Lifecycle Analysis of Chinese Food Take-Out Containers

Engs 171 Industrial Ecology

May 24, 2007

Sandy Beauregard

Richard Bi

Hillary Price

Mike Zargham

1

Background

There are 36,000 Chinese restaurants in the U.S.1 Four main types of containers:

paperboard, plastic soup, plastic entrée, and plastic / aluminum entrée, are used to

transport food to customers’ homes. Each year approximately 936 million paperboard

containers, 187 million soup containers, 374 million plastic entrée containers, and 374

million plastic / aluminum entrée containers are used.2 These numbers correlate to

paperboard containers making up 50% of the market, soup containers comprising 10% of

the market, and plastic and plastic / aluminum containers each making up 20% of the

market.

Methodology

A cradle to grave analysis was performed for each of the four container types.

The analysis included the amount of resources consumed for each container’s production,

production impacts, global warming potential, energy consumption, transportation

impacts, and disposal impacts. Production impacts included air emissions (not including

greenhouse gases), water pollution, and solid waste production. Global warming

potential consisted of the CO2 equivalent of the amount of greenhouse gases produced

during each container’s entire lifecycle. Energy consumption included the energy needed

to extract raw materials and produce each container, since no energy is required to use the

container. Transportation impacts were added to global warming potential. For disposal

it was assumed each container was recycled at a rate of 10%3, and the remaining 90%

was landfilled.

Aluminum / Polystyrene Analysis

The bottom of this container is made of aluminum and weighs 14.19 grams. The

polystyrene lid weighs 7.03 grams. The total container weight is 21.22 grams, and it

holds 32 ounces. The aluminum lifecycle consists of bauxite mining, alumina

1 Luo, Michael 2 Numbers extrapolated from data provided by Martin Wai, a Chinese restaurant owner. Numbers may be low estimates due to the restaurant’s location in rural Maine. 3 Each material is recycled at an average rate of 10-20%. It was assumed these materials are recycled at a rate lower than average due to the nature of their use; people are less likely to clean out dirty containers if they have food left in them.

2

production, anode production, aluminum smelting, aluminum ingot casting, distribution

to Chinese restaurants, consumer use, and disposal (either recycling or land-filling). The

polystyrene lifecycle consists of crude oil extraction and production then petroleum

refining, as well as natural gas production and processing. After petroleum refining and

natural gas processing, material processing occurs, followed by polystyrene resin

manufacturing, distribution to Chinese restaurants, consumer use, and disposal (either

recycling or land-filling). See tables 1-4 below for details of the aluminum / polystyrene

container impact analysis.

Table 1: Aluminum Impact Summary Air emissions lb/1000lb Water Pollution lb/1000lb

Carbon monoxide 67.8 Acid 0.12 Chlorine 1.76E-02 Ammonium (NH4+) 0.001 COS 1.12E+00 BOD 0.057

Fluorides 1.92E-02 Calcium ion 0.011 HCN 3.68E-02 Chlorine ion 0.031 Hydrogen fluoride (HF) 6.45E-01 COD 0.46

Lead 9.37E-06 Cyanide (CN-) 2.10E-04 Mercury 4.00E-05 Detergents 6.10E-04 Metals 1.45E-05 Dissolved chlorine 2.10E-01

Nonmethane hydrocarbons 1.11E+00 Dissolved organics 1.40E-02 Organics 1.11E-02 Dissolved solids 2.80E-01 PAH 1.51E-01 Fluorides 6.10E-02 Particulate matter (unspecified) 1.75E+01 Hydrocarbons 1.40E-05 PFC 3.82E-01 Iron 3.30E-03

Sulfur oxides (SOx) 1.85E+01 Lead 7.80E-06

SUM 107.2927639 Magnesium ion (Mg++) 2.10E-03

SUM (kg/kg) 0.107292764 Mercury 1.60E-06

Metals 1.50E-01

Nitrate (NO3) 9.60E-04

Solid Waste lb/1000lb Oil & Grease 3.90E-02

Solid waste 2885 Other Nitrogen 1.30E-05 SUM (kg/kg) 2.885 Phenol 1.80E-04

Phosphates 1.10E-05

Sodium ion (Na+) 3.79E+00

Sulfate (SO4-) 1.00E-02

Sulfur 5.70E-04

Suspended solids 4.00E-01

SUM 5.6419774

SUM (kg/kg) 0.005641977

Global Warming lb/1000lb kg/kg CO2 Equivalent

3

Carbon dioxide 1.70E+03 1.698 1.698 CFC/HCFC 1.21E-01 0.000121 0.8591

Methane 6.22E-02 0.0000622 0.0006842 Nitrogen Dioxide (N2O) 1.96E-03 0.00000196 0.0005292

SUM (CO2 eq) 2.5583134

Resources kg/kg Bauxite-rich soil 5274 lb/1000lb 5.274 Caustic soda 143 lb/1000lb 0.143 Lime 88.2 lb/1000lb 0.0882 Crude oil 507 lb/1000lb 0.507

Coal 16.6 lb/1000lb 0.0166 Coke 0.0026 lb/1000lb 0.0000026 Distillate Oil 10.04 kg/1000lb 0.022134039

Gasoline 0.545 kg/1000lb 0.001201499 Natural Gas 195 kg/1000lb 0.42989418 Propane/LPG 1.569 kg/1000lb 0.003458995

Residual Oil 90.28 kg/1000lb 0.199029982

2.994313106 SUM (kg/kg) 6.684521295

Energy kWh/1000lb kJ/kg Electricity (bauxite production) 0.83 6587.301587 Electricity (alumina production) 95.5 757936.5079 Electricity (anode production) 53.9 427777.7778 Electricity (aluminum smelting) 6992 55492063.49

Electricity (ingot formation) 95.8 760317.4603

SUM (kJ/kg) 57444.682 Table 2: Polystyrene Impact Summary Air Emissions lb/1000lb lb/1000lb

1,3 Butadiene 1.05014E-06 Fluorides 6.41412E-06

2,4-Dinitrotoluene 1.02427E-11 Furans (unspecified) 3.42652E-10

2-Chloroacetophenone 2.56067E-10 HCFC/HFCs 0.001000555

5-methyl Chrysene 1.6552E-09 HCl 0.095389114

Acenaphthene 3.83705E-08 Hexane 2.45092E-09

Acenaphthylene 1.88091E-08 HF 0.011283902

Acetophenone 5.48714E-10 Hydrocarbons (unspecified) 1.777499142

acrolein 4.42215E-05 Hydrogen 0.000846845

Aldehydes (Acetaldehyde) 3.57361E-05 Indeno(1,2,3-cd)pyrene 4.58942E-09

Aldehydes (Formaldehyde) 0.001362412 Isophorone 2.12169E-08

Aldehydes (Propionaldehyde) 1.39008E-08 Kerosene 0.000104177

Aldehydes (unspecified) 0.004219544 Lead 4.8447E-05

Ammonia 0.016642782 Magnesium 0.0008276

Ammonia Chloride 5.79961E-05 Manganese 6.82373E-05

Anthracene 1.57996E-08 Mercaptan 7.43276E-06

Antimony 1.38977E-06 Mercury 1.02187E-05

4

Arsenic 4.20871E-05 Metals (unspecified) 0.000192278

Benzene 0.05075409 Methyl Bromide 5.85295E-09

Benzo(a)anthracene 6.01891E-09 Methyl Chloride 1.93879E-08

Benzo(a)pyrene 2.85898E-09 Methyl Ethyl Ketone 0.000260014

Benzo(b,j,k)fluroanthene 8.276E-09 Methyl Hydrazine 6.21876E-09

Benzo(g,h,i) perylene 2.03138E-09 Methyl Methacