1

Market Development and Sustainability Technical Advisory Committee

CIWMB

November 7, 2007Joseph P. Greene, Ph.D.

Professor California State University, Chico

Chico, CA  95929-0789

Performance Evaluation of Environmentally Degradable Plastic

Packaging and Disposable Food Service Ware

2

Agenda• Project 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 • Laboratory ASTM D-6400 Compost Anaerobic Digestion

– Marine Water Environment– Anaerobic Digestion Environment– Laboratory Quality Tests for Contamination of Recycled

Plastics• Conclusions and Recommendations• Questions

3

Objectives• 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 resulting

from the degradation– Mechanical and physical properties

• Recycled plastics with contamination from degradable plastics

• Other– Product performance use and cost.– Identify future research needs.

4

Definitions• Degradable plastics

– All plastics are degradable, though the mechanism is different.– Oxidation: plastics degrade in oxygen environment. Anti-oxidants are added to

polymers.– 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 consume them.

• 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.

5

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 Polymers Institute- 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

6

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, compost

maturity, and % solids.

7

Chico Green Yard Waste Compost Pictures (120 days)

OxobiodegradableCompost pile

PLA Container Biobag bag

Incoming trash

8

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 and straw, and Biobag trash bags.

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

9

In-vessel Manure and Food Waste Compost Pictures (120 days)

In-vessel Compost pile

PLA Container Biobag bag

Incoming MSW trashTurning row

10

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 and lids, and Biobag trash bags.

– 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.

11

Vacaville In-vessel Food Waste Compost Pictures (180 days) (Clarify Kraft paper fragments as wet and low

strength and lignin degradation)

In-vessel Compost pile Sugar cane lidsKraft paper

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

12

Vacaville In-vessel Food Waste Compost Pictures (180 days)

Oxodegradable bag UV-degradable LDPE stretch film control

13

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 degradation: Sugar cane lids and Kraft paper control

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

14

Mariposa In-vessel Compost Pictures

ECS In-vessel Method Inside chamber with samples

Kraft paper and sugar cane Oxodegradable bags

15

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

16

Mariposa In-vessel 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 and lids, and Biobag trash bags.

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

trash bags; LDPE control.

• Some degradation: Sugar cane lids and Kraft paper control

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

17

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 acquisition system 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.

18

Laboratory Biodegradation Compost Pictures

19

45-day Degradation Results

Material Biodegradation Conversion %

Degradation rate g/day

Results

Cellulose positive control 71.99 0.016 Pass

Kraft paper positive control 61.91 0.014

Pass

PHA bag 64.03 0.014 Pass

PLA straws 61.22 0.014 Pass

Sugar cane plate 61.12 0.014 Pass

Biobag trash bag 60.47 0.013Pass

Ecoflex bag 60.14 0.013 Pass

Blank compost control 1.69 0.000 ----

Polyethylene negative control 1.70 0.000

Fail

Oxodegradable bag 2.19 0.000 Fail

20

Plant Growth Results

Material Average Germination %

Average Length, mm after 10-days

Average Germination

Index

Average pH Results

Compost control 46.67 24.33 11.35 8.50 Pass

Cellulose control 43.33 22.67 9.82 8.80 Pass

Avicell cellulose control 83.33 18.33 15.27 8.70

Pass

Kraft paper control 66.67 26.67 17.78 8.40Pass

Polyethylene negative control 70 25 17.50 8.63

Pass

PLA Container 70 20 14.00 8.50 Pass

Sugar Cane lid 70 14 9.80 8.77 Pass

Biobag trash bag 60 32.33 19.40 8.63Pass

PHA bag 63.33 16 10.13 8.83 Pass

Ecoflex bag 56.67 18.33 10.39 8.60 Pass

Oxo-degradable bag 73.33 18.33 13.44 8.80 Pass

21

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.

Material Average Lead

Concentration Result Average Cd

Concentration Result

Compost 0.02 mg/kg Pass .001 mg/kg Pass

Cellulose 0.02 mg/kg Pass .001 mg/kg Pass

Kraft Paper 0.02 mg/kg Pass .001 mg/kg Pass

Polyethylene 0.02 mg/kg Pass .001 mg/kg Pass

Biobag 0.02 mg/kg Pass .001 mg/kg Pass

PLA straws 0.02 mg/kg Pass .001 mg/kg Pass

Sugar Cane 0.02 mg/kg Pass .001 mg/kg Pass

Ecoflex bag 0.02 mg/kg Pass .001 mg/kg Pass

PHA bag 0.02 mg/kg Pass .001 mg/kg Pass

22

Anaerobic Digestion at UC Davis• Materials

– Kraft paper and low density polyethylene controls– Oxo-biodegradable: Ecosafe and Eco-friendly plastic trash bags– Biodegradable: Food waste and biodegradable products, i.e., PLA

lids and straws, Biobag trash bags, PHA bags, Ecoflex bags, and Stalk Market sugarcane lids.

• Methods – Per Dr. Zhang’s research from U.C. Davis– Place 1 g of sample in 1-L jar with 0.5L of water waste

and food sludge at 50°C.– Duplicate test with new samples.

• Tests– Monitor biogas production over 30 day period.

• More research is needed.

23

Anaerobic Digestion at UC Davis Pictures

24

Anaerobic Digestion at UC Davis• Results: Duplicate trial: 45 days

– (add table for %C from biogas to CO2 and CH4)

• Conclusions– Digestion occurs and biogas is generated for first 15 days. – PHA DOES continues to generate biogas and thus digest anaerobically for the next 30 days.– PLA, Ecoflex, oxo-degradable, UV-degradable, and Kraft paper DO NOT generate biogas after 15 days.

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)

Biog

as y

ield

(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

25

Laboratory Marine Testing• Materials

– Kraft paper and low density polyethylene controls– Oxo-biodegradable: Ecosafe and Eco-friendly plastic trash bags– 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 30°C.

• Ocean water was retrieved in July 2007 from Big Sur beach in California.• Water was held at 5°C until testing.

• Tests– At 30 days weigh samples after 24 hours of drying in air and then

replace water with fresh 100 ml and place in oven.– At 60 days weigh samples after 24 hours of drying in air and then

add fresh 40 ml and place in oven.– At 90 days weigh samples after 24 hours of drying in air.

• More research is needed.

26

Laboratory Marine TestingPictures

Experimental Set-up Oxo-degradable 90 days

PHA 30 days PHA 90 days

27

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 trash bags; 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.

• Some degradation: PHA bag- 60% disintegration

– 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.

• Some degradation: PHA bag- 70% disintegration

28

Laboratory Quality Tests for 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.

29

Laboratory Quality Tests for 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.

30

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 of 10 and 20 wt% • Negatively affected melt index, moisture content of HDPE.• Decreased tensile strength and impact strength of HDPE.

– Oxodegradable plastics at concentrations of 10 and 20 wt% • Negatively affected melt index, moisture content of LDPE.• Decreased tensile strength and impact strength of LDPE.

– More research is needed.

31

Results Contamination of Recycled Plastics • Mechanical tests

Material

Tensile strength

Ultimate Elongation

Tensile Modulus

Impact strength

% increase % increase % increase % increase

LDPE- neat -- -- -- --

LDPE 10%oxo 3 23 -10 -2

LDPE 20% oxo 3 29 -14 -2

LDPE 10% biobag -1 12 -14 -4

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

HDPE- neat -- -- -- --

HDPE 5% PLA -4 20 4 -31

HDPE 10% PLA -9 100 -17 -38

32

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 in commercial• 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 may fragment into smaller pieces compost environments, but may also create more SEVERE environmental consequences.

33

Conclusions• PHA degraded in marine and anaerobic

digestion environments.• Sugar cane degraded in anaerobic

digestion environment and also in marine environment.

• PLA straws, Ecoflex bag, and Biobag did not disintegrate in marine environment and biodegraded slowly in anaerobic digestion environment.

34

Conclusions• Biodegradable plastics are a contaminant

to recycled plastics.– PLA and Biobag plastics at concentrations of

10 and 20 wt% can negatively impact melt index, moisture content, tensile and impact properties.

– Contamination of biodegradable plastics can be controlled like other contaminants to recycled plastics.

35

Recommendations• The research work will help the expanded use

of compostable plastic materials for selected applications.

• The compostable materials should be certified as compostable by BPI and included in procurement standards.

• The compostable plastic materials should perform well in simple applications, e.g., food service ware, lawn and leaf refuse bags that have dry contents, grocery bags, department store bags, and pet bag products.

36

Questions?