10. Characteristics of the substrates and sludge. ................................................................. 39

Table 11. Quality test results for LDPE and HDPE with oxo and bio contamination................... 47

Table 12. Mechanical test results for LDPE and HDPE with oxo and bio contamination............ 47

Table 13. Mechanical test results for LDPE and HDPE with oxo and bio contamination............ 48

List of FiguresFigure 1. Experimental set-up for laboratory environment. .......................................................... 26

Figure 2. CO2 ppm concentration of BioBag trash bag after 21 days. .......................................... 27


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Figure 3. Carbon conversion percentage for compost control alone. ............................................ 30

Figure 4. Carbon conversion percentage for cellulose control. ..................................................... 31

Figure 5. Carbon conversion percentage for Kraft paper control.................................................. 31

Figure 6. Carbon conversion percentage for polyethylene negative control. ................................ 32

Figure 7. Carbon conversion percentage for corn based BioBag trash bag................................... 32

Figure 8. Carbon conversion percentage for corn PLA clamshell container................................. 33

Figure 9. Carbon conversion percentage for sugar cane plate....................................................... 33

Figure 10. Carbon conversion percentage for PLA cup. ............................................................... 34

Figure 12. Cumulative biogas production from the anaerobic digestion....................................... 40

Figure 13. Cumulative biogas production from the anaerobic digestion....................................... 40

Figure 14. Biogas yield at day 43 from anaerobic digestion ......................................................... 41

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AcknowledgementsThis report is a culmination of work from many people who represent many organizations. Theauthor would like to thank the California Integrated Waste Management Board who provided thefunding for the project. Additionally, the author would like to thank the technical advisory board

members for excellent comments and suggestions, as well as, Mr. Edgar Rojas and Mr. MikeLeaon of CIWMB for providing excellent input and technical direction for the project.

The author would like to thank colleagues at CSU, Chico and UC Davis for their expert help inlaboratory testing and experimental development, in particular, Dr. Cindy Daley, Mr. TimDevine, Dr. Randy Miller, and Mr. Don Sonnot. The author would like to thank the followingstudents who provided very thorough research support during the project: Bret Bosma, StevenFoutes, Jonas Greminger, Nhu Huynh, Maisha Kamunde, Joel Klabo, Deepika Nayyar, and KateTaft. The author would like to thank Dr. Hamed El-Mashad and Dr. Ruihong Zhang from U.C.Davis for excellent collaboration on anaerobic digestion.

Lastly, the author would like to thank people and organizations in the waste managamentbusiness for the opportunity to test the degradable materials in commercial composting facilities,

in particular, Dr. Fengyn Wang (NorCal Waste Systems), Chris Taylor (NorCal Waste Systems),Mr. Greg Pryror (Jepson Prairie Organics), Mr. Steve Engfer (Mariposa County WasteManagement), and Mr. Dale Wangberg (Waste Management Company, Chico Compost Facility.

Produced under a CIWMB contract with CSU, Chico Research Foundation. Contacts are Mr.Edgar Rojas (CIWMB. 916-341-6518) and Dr. Joseph Greene (CSU, Chico. 530-898-4977).

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Executive SummaryThe research in this report details the results of biodegradation testing of several biodegradableand oxodegradable plastics that are commercially available in California. The objectives of theresearch are to evaluate performance, degradation rates and environmental impacts of various

commercially available degradable plastic packaging and disposable food service ware productsin commercially operated compost facilities and in simulated marine environments. The researchwork includes biodegradation testing in five composting environments, a marine environment,and an anaerobic digestion environment. Additionally, the effects of contamination of therecycled plastics with degradable plastics are evaluated.

The first compost environment is a laboratory setting that follows the testing procedures outlinedin ASTM D6400 standard. Samples of five compostable plastic products, along withoxodegradable, UV-degradable plastics, and positive controls of cellulose paper and Kraft paperand one negative control of polyethylene plastic wrap, were placed in a controlled warm and

humid environments of 58C for 45-days. The degradation was evaluated by measuring CO2 gas,which evolves from the degrading compostable samples while in 3.8-Liter jars. The sampleswere tested in triplicate for each material. The testing will be completed by May 15, 2007.

The compost soil samples passed the regulated metals regulations for the U.S. The compost soilat the end of the 45-day biodegradation test from PLA, sugar cane, and starched-based biobag,had lead concentrations of 0.02 mg/kg, which is well below the maximum limit of 30 mg/kg forCalifornia. The cadmium concentrations were also well below the maximum limit of 17 mg/kg.In fact, the amounts of lead and cadmium were less that 1% of the maximum allowable levels.Further testing of the remaining degradable plastics will be completed on approximately May 15,2007.

All of the degradable plastics and controls met the phytotoxicity requirements (poisonous toplants). PHA and sugar cane exhibited biodegradation at the end of 30 days. The Kraft paper,cellulose paper, PLA lid, corn-starch based trash bag, Ecoflex bag, LDPE bag, UV-degradable

and oxodegradable supported growth of tomato seedlings after 10-days.The second compost environment is a commercial compost facility at the city of Chicomunicipal site that is produced from green-yard waste. The compost facility utilizes traditionalwindrow technology. The degradable samples were placed in a fresh compost row and mixedwith green yard waste. The fragmentation of the samples was recorded at 30-day intervals until120 days. The Ecoflex bag, PLA straws, PLA cups, PLA lids, PHA bag, sugar cane plate, andKraft paper degraded fully after 120 days. The corn-starch based trash bag and PLA containersdegraded over 95% in 120 days. Small pieces of these materials were observed. Theoxodegradable and UV -degradable plastics did not degrade or break down into smaller pieces.The oxodegradable plastics did not biodegrade. The degradation and disintegration results at themunicipal compost facility demonstrate that the compostable plastics biodegrade andoxodegradable plastics do not biodegrade under moist green-waste compost.

The third compost environment is a commercial compost production facility at the universityfarm that is made from a mixture of cow manure and straw. The compost facility utilizes in-vessel compost system for 30 days and then traditional windrow system for 90 additional days.As with the green yard waste compost facility, the degradable samples were placed in a freshcompost row and mixed with manure and straw. The fragmentation of the samples was recordedat 30-day intervals until 120 days. The Ecoflex bag, PLA straws, PLA cups, PLA lids, PHA bag,sugar cane plate, and Kraft paper degraded fully after 120 days. Similar to the results at thegreen-yard waste compost facility, small pieces of corn-starch based trash bag and PLA

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containers were in 120 days. The oxodegradable and UV-degradable plastics were not placed inthe manure compost due to contamination concerns. The degradation and disintegration resultsat the municipal compost facility demonstrate that the compostable plastics biodegrade andunder moist manure waste compost with in-vessel technologies.

The fourth compost environment is a commercial food-waste compost production facility in

Vacaville, CA. The facility composts the food waste from San Francisco. The compost facilityutilizes in-vessel compost system for 30 days and then traditional windrow system for 90additional days. The samples were placed in burlap sacks and mixed with solid waste. Thefragmentation of the samples was recorded at 30-day intervals until 180 days. The corn-starchbased trash bag, PLA lids, Ecoflex bag and PHA bag degraded fully. The sugar cane lidsdegraded at similar rates as the Kraft paper control. The oxodegradable and UV -degradableplastics did not degrade or break down into smaller pieces.

The fifth compost environment is a commercial municipal solid waste (MSW) waste compostproduction facility in Mariposa, CA. The facility composts the MSW waste from Mariposacounty, including Yosemite National Park. The compost facility utilizes in-vessel compostsystem for 20 to 50 days and then uses the screened compost as landfill cover. The samples wereplaced in burlap sacks and mixed with solid waste. After 45 days, the biodegradable plastics

demonstrated biodegradation with fragments of Kraft paper, sugar cane lids, PLA lids, cornstarch bag, PHA bag, and Ecoflex bag. The samples were removed from the in-vessel compostand placed in a static pile in Vacaville for 120 days. The fragmentation of the samples wasrecorded at 30-day intervals until 165 days. The degradation results were identical to the onesfrom the Vacacille testing. The corn-starch based trash bag, PLA lids, Ecoflex bag and PHA bagdegraded fully. The sugar cane lids and Kraft paper were significantly degraded. Several piecesof each were observed. The sugar cane lids had similar biodegradation rate the Kraft papercontrol. The oxodegradable and UV-degradable plastics had some holes in the bags and hadsome discoloration, but did not fragment into smaller pieces.

The sixth biodegradation environment was in and anaerobic digestion vessel. The samples wereplaced in 1-litter jars with food waste and digested in an anaerobic (without oxygen)

environment at 50C at the U.C. Davis research facility. Only PHA and sugar cane exhibitedbiodegradation at the end of 30 days. The corn-starch based trash bag, PLA cup, Ecoflex bag,and Kraft paper did not generate any biogas and thus did not biodegrade. Likewise, the UVdegradable and oxodegradable plastics did not biodegrade.

The last biodegradation testing was in marine environment. The samples were placed in a 500-

ml jar and kept at 30C for 60 days. Only PHA experienced biodegradation at 30-day and 60-dayintervals. Similar to the anaerobic digestion experiments, the corn-starch based trash bag, PLAcup, Ecoflex bag, and Kraft paper did not have mass reduction due to biodegradation. The sugarcane lids, also, did not exhibit biodegradation. Likewise, the UV degradable and oxodegradableplastics did not biodegrade.

The effects of degradable plastics on recycled plastics were evaluated by measuring the

moisture, melt index, impact, and tensile properties of plastic samples with several amount ofcontamination from PLA, starch based plastics, and oxodegradable plastics. The moisturecontent was very low in all of the contaminated plastic materials and slightly higher than HDPEand LDPE alone. Specific gravity was measured with an electronic densimeter, model MD-300S,from Qualitest Incorporated. The oxodegradable plastic and Biobag biodegradable plasticsincreased the density of the recycled LDPE plastic by 2.2% and 5.2% respectively for 20%addition of the contaminant. Also, PLA increased the density of recycle HDPE plastic by 1.4%with the addition of 5% contaminant and by 5.3% with the addition of 10% contaminant.

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The melt index of the samples were measured with a LMI 4002 series melt flow indexer fromQualitest Incorporated. The melt index was significantly changed with the addition ofoxodegradable plastics to LDPE, cornstarch-based biodegadable plastics to LDPE, and PLAadded to HDPE.

The results indicate that melt index is significantly affected with the addition of contaminants of

oxo-degradable and biodegradable plastics. Density is moderately affected by the contaminantsand moisture content is minimally affected by the presence of degradable contaminants. Thecontamination effects on film properties will be evaluated for haze, opacity, and dart impact.

The tensile results indicate that oxodegradable plastic reduced the tensile modulus between 10and 15% and increased the elongation at break between 23 and 28% than from LDPE alone.PLA contamination of 10% had a negative effect on HDPE with a reduction of 9% in tensilestrength, a reduction of 38% in modulus and an increase in elongation of 100%. Similarly,cornstarch plastic had a similar negative effect on LDPE with a 9% reduction of tensile strength,a 8% reduction in modulus, and 8% reduction in elongation for the sample with 20% cornstarchplastic contamination.

The impact results indicate that oxodegradable plastic reduced the tensile modulus between 10

and 15% and increased the elongation at break between 23 and 28% than from LDPE alone.PLA contamination of 10% had a negative effect on HDPE with a reduction of 9% in tensilestrength, a reduction of 38% in modulus and an increase in elongation of 100%. Similarly,cornstarch plastic had a similar negative effect on LDPE with a 9% reduction of tensile strength,a 8% reduction in modulus, and 8% reduction in elongation for the sample with 20% cornstarchplastic contamination. Additional testing in the future can provide better understanding of theeffects of contamination on the recycled plastics.

The research work can help increase the use of compostable plastic materials for selectedapplications. The compostable materials should be certified as compostable by BPI and includedin procurement standards. The compostable plastic materials should perform well in simpleapplications, e.g., food service ware, lawn and leaf refuse bags that have dry contents, grocerybags, department store bags, and pet bag products. The compostable plastics would not mostlikely perform well in trash bag uses due to the likely exposure to moist debris. Thus, trash baguse is not recommended at this time. Compostable plastic materials could be very economical fororganizations and institutions that service a controlled population, e.g., hospitals, correctionalfacilities, schools, and cruise ships.

IntroductionThe California Integrated Waste Management Board (CIWMB) initiated a research program toevaluate performance, degradation rates and environmental impacts of degradable plasticpackaging and food service-ware products in commercially operated compost facilities and insimulated marine environments. The term degradable encompasses products that are marketed

as biodegradable, compostable, photodegradable, oxo-degradable, or degradable through otherphysical or chemical processes.

The Department of Mechanical Engineering Mechatronic Engineering and ManufacturingTechnology at California State University, Chico performed the research in the polymertechnology laboratory. The objectives in the research project are to evaluate the effectiveness ofcommercially available degradable plastic products on the basis of intended use, degradability,toxicity, and cost. Additionally, the research project will generate environmental safetyassessments, assess the impact of degradable plastics on the plastics recycling stream, and

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identify future research needs. The project is broken down into four areas, including, a detailedwork plan and budget, literature review, testing for performance evaluation in full-scalecomposting and anaerobic digestion, and evaluation report.

This research is a continuation of a previous research study that presented results ofbiodegradation testing of several compostable plastics that are commercially available in

California. The research found that the compostable materials degrade under laboratorycompostable conditions as specified in ASTM D6400. The past research project represents aninitial study of several common compostable plastic materials. The research did not addressother degradable products nor accelerated in-vessel composting methods. Additional researchwork is needed to evaluate other degradable plastics, including oxo-degradable materials, incommercial compost operations that utilize aerobic in-vessel composting. Also, degradability inmarine environments and life cycle assessments of the degradable plastics should beinvestigated. Lastly, the current research will evaluate the effects of contamination of thedegradable plastics on recycled plastics.

Background

Plastics can be produced from natural or synthetic materials. Traditional plastics, with an annualworld production of approximately 140 million tones,1 are typically made from petroleum basedproducts. Alternatively, biobased polymers are produced from natural materials, e.g., starch fromcorn, potato, tapioca, rice, wheat, etc., oils from palm seed, linseed, soy bean, etc., orfermentation products, like PLA, PHA, and PHB. Most biobased materials are biodegradable,though some are not biodegradable. For example, polyesters can be made from soybean oil,though they are not biodegradable since the polymer is not consumed by microorganisms.Polyurethane can be made by reacting organic alcohol with isocyanate, but it is notbiodegradable since it is not consumed by microorganisms, either. Some petroleum-based areconsidered biodegradable polymers since they are consumed by microbes in the soil andbiodegrade in compost environments. Aliphatic-aromatic co-polyester polymers from BASF and

-caprolactam are made from petroleum materials and are consumed by microorganisms. Most

petroleum based polymers, though, are not biodegradable. Additionally, polymers that havestarch or degradable additives as a component are not biodegradable since only a portion of thepolymer is consumed by microbes in the soil. Prodegradant additives are combined withpolyethylene to produce an oxodegradable synthetic polymer that causes the plastic todisintegrate into small fragments when exposed to oxygen. Similarly, photodegradable plasticshave additives that cause the plastic to disintegrate in sunlight into small fragments. The smallpieces of plastic, though, are not consumed by microorganisms and may cause considerableenvironmental harm to animals if ingested. Biodegradability is defined as a process where allmaterial fragments are consumed by microorganisms as a food and energy source.Biodegradable polymers can not have any residuals or by-products remaining. The time periodrequired for biodegradation is dependent upon the disposal system environment, which can belandfill soil, aerobic compost, anaerobic digestion, and marine. Many types of biodegradable

polymers are available to degrade in a variety of environments, including, landfill, sunlight,marine, or compost. The three essential components of biodegradability is that the material isused as a food or energy source for microbes, that a certain time period is necessary for thecomplete biodegradation, and that the material is completely consumed in the environment.

Biodegradable plastics can degrade in composting facilities and break down into water, methane,carbon dioxide and biomass. Micro-organisms in the soil or compost degrade the polymer inways that can be measured by standard tests over specified time-frames. Compostable plasticsare defined according to the ASTM D6400 standard as materials that undergoes degradation by

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biological processes during composting to yield carbon dioxide, water, inorganic compounds,and biomass at a rate consistent with other known compostable materials and leave no visibledistinguishable or toxic residue. Biodegradable plastic is defined according to the ASTM D6400standard asa degradable plastic in which the degradation results from the action of naturallyoccurring microorganisms such as bacteria, fungi, and algae.

If a degradable plastic does not meet these requirements, then it cannot be labeled asCompostable in California. [ ]2 The compostable plastics can then be collected along with othernon-plastic compostable materials and sent to composting facilities rather than landfills.Unfortunately, not all products marked as biodegradable are also compostable. This compostablerequirement can lead to confusing labelling of products and misunderstading of acceptablebiodegradability. Two independent organizations, the US Composting Council (USCC) and TheBiodegradable Products Institute (BPI), jointly established procedures to verify thecompostabliity claims of biodegradable products and created a Compostability Logo to verifythe compliance with ASTM D6400 compostability standards. [ ]3

BPI in conjunction with the USCC performs product evaluations on every product that isawarded the Compostable Logo. BPI provides important criteria for valid full-scale testing ofcompostable plastics.[ ]4 The BPI Logo Program is designed to certify and identify plastic

products that will biodegrade and compost satisfactorily in actively managed compost facilities.

BPI provides a list of approved products with a compostable logo that can help consumers selectproducts will degrade quickly in a compost environment and not leave any residue that could beharmful to plant growth. The products include compostable bags and film, food service items,and resins.

Degradable Plastic ProductsMany communities are interested in using biodegradable products to reduce the pollution causedby lightweight plastic bags. San Francisco recently is requiring the use of compostable orrecyclable bags in supermarkets, drugstores, and other large retailers.[ ]5 Similarly, the city of

Hutchinson, MN, compost facility will only collect green waste with biodegradable plasticbags.[ ]6 The biodegradable bags are delivered to those who participate in the curbside organicsprogram every four months. All types of organic materials can be placed in the biodegradablebags, especially if the material is smelly, drippy and might blow around in the wind. TheEcoGuard compost bag the City of Hutchinson distributes to residents converts into carbondioxide and water within a few weeks after disposal. Larger 55 gallon biodegradable bags areavailable for $1.00/bag.

Table 1 lists the product applications, supplier information and production capacity of severalcommercially available degradable plastics. The plastic products include biodegradable,compostable, oxodegradble, UV-degradable polymers.

Table 2 lists polymer type, degradation extent and rate, shelf life, and certification of several

degradable plastics. The degradable polymers can degrade aerobically in compost, landfill, andmarine environments. The rate of decomposition depends upon the temperature, moisturecontent, and population of microorganisms in the particular environment.

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Table 1. Production information for commercially available degradable plastics

Trade Name Product Application Supplier-location

ProductionCapacity

Costper unit

Biomax Plates, bowls, containers Dupont/Metabolix Inc

TBD

BiopolPHA

Film, sheet, cups, trays,containers.

Metabolix Inc-USA

100 millionpounds peryear

[ ]7

EASTAR Bio Bags, films, liners, fiber andnonwovens applications,

Novamont NA-Italy

33 millionpounds peryear[ ]8

Ecovioplastic PLA-Ecoflex Bags, sheets, film BASF- USA TBD

Cereplastresins

Nat-UR cold drink cups,foodservice containers andcutlery

CereplastCorporation-Hawthorne CA


[ ]9

EcoFlex Bags, liners, film BASF-Denmark


NatureWorksPLA

Cold drink cups, foodservicecontainers and cutlery

Nature WorksLLC, Cargil-Dow- USA


Stalk MarketSugar Cane

Foodservice containers andcutlery

AseanCorporation,China


Mater-Bi

Resins

Bags, liners, and film products Novamont

Corporation-Italy

40 million

pounds peryear[ ]12

EPIadditives forLDPE andHDPE

Bags, sheets, film, trays.

Additive is available for manyplastic products.

Biocorp, Inc.

Becker, MN,USA


Oxo- andUV-degradableadditives forLDPE andHDPE

Bags, sheets, film, trays.

Additive is available for manyplastic products.

EPIEnvironmentalTechnologies,Inc.

Nevada, USA


Polystarchmaster batchfor LDPE,HDPE, andPP

Bags, sheets, film, trays.Containers.

Starch additive is available formany plastic products.

Willow RidgePlastics, Inc.

Erlanger, KY,USA


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Table 2. Certification information of commercially available degradable plastics.

Trade Name Polymer Source/Type Rate and Extent ofDegradation(Environment)

Shelf Life BPICertified

ISOCertified

Biomax

Mixed aliphatic and

aromatic polyester

Compostable in 6

months (compost)

12 to 18

months

Yes Yes

BiopolPHA

poly-hydroxyalkanatevia bacteria

Compostable in 6months (compost)

12 to 18months

No No

EASTARBio

Modified PETpolyester


12 to 18months

Yes Yes

Ecovio plasticPLA-Ecoflex TBD TBD

No No

Cereplastresins

Plant organic sources Compostable in 6months (compost)

12 to 18months

Yes Yes

EcoFlex Mixed aliphatic andaromatic polyester


12 to 18months

Yes Yes

NatureWorksPLA

polyester Compostable in 6months (compost)

12 to 18months

Yes Yes

Stalk MarketSugar Cane

Sugar cane Biodegradable(compost)

12 to 18months

No No

Mater-Bi

Resins

Corn starch Compostable in 6

months (compost)

12 to 18

months

Yes Yes

EPI additivesfor LDPEand HDPE

Oxodegradableadditive for HDPEand LDPE

Disintegrates butnot compostable

2 to 3 years No No

Polystarchmaster batch

Starch and LDPE orHDPE, and PP

Disintegrates butnot compostable

2 to 3 years No No

The majority of compostable plastics belong to the polyester family, including poly-lactic acid(PLA), which is manufactured and supplied by Cargill Dow. PLA is produced from thepolymerization of lactic acid. It is also referred to as poly lactide. PLA is a very commonbiodegradable polymer that has high clarity for packaging applications. It can be used forthermoformed cups and containers, forks, spoons, knives, candy wraps, coatings for paper cups,optically enhanced films, and shrink labels. PLA plastics are the most common biodegradableplastic to customers around the world. PLA has applications in the United Sates, Europe, Japan,Australia, and other countries. In 1999, Dow Chemical and Cargill created a joint venture,named, Cargill-Dow to become the largest biodegradadable polylactic acid producer in the world

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with annual capacity of 140,000 tonnes per year. [ ]13 In 2005, Dow and Cargill ended thepartnership by purchasing all of Dow Cargill LLC interests from Dow Chemical.

Polylactic acid (PLA) is a renewable aliphatic polyester that has a potential for use incompostable and biodegradable plastic bags. The biopolymer PLA bags from Cargill Dow arebeing used in Taiwan for commercial packaging products. The bags are referred to as Nature

Green. PLA is a bio-based plastic made from corn. Cargill Dow claims that the materialperforms as well as traditional plastics and fits all current disposal systems, including inindustrial compost facilities. [ ]14 NEC Corporation in Tokyo reports that natural-fiberreinforcements derived from the Kenaf plant can increase PLAs rigidity and heat resistance by70% to 80%. NEC reports that PLA reinforced with 20% (by weight) Kenaf fibers has a heat-

distortion temperature of 248F and is expected to find commercial use in computer housings. [ ]15

Lactic acid is a material that is obtained from the fermentation of agriculture and food by-products containing carbohydrates and was first discovered in 1955.[ ]16 PLA is producedcommercially in large-scale bioreactors. Microorganisms convert sugar feedstock to lactic acidvia fermentation. PLA is polymerized from isolated lactic acid by conventional means to low-molecular weight polymer. The polymer is subsequently polymerized to produce a cyclicdimmer form (lactide) which is made into a high molecular weight polymer using metalcatalysts. [ ]17 The chemical structure of PLA is [C3H4O2]n.

Fermentation is also used in the production of polyhydroxyalkanoates (PHA), which is a familyof polyesters produced naturally by microorganisms. Sugar feedstocks are fermented bymicroorganisms to produce PHA. Other polyesters produced with the similar process are PHBand PHBV. [ ]18 PHA is biodegradable polymer that can produce bags, film, sheet, and injectionmolded products.

Eastman Chemical opened an Eastar Bio plant in the U.K. in 2002 with a production capacity of33 million pounds per year. [ ]19 Eastar Bio copolyester is available currently in two formulas.Eastar Bio GP copolyester is best suited for extrusion coating and cast film applications. EastarBio Ultra copolyester is designed for use in blown films. Both materials are also being used in

fiber and nonwovens applications. Eastar Bio copolymester is produced from butanediol, adipicacid, and terephthalic acid. [ ]20 Other biodegradable copolyesters are Ecoflex manufactured byBASF and Biomax manufactured by Dupont. Ecoflex is known for its blown film applicationssuch as packaging films, agricultural films, hygienic films, and trash bags. It has similarproperties to a commodity polymer, LDPE. Ecoflex provides a compostable plastic material to

produce trash bags. Poly -caprolactone (PCL) is a synthetic polyester that is also biodegradabledue to the presence of oxygen in the polymer backbone, which makes the polymer susceptible tohydrolysis. [ ]21

Many biodegradable polymers are produced from natural renewable resources. Natural polymersare biodegradable since microorganism consume them as a food source. The most commonnatural polymers are made from starch. Starch-based polymers can be produced from potato,corn, wheat, or tapioca. The annual world production of starch is greater than 32 million tonnes.

[ ]22 The U.S. annual production is 16 million tonnes. The major polymer components of starchare amylase and amylopectin. The ratio of amylase to amylopectin varies with source plants,which affects physical properties. Biodegradable polymer typicallyincludes additives to improvethe properties and to enable it to be converted from powder to plastic sheet, film, or injectionmolded parts. The polymer is produced in an extruder or injection molder at much lowertemperatures than typical plastics. Biodegradable cups and containers are manufactured bysubsequently thermoforming the extruded plastic sheet into the desired container products. For

example, Mater-Bi[ ]23 is made from corn starch, PCL, and additives, such as, vinyl alcohol,

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ammonium hydroxide, and other proprietary components. Mater-Bi biodegradable bags contain arenewable component and a non-renewable petroleum component.

Table 3. Commercially Available Biodegradable and Compostable Polymers*

Material Type Supplier/

Distributor

Products Degradation

Products

Extent of

Degradation

Standar

MetBiomax aliphatic

copoly-esters,modifiedPET

Dupont/www.allcompost.com

Coating and filmfor foodpackaging,sandwich bags,utensils, fibers.

Carbondioxide,water,biomass.

2 to 4months incompostdependingupontemperature

ASTMD6400

Biopol PHB/Vpolybuty-rate andvaleric acid

Metabolix Inc/Biocorp

Consumerdisposables,Containers,trash bags,packaging

Carbondioxide,water.

20 days insludge, to 1month incompost

ASTMD6400,EN1343

EastarBio Biodegrad-ablecopolyester

Eastman ChemicalCompany/ FarnellPackagingBiodegradableProducts

Trash bags,film, liners Carbondioxide,water,biomass.


ASTMD6400,EN1343

Ecoflex Aliphatic-aromaticPolyester

BASF/www.allcompost.com

Compost bags,trash bags,carrier bags,fruit andvegetable bags.



ASTMD6400,EN1343

Mater-Bi

60% starchand 40%polyvinylalcohol

Novamont/ BioBagCorporation

Trash bags,lawn andgarden bags



ASTMD6400,EN1343BPI

Nature-Works

Polylacticacid (PLA)

Cargill Dow/BiodegradableFood Service, Eco-Products, Inc.

Clear cups,clamshells,salad bowls

Carbondioxide,water


ASTMD6400,EN1343

*Note: The polymers are available in bag, Gaylord, or truckload quantities.

The compostable plastics biodegrade completely in the proper composting environment and donot leave any residue. The biodegradable plastics that are certified by BPI are fullybiodegradable in compost environments. The bacteria in soil and compost will consume theorganic components of the biodegradable plastics.

Some degradable products are made from synthetic polymers that have additives, which causesdisintegration in outside environments over time. EPI Environmental Technologies Incorporated

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provide TDPA (Totally Degradable Plastic Additive) for polyethylene and polypropylenemanufacturers to produce plastic bags, films, and products that degrade over time. [ ]24 The non-starch based additive uses ultraviolet light and oxidation to break the polymer chains resulting ina reduction ofmolecular weight of the plastic. The additive is for use in food contactapplications. [ ]25 TDPA additive technology has been used with plastic products in NorthAmerica, Europe, Asia, Australia, and New Zealand. The oxodegradble plastics can leave small

plastic fragments as residue after oxidation.

The residue and fragments from the oxodegadable plastics can result in similar experiences aswhen starch is added to polyethylene. Starch-based polyethylene plastics are available at WillowRidge Plastics Incorporated. The starch master-batch products have been developed for use inblown film, injection molding and other applications with polyethylene, polypropylene, andpolystyrene plastics. [ ]26 Starch was added to conventional plastics to cause disintegration overtime. Microorganisms in the soil digest the starch that causes the plastic to break down intosmaller pieces. In 1989, Mobile Company produced Hefty bags from polyethylene with acornstarch additive. The bags broke down when exposed to sunlight into smaller plastic particlesbut did not degrade in landfills. [ ]27 The starch-polyethylene bags are not BPI certified and cancause serious environmental consequences as fragments of polyethylene will be left in the soil

after the starch biodegrades.

Life Cycle of Biodegradable andConventional PlasticsEnvironmental Life Cycle Assessment (LCA) is a method developed to evaluate the overallenvironmental costs of using a particular material. LCA includes mass balance of inputs andoutputs of systems and to organize and convert those inputs and outputs into environmentalthemes or categories relative to resource use, human health and ecological areas. [ ]28 LCA

consists of four independent elements, namely, definition ofgoal and scope, life cycle inventoryanalysis, life cycle assessment, and life cycle interpretation. [ ]29

The goal and scope defines the item that is analyzes. The goal and scope involve the use ofbiodegradable plastics as compared to conventional polyethylene plastics. LCA can be used forother materials and can be compared to other plastics or even metals. Life Cycle Inventory (LCI)is the quantification of inputs and outputs of a system, including, all emissions on a volume ormass basis (e.g., kg of CO2, Kg of cadmium, cubic meter of solid waste). Life Cycle ImpactAssessment (LCIA) converts these flows into simpler indicators. LCA reports emissions will bereported on a basis of 1 kg plastic. Health and safety exposure and hazard assessments are notpart of LCA. The life cycle impact assessment evaluates the significant of potentialenvironmental impacts using the results of the life cycle inventory analysis. The range goes fromthe making of the raw materials, which can take place in different parts of the world, to the

making of the detergent product, which takes place in a few, well identified, locations. Usageand disposal are critical data to collect in order to analyze and understand the life cycle impact ofa "product." Life cycle interpretation makes conclusions from both the life cycle inventoryanalysis and the life cycle impact assessment.

The life cycle analyses of PLA, Materi-bi, PHA, and other biodegradable plastics are comparedfrom thirteen publications. [ ]30 The report summarizes the LCA of several biodegradablepolymers and conventional plastics as indicated in Table 6. The results assume a functional unitof 1kg of plastic.

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Table 4. Summary of key indicators from LCA studies[31]

Type ofplastic

Cradle to gravenon-renewableenergy use (MJper Kg)

Type of wastetreatment

Green House Gasemissions (kgCO2 per kg)

LDPE 80.6 Incineration 5.04

PET (bottle) 77 Incineration 4.93

Polycaprolactone(PCL)

83 Incineration 3.1

Mater-Bi

starch film grade

53.5 Incineration 1.21

PLA 57 Incineration 3.84

PHA 81 Incineration Not available

The results are subject to many uncertainties in the actual use of the polymeric materials. Theresearch studies used different functional units. Incineration is a common way in Europe todispose of the materials. Composting is more common in the U.S. and would require much lessenergy use of the materials and a more sustainable alternative. Very little LCA research isavailable for compost solutions. The number of LCA for biodegradable polymers is limited. Nocomprehensive LCA have been published for PLA (plant based), cellulose polymers (plantbased), or for biobased biodegradable polymers, such as, Ecoflex.

The life cycle analysis shows that bags made of Mater-Bi clearly have a better environmentalimpact than paper bags, and are comparable with bags made of polyethylene incinerated aloneafter separation from the waste. [ ]32 NatureWorks

TM

polylactide (PLA)is a versatile polymer

produced by Cargill Dow LLC. [ ]33 NatureWorks polymer requires fewer fossil resources andemits significantly less greenhouse gases than most of the traditional plastics. Cradle-to-factorygate production process of NatureWorks Polymer currently uses 62-68% per cent less fossilfuel resources than the traditional plastic materials such as PET, PS, PP, HDPE, and LDPE. [ ]34

Case Study: Use of Compostable and Biodegradable Plastics atCSU, Chico

The true costs of compostable plastics can be offset by the cost of disposal. California's annualcosts for cleaning up and diverting plastic waste to landfills is conservatively estimated at morethan $750 million annually. [ ]35 Plastic represents 50 to 80 percent of the volume of littercollected from roads, parks and beaches, and 90 percent of floating litter in the marineenvironment. In 2005, California Transportation Department spent $16 million cleaning up litteron California highways. [ ]36

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The costs of disposal at CSU, Chico were studied in the research project. For a 1-week duration,compostable plastic products replaced the plastic products on campus. The compostable productsfrom the university cafeteria were collected and sorted to remove non-compostable items andthen sent to the university farm for composting. The disposal costs were be monitored andcompared to typical weekly costs.

Several companies provide compostable RPPCs, cutlery, and bags.[ ]37

The biodegradableplastics are sold through retailers and distributers. Three of them are Eco-Products of Colorado,Biodegradable Food Service of Oregon, and NAT-UR Store of California. The products aretypically food services items, e.g., cups, plates, utensils, and bags, trash, storage, pet products,lawn and leaf. Eco-Products provided a quote for 1-weeks worth of products for use at the CSU,Chico cafeteria. Table 6 lists the costs for the compostable products. Alternatively, the costs ofconventional plastic items are available from www.foodservicedirect.com and are listed below.

Table 5. Costs for compostable food service items for CSU, Chico Cafeteria

Product Volume, weekly Price per Cost

1 Plate: 9" Plate. Unbleached BioCane 5,000 $0.11 $525

2 Oval plate: 10". Unbleached BioCane 5,000 $0.10 $504

3 Plate: 3 item plate. Unbleached BioCane 5,000 $0.11 $574

4 Cup: 16 oz PLA 10,000 $0.09 $915

5 Cup: 24 oz PLA 10,000 $0.07 $710

6 Salad container- 6" x 6" with lid. PLA 5,000 $0.14 $690

7 To go Container: PLA 5,000 $0.22 $1,114

8 Fork: PLA 5,000 $0.04 $196

9 Lid: PLA 10,000 $0.04 $426

10 Straw: PLA 10,000 $0.01 $98

11 Trash bag: 55 gallon. Corn starch 500 $1.00 $50012 Office trash bag: 10 Gallon. Corn starch 100 $0.12 $12

Total $6,263

Table 6. Costs for typical plastic food service items for CSU, Chico Cafeteria

ProductVolume,weekly Price per Cost

1 Plate: 9" Plate. Unbleached BioCane 5,000 $0.03 $166

2 Oval plate: 10". Unbleached BioCane 5,000 $0.14 $677

3 Plate: 3 item plate. Unbleached BioCane 5,000 $0.15 $737

4 Cup: 16 oz PLA 10,000 $0.06 $5845 Cup: 24 oz PLA 10,000 $0.06 $584

6 Salad container- 6" x 6" with lid. PLA 5,000 $0.12 $611

7 To go Container: PLA 5,000 $0.09 $450

8 Fork: PLA 5,000 $0.03 $141

9 Lid: PLA 10,000 $0.04 $384

10 Straw:PLA 10,000 $0.01 $ 80

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11 Trash bag: 55 gallon. Corn starch 500 $0.42 $209

12 Office trash bag: 10 Gallon. Corn starch 100 $0.09 $ 9

Total $4,631

The cost penalty for using compostable products is the difference between the two costs, or$1,632 per week. The extra costs can be offset by the reduced costs for disposal since the wasteproducts will be composted in an aerobic in-vessel compost at the university farm and not sent tolandfill.

Degradation, Residuals, and Toxicity ofDegradable Plastic Packaging Food

Service ProductsThere is nothing about the characterization of constituents and the presence of hazardousmaterials in the degradation of plastic packaging and food service ware products. Thecharacterization usually identifies the composition of materials (e.g. urea, ethylene glycol,glycerine, etc). In the scope of work we asked for the identification and quantification ofdegradation byproducts and the fate and effect on the specific environments]

Degradable products include three types of materials that degrade over time; one that degradesafter exposure to sunlight, oxygen, or other degradation mechanism; one that biodegrades whenexposed to microorganisms; and a third that completely biodegrades within 6 months whenexposed to compost environment. Degradable plastics can break down into smaller particles ifblended with an additive to facilitate degradation. However, the oxo-degradable plastic bags in

compost environments can take several years to biodegrade depending on the amount of sunlightand oxygen exposure.[ ]38 Polyethylene plastic bags that are produced with starch additives alsodegrade over time as microorganism digests the starch. The breakdown of degradable plasticshas been categorized into disintegration and mineralization. [ ]39 Disintegration occurs when theplastic materials disintegrate and are no longer visible, but the polymer still maintains a finitechain length. Mineralization occurs when the polymer chains are metabolized by microorganisms after the initial oxidation process to carbon dioxide, water, and biomass.

Oxo-degradable polymers break down into small fragments over time but are not consideredbiodegradable since they do not meet the degradation rate or the residual-free content specifiedin the ASTM D6400 standards. The plastics do disintegrate but leave small plastic fragments inthe compost, which violates the ASTM D6400 standards. The ASTM D6400 standarddifferentiates between biodegradable and degradable plastics.

Biodegradable polymers are those that are capable of undergoing decomposition into carbondioxide, methane, water, inorganic compounds or biomass by the actions of microorganisms.Biodegradable polymers break down, but the degradation rate is not specified. Somebiodegradable polymers degrade very quickly, while others can take much longer. Also, the wayin which degradation is measured is not standardized for biodegradable polymers. Somebiodegradable polymers break down more quickly in compost soil than in landfills or in marineenvironments. Thus, many polymers can claim to be biodegradable since there are insufficientstandards to regulate them.

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Compostable polymers are those that are degradable under compositing conditions, whichinclude actions of microorganisms, i.e., bacteria, fungi, and algae, under a mineralization ratethat is compatible with the composting process. Compostable polymers, though, must meet a setof clearly defined standards that define the rate of decomposition, residual levels, and by-products that can be measured in standardized tests. The compostable materials must degrade60% in 45 days in a compost environment per ASTM D-6400. If the biodegradable plastic

degrades in a specified compost environment in 45 days at a rate of at least 60% then it isaccepted as compostable. It also must support plant life and not have any toxic residualsubstances. This is similar to the European standards.Also, compostable polymer products undergo degradation that leads to conversion of thepolymer into carbon dioxide in aerobic conditions, carbon dioxide/methane in anaerobicconditions and water. Degradation can only occur when the polymer is exposed tomicroorganisms found naturally in soil, sewage, river bottoms, and other similar environments.

This research is a continuation of a previous research study that studied biodegradation ofseveral compostable plastics that are commercially available in California. The research foundthat the compostable materials degrade under laboratory compostable conditions as specified inASTM D6400, though the corn-starch based Biobag trash bag did not meet the degradation rate

criterion.

The PLA cup, container, sugar cane plate, and corn starch based trash bag met the phytotoxicityrequirements and supported growth of tomato seedlings after 10-days. Soil samples from thecompostable materials did not leave any toxic residue and had very little detectable heavymetals, 100 times lower than the Lead and Cadmium established limits. The degradation anddisintegration results at the university farm demonstrated that the compostable materials degradein moist manure-based compost. The potato-starch based tray, corn-starch based trash bag, PLAplate, PLA straw, and PLA container degraded at similar rates as the cellulose control. Thedegradation and disintegration results at the municipal compost facility demonstrated that thecompostable materials degrade in moist green-waste compost. The PLA container, PLA cup, andPLA knife degraded at a similar rate as the Avicell cellulose control and were degraded

completely in 7-weeks. The cornstarch-based trash bag and sugar cane plate degraded at asimilar rate as the Kraft paper control. The three materials degraded between 80 and 90% after20 weeks.

The biodegradability of five different biodegradable garbage bags was analyzed according to theDIN-standard. [ ]40 The tests proved that a biodegradable polymer can be degraded undercontrolled composting conditions. The bags were made from cornstarch, polycaprolactaone andKraft paper. The results demonstrated that all five plastic products decomposed to the Europeanstandards of 60% within six months. The bags were considered fully biodegradble since theydegraded and disintegrated by breaking down into carbon dioxide and water, and left no toxicresidue in the soil. The bags are not considered compostable since they were not tested forphytotoxicity.

Mater-Bi is a wholly compostable polymer based on a blend of at least 50% starch with theremaining synthetic hydrophilic degradable polyester. The polymer was evaluated for suitabilityin disposal by composting. [ ], [41 42], [ ]43 The results indicate that Mater-Bi is readily degradable instandard laboratory biodegradation tests, including semi-continuous activated sludge (SCAS) testfor simulating breakdown in municipal waste-water treatment plants and pilot composting

systems. The degradation rate of Mater-Bi bags depends on the exact formulation used and

physical properties of the product. Toxicity tests undertaken with the Mater-Bi bags andcomposted products have shown that they are non-toxic in the standard animal and plant tests.

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The compostable materials must also not leave any toxic residues or chemicals that negativelyaffect the compost soil quality. The quality of the compost can be evaluated for analytical andbiological criteria, including soil density, total dry solids, salt content, inorganic nutrientscontent, and eco-toxicological behavior. [ ]44 The inorganic nutrients evaluated in the compost aretotal nitrogen, phosphorous, magnesium or calcium, and ammonium-nitrogen. The eco-toxicological tests can include determination of growth inhibition with tomato and radish plants.

The piosonous effects on plants are referred to as Phytotoxicity. Plant phytotoxicity testing onthe finished compost that contains degraded polymers can determine if the buildup of inorganicmaterials from the plastics is harmful to plants and crops and if they slow down soil productivity.[ ]45 ASTM 6002 establishes the standards for phytotoxicity testing. The ASTM proceduredetermines phytotoxicity by blending the compost containing the compostable plastic materialwith compost soil. The plant emergence survival and growth are evaluated. Three plant speciesare generally tested. The results from compost containing material are compared to compostwithout material and a soil control. [ ]46 The plant species can be tomato, cucumber, radish, rye,barley, or grass. Plant biomass tests can reveal quality differences between composts and canindicate potential plant stress induced by the compost at the given level used in the test. [ ]47

Safety assessment of the biodegradable plastics are listed on the materials safety data sheets

(MSDS) for each. The MSDS for the Ecoflex plastic states that the hot plastic can cause thermalburns, frequent or prolonged skin contact can cause irritation. However, the MSDS does notprovide any data on human or plant or aquatic toxicity. The overall health hazard for Ecoflex islisted as low. The MSDS for the Novomont Mater-Bi biodegradable plastic states that there isno evidence of harmful effects to the eyes, skin, or lungs with the product. Furthermore, theMSDS states that the Novomont product is not harmful to health if handled correctly. The MSDSfor the PLA plastic states that contact with the PLA fibers may cause skin irritation. The fibersmay causes discomfort for individuals who experience bronchitis or asma. PLA is not hazardousto skin absorption or inhalation. The overall health hazard for PLA is listed as low. The overallhealth risks for oxodegradable plastics should be very similar to polyethylene, which is very low.The health risks for PHA should also be low, though MSDS are not available. Sugar canepowder can cause respiratory irritation. The LD-50 for sugar can in rats is 29,700 mg/kg, which

translates into a lethal dosage of 50% of the rats that were given 29.7g of sugar cane per kg ofrat. [ ]48

Current Standards for BiodegradablePlasticsSeveral worldwide organizations are involved in setting standards for biodegradable andcompostable plastics, including, American Society for Testing and Materials (ASTM), EuropeanCommittee for Standardization (CEN), International Standards Organization (ISO), GermanInstitute for Standardization (DIN), Japanese Institute for Standardization (JIS), and BritishPlastics Federation. The standards from these organizations have helped the industry create

biodegradable and compostable products that meet the increasing worldwide demand for moreenvironmentally friendly plastics. [ ]49 The standards organization have worked together toprovide consistent and environmentally consistent standards. The German, United States andJapanese certification schemes are cooperating to enable international cross-certification ofproducts, so that a product certified in one of these countries would automatically be eligible forcertification in another.

In the U.S., ASTM D6400 is the accepted standard for evaluating compostable plastics. TheASTM D6400 standard specifies procedures to certify that compostable plastics will degrade in

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municipal and industrial aerobic composting facilities over a 180-day time period. [ ]50 Thestandard establishes the requirements for labeling of materials and products, including packagingmade from plastics, as "compostable in municipal and industrial composting facilities." Thestandard determines if plastics and products made from plastics will compost satisfactorily,including biodegrading at a rate comparable to known compostable materials. The standardsassure that the degradation of the materials will not contaminate the compost site nor diminish

the quality of the compost in the commercial facility resulting from the composting process.ASTM D6400 utilizes ASTM D6002 as a guide for assessing the compostability ofenvironmentally degradable plastics in conjunction with ASTM D5338 to determine aerobicbiodegradation under controlled composting conditions. ASTM 6400 specifies that a satisfactoryrate of biodegradation is the conversion of 60% of the organic carbon in the plastic into carbondioxide over a time period not greater than 180 days. If a biodegradable polymer does not meetthe requirements listed in ASTM D6400 or EN13433, then it is not considered compostable. Itmust degrade in a specified time frame without leaving any residuals in the compost. [ ]51 ASTMD6400 will be followed in the research to test the compost-ability of several rigid packagingcontainers, bags, and cutlery that claim to be made from biodegradable plastics.

Compostable plastics are being used in the United States with the help of a certification program

and the establishment of ASTM D6400 standards. BPI and the US Composting Council(USCC)established the Compostable Logo program in the United States. [ ]52 The BPI certificationdemonstrates that biodegradable plastic materials meet the specifications in ASTM D6400 andwill biodegrade swiftly and safely during municipal and commercial composting. Severaldegradable plastics, which are available for composting, are listed for 2002. [ ]53 The compostablelogo is helpful for consumers to identify which products meet the ASTM D6400 standards. [ ]54 Verification of the ASTM standard is accomplished through an independent third-partyconsultant who is selected by the manufacturer.

Biodegradation of biodegradable plastics in marine environment is based upon ASTM D6691and ASTM D7081. ASTM D6691 is a test method for determining aerobic biodegradation ofplastic materials in the marine environment by defined microbial consortium. ASTM D7081 is astandard specification for non-floating biodegradable plastics in marine environments. Both

standards also require that the amount of CO2 that is generated during the degradation process ismeasured. A test sample would demonstrate satisfactory biodegradation if after 180 days 30% ormore of the sample is converted to carbon dioxide.

In Europe, compostable plastics are being used in several applications. Compostable plastics,must comply with the European Norm EN13432, which is the criteria for compostability.EN13432 requires a compostable plastic material to break down to the extent of at least 90% toH2O and CO2 and biomass within a period of 6 months. ISO14855 standard specifies a testingmethod to evaluate the ultimate aerobic biodegradability of plastics, based on organiccompounds, under controlled composting conditions by measurement of the amount of carbondioxide evolved and the degree of plastic at the end of test.

DIN-Certco is a very well known and utilized certification system in Europe. [ ]55 Samplematerials are tested for regulated metals, organic contaminants, complete biodegradation,disintegration under compost conditions, and phytotoxicity (plant toxicity). [ ]56 The regulatedmetals and organic chemical tests ensure that neither organic contaminants nor heavy metalssuch as lead, mercury and cadmium can enter the soil via the biodegradable materials. Theprocedures for testing complete biodegradation in the laboratory and disintegration undercompost conditions ensure that materials are completely degraded during one process cycle of astandard composting plant. The DIN compostability certification is very similar to BPIcertification, which meets ASTM D-6400 standards.

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The International Standards Organization (ISO) is the world's largest developer of standards.[ ]57

ISO is a network of the national standards institutes of 157 countries who agree on specificationsand criteria to be applied consistently in the classification of materials, in the manufacture andsupply of products, in testing and analysis, in terminology and in the provision of services. ISO14855 specifies a method for the determination of the ultimate aerobic biodegradability ofplastics, based on organic compounds, under controlled composting conditions by measurement

of the amount of carbon dioxide evolved and the degree of disintegration of the plastic at the endof the test. The test method is designed to yield the percentage conversion of the carbon in thetest material to evolved carbon dioxide as well as the rate of conversion. ISO 14852 is thedetermination of the ultimate aerobic biodegradability of plastic materials in an aqueousmedium. The test method measures the evolved carbon dioxide and is similar to ASTMstandards.

The Australian standard for degradable plastics includes test methods that enable validation ofbiodegradation of degradable plastics. It is a system for certification of degradable polymers thatconform to the standard, e.g., EN 13432. [ ]58 The standard provides coverage to the range ofpotential application areas and disposal environments in Australia. The standard is not so severeas to exclude Kraft paper as do some European standards. Kraft paper is excluded as a positive

control due to the potential presence of sulfonated pollutants. A more effective positive controlcan be either cellulose filter paper or microcellulose AVICEL PH101. The standard wasdeveloped with reference to the existing international standards. The standard differentiatesbetween biodegradable and other degradable plastics, as does ASTM D6400, and clearlydistinguishes between biodegradation and abiotic disintegration even though both degradationsystems demonstrate that sufficient disintegration of the plastic has been achieved within thespecified testing time. The standard addresses environmental fate and toxicity issues, as doesASTM D5152. Lastly, the Australian standardis more restrictive than ASTM D-6400 andstatesthat total mineralization is required, where all of the plastic is converted to carbon dioxide,water, inorganic compounds and biomass under aerobic conditions, rather than disintegrationinto finely indistinguishable fragments and partial mineralization. [ ]59

Standards Australia Incorporated is developing two separate standards for compostable and

oxodegradable materials. The draft standards are based upon established international standards.The DR 04425CP standard is based on ISO 14855-99 standard for the determination of theultimate aerobic biodegradability and disintegration of plastic materials under controlledcomposting conditions. The DR 04424CP standard is the determination of the ultimate aerobicbiodegradability and disintegration of plastic materials in an aqueous medium. The differencebetween the two standards in the environment where one is for compost soil and the other one isfor marine environment. The standards committee has established two subgroups to develop thestandards; one for biodegradable plastics and the second group for other types of degradableplastics, including oxo-degradable and photodegradable plastics. [ ]60

The Japanese JIS standards are met with a GreenPLA certification system. The GreenPLAsystem has very similar testing requirements as the US and European certification methods. In

particular, the GreenPLA certification assures biodegradability by measuring carbon dioxideevolution after microbial biodegradation, mineralization by the ability to disintegrate and nothave visible fragments after composting, and organic compatibility by the ability of the compostto support plant growth. The same amount of carbon dioxide evolution (60%) is required forcertification. The same 11 regulated metals are monitred in GreenPLA as EN 13432. However,several aspects of the certification are different than the US BPI and European Din-Certcocertifications. GreenPLA certification requires toxicological safety data on the biodegradableplastic material from either oral acute toxicity tests with rats or environmental safety tess withalgae, Daphinia, or fish. [ ]61

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The heavy metal limits in the European standard are more stringent that those listed in the USstandards. Heavy metal concentrations in the EN13432 standard allows a limited amount ofmetal, i.e., lead (30 mg/kg), cadmium (0.3 mg/kg), chrome (30 mg/kg), copper (22.5 mg/kg),nickel 15 mg/kg), zinc (100 mg/kg), and mercury (0.3 mg/kg). The US standard allows thefollowing amounts: lead (150 mg/kg), cadmium (17 mg/kg), chrome (Not Specified), copper(750 mg/kg), nickel 210 mg/kg), zinc (1400 mg/kg), and mercury (8.5 mg/kg).[ ]62 Acceptable

levels of heavy metals in sewer sludge are provided perUS EPA Subpart 503-13. Testing of fivebiodegradable garbage bags found the heavy metal content lower than allowable standards.Pigments with green and blue colors cause the amount of copper to increase in soil. [ ]63 Pigmentsof heavy yellow can cause the amount of lead to increase in soil.

Experimental Work

Testing PlanThe degradable materials will be tested for biodegradation with three methods. The first testmethod follows the ASTM D6400 standards. All of the different types of degradable plastics,

including, oxo-degradable, biodegradable, and compostable will be monitored for biodegradationby measuring the CO2 evolution for 45-days. Also, the compost soil will be tested for heavymetals and phytotoxicity. The second test method will use aerobic in-vessel composting at theuniversity farm and a commercial compost site in Vacaville, CA. Only, compostable plasticmaterials with BPI certification and food waste will be biodegraded with this method. The thirdmethod is anaerobic in-vessel composting of compostable plastics and food waste at acommercial compost site in Los Angeles. Degradable materials will not be composted with thein-vessel compost methods due to the potential contamination of the compost from residual non-degraded plastics.

Composting is a well-accepted process of biodegrading organic materials. The compost can beproduced with three techniques, namely, aerated static pile, turned windrow, or in-vesselcontainer. Windrows are long piles, up to 2 meters high, of the compost. Static windrows are notturned or moved until composting is completed. Turned windrows are aerated by periodicmechanical mixing with a large auger. In-vessel composting places the material in a tank, wherethe compost material is aerated and mixed by tumbling or stirring. Composting in a vessel ismuch faster than traditional windrow methods. [ ]64

The first two methods are performed in the open air, or aerobic, environment. The in-vesselmethod can operate aerobically or anaerobically_ without air. The most common composttechnique is windrow type, which can be used for green yard waste. The windrow method is notused for food waste due to odors and long time required for composting. The in-vessel systemsare used in applications where land space is limited, and work well for food waste, includinganimal products and sewage. The in-vessel process produces heat, which destroys pathogens,including E. coli and salmonella bacteria. The result is a stabilized compost product that can be

used as mulch, soil conditioner, and topsoil additive. In-vessel systems can be used to compostyard waste, food, sewage sludge, mixed wastes, and paper to produce a marketable, high qualityproduct. Under optimum conditions, materials degrade aerobically in a tank. Consideredadvanced technology compared to other composting methods, in-vessel systems require precisetemperature and oxygen control.

The 1-week case study at CSU, Chico will dispose of the food waste and compostable productsat the University Farm. The materials will be composted with an in-vessel aerobic method. The

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quality of the compost will be monitored for temperature, pH, moisture, and pathogens. Theanaerobes will be treated aerobically to allow it to be used for compost at the farm.

The second case study will occur at the Mariposa Compost facility which processes municipalsolid waste (MSW) for Mariposa county, including Yosemite National Park. The in-vesselsystem is state-of thart technology. Food and compostable waste can also composted with a New

Zealand in-vessel process, called Hot Rot Composting Systems.[ ]65

The in-vessel systemprovides sufficient oxygen for aerobic degradation, while maintaining sustained temperature inexcess of 55C for three days to achieve sanitization and odor control. The quality of thecompost will be monitored for temperature, pH, moisture, and pathogens.

Anaerobic digestion will be studied with UC Davis and Dr. Zhang. Marine testing will bestudied per ASTM standards. Contamination studies will research the effects of degradableplastics on the recycling stream.

The testing in this research occurs in a laboratory setting, at a pilot scale facility at CSU, Chicoand at a commercial compost facility in Chico. The laboratory operation is an improvement onthe one used during Compostable study research at Chico State. The compost facility at theCSU, Chico University Farm simulates a pilot scale operation. The laboratory and pilot-scale

methods provide evaluation of the inherent biodegradation of plastic products in compostenvironments. The lab datacan provide indications of how the polymers will degrade in full-scale operations. The third method to test for degradation is at a full-scale, commercial compostfacility, namely, the City of Chico municipal compost facility. The full-scale test can confirmthe compostability of the biodegradable plastic materials in a large-scale operation.

The first testing environment is under controlled laboratory settings. The closely monitoredenvironment allows measurement of the degradation rate of the compostable materials as well ascontrol of important laboratory conditions, such as, compost temperature, moisture, and pH. Thepurpose of the laboratory experiment is to compare the degradation rates of several compostablematerials with known compostable standard materials, as well as to assess toxicity of thedegradation products from the compostable plastics. The experiment will use ASTM D6400laboratory protocols, though, the successful materials will not be certified to meet the ASTMD6400 standards since the laboratory is not ASTM certified. The laboratory may be ASTMcertification in the future if sufficient funding is acquired.

Biodegradation can be measured at a chemical level by monitoring the conversion of starch inthe plastics to carbon dioxide. The compostable plastic materials are exposed to mature compostat a constant temperature and moisture level over a 45-day period. Mature compost of 18-monthsis used to insure that the degradation is due to the conversion of the compostable plastic and notfrom degradation of organics in the soil. The inoculum soil, defined as compost material that iscomprised of soil and green yard waste, were screened with a sieve of less than 10 mm toremove the large pieces. The test is an optimized simulation of intensive aerobic compostingwhere the biodegradability of the samples is determined under moist conditions.

MaterialsThe materials are all commercially available plastics that are made from corn, polylactic acid(PLA), or sugar cane. The compostable materials that were added to compost in the laboratoryexperiment were representative samples ofa plate made from sugar cane, a trash bag made fromcorn, and a clear clamshell container and a cup made from NatureWorks polylactic acid (PLA).The compostable materials are described more fully in Table 2.

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Experimental Methods and Procedures

The biodegradation of the compostable materials was tested in a controlled experimentalenvironment. The experimental set up for the laboratory experiment is based upon proceduresoutlined in ASTM D5338. The procedures to measure the gases were done with detectors asallowed in the ASTM standards. Also, moist air was introduced to the top of the container rather

than at the bottom. Each of the compostable materials was added to compost soil in a 2-literglass-canning jar and placed in an oven maintained at 58C. The room temperature was between

23C and 25C during the course of the experiment. The jar containers have a rubber seal on thetop. The lid of the jars was modified to add two rubber stoppers with 5 mm tubes for moist airsupply and gas withdrawal.

The experimental set-up is described in Figure 1. Shop air is first sent to a CO2 scrubber toremove CO2, H20, and other gases from the air. It is then sent to an aluminum cylinder withwaster in the bottom to moisten the air. Moist air was then sent to a manifold that distributed themoist, CO2 free air to 42 jars in the oven. The return gases are sent to a bank of 42 gas valves.Each valve is opened to send the biogas from each jar to a gas manifold and then to a 320-mlsample jar that hold the Pasco CO2 detector. The gas manifold and sample jar are purged withroom air between each measurement. The measurement cycle takes approximately 30 minuteswith all of the 42 jars measured every 24 hours.

Laboratory Environment

Carbon dioxide and oxygen were measured with a sensors from Pasco company. The gassensors measure carbon dioxide or oxygen concentrations in an enclosed 320-ml measurementbottle. The gas sensors use infrared detection to measure the energy absorbed by carbon dioxideor oxygen molecules and then display the appropriate concentration. The carbon dioxideconcentration is expressed in parts-per-million (ppm).The CO2 gas sensor has arange between 0ppm and 300,000 ppm with accuracy of 100 ppm or 10% of value for range of 0 to 10,000 ppm,whichever is greater. It has 20% of value accuracy for range between 10,000 and 50,000, andqualitative only for values between 50,000 and 300,000. The CO2 sensor is calibrated with

sampling outside air at 400 ppm. The operating temperature range is 20C to 30C.The oxygen sensor measures the percentage of oxygen that is present in the container. The

detection error of the sensor is +/-1%. The highest concentration of gas is in the composting jarin the oven. The concentration in the composting jar is out of the range for the detector. The gasfrom the composting container is withdrawn with the 40-ml sampling syringe and diluted withroom-air CO2 concentrations in the 320-ml measurement bottle. The gas concentration readingsthen must be converted back to the appropriate concentration from the compost container. Also,ppm concentrations in the composting vessel must be converted into g of CO2 and then to g ofcarbon as described in Appendix A.

The test procedures are an improvement on the previous research on compostable plastics. Thenew procedures have better moisture control and automated CO2 measurement. In the new

procedures, 100 g of trash bag samples were added to 600 grams of mature soil compost in a 3.7L glass jar. As in the previous test, the moisture content is 50% and the temperature is held at

58C for 45-days. Preliminary results are provided in this report to establish the biodegradationcapability of the biodegradable plastic bag. In the new experiment, the jars are fed with moist airas the biogas is withdrawn with the aid of a vacuum pump. The test apparatus can test 42 jars inseries and is computer controlled with LabView data acquisition system. The CO2 is measuredwith Pasco IR detectors, as previously described, and the CO2 concentration output is saved in acomputer file for each sample jar. The Biobag biodegradable trash bag was tested with Kraftpaper control and blank compost control.

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The trash bag degraded during the test and met the compostability standards specified by ASTM.The trash bag was retested with improved test methods at a later date and was found to havedegradation similar to the Kraft paper control over the 45-day test period. The materials weretested in triplicate. Figure 2 depicts the CO2 concentration versus time for one biodegradabletrash bag sample after 3 weeks. The figure illustrates a delay period when the biogas is beingpulled from the sample jar followed by a steady increase of CO2 concentration as the biogas is

pulled through the detector. The slope of the ppm-time curve is the rate of carbon dioxide addedto the detection jar during the experiment. The rate also indicates the concentration of carbondioxide in the sample jar as well as the biodegradation of the test samples. Table 6 lists the CO2rate for Kraft paper and biodegradable trash bag over the first 21 days of the experiment. Thetables shows that the biodegradable trash bag exhibits on average 85% of the concentration ofCO2 as Kraft paper. Thus, the biodegradation rate of the biodegradable trash bag is similar to thebiodegradation of Kraft paper for the first 21 days. Biodegradation results of the biodegradabletrash bag are shown in Figure 7 to meet the ASTM D-6400 standards of 60% biodegradation.

The moisture content of the compost is maintained between 45% and 55%. At regular intervals,45-ml of gas is withdrawn from the top of the jar with the use of a syringe and placed inmeasuring container for the carbon dioxide sensor. The sampling tube was 5-mm in diameter and

approximately 200-mm long. The sampling schematic is shown in Figure 2. Carbon dioxide ismeasured at daily intervals. Oxygen was measured as needed to ensure that the content wasgreater than 6% in the containers. Three replicates of each sample were used in the experiment.

The samples were prepared with mature compost (18-months old) with a pH of 8.7, ash contentof 35%, Carbon/Nitrogen (C/N) ratio of 10. The C/N ratio was calculated based upon carbondioxide and ammonia measurements taken with the Solvita instrument on the compost at thebeginning of the test. Solvita is an easy-to-use test that measures both carbon-dioxide (CO2) andammonia (NH3) levels in the soil and also indicates a Maturity Index value. The index is usefulfor maturity level of the compost soil. [ ]66 The inoculum soil was screened with a sieve of lessthan 10 mm. The dry solids content was 95% and the volatile solids was 63%. The volatile solidspercentage is calculated by the ratio of the difference between the dry weight and the ash contentdivided by the dry weight.

Figure 1. Experimental set-up for laboratory environment.

Wet airvoid of CO2

Computer

CO2 or O2

Detector

Biogas

42 Jars at 50C for 45

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Figure 2. CO2 ppm concentration of BioBag trash bag after 21 days.

Carbon Dioxide Concentration

BioBag Trash Bag

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ppm Series1

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Cellulose filter paper (Cellupure filter) from FilterQueen and Kraft paper were used as positivecontrol m

evaluation of degradable plastic packaging

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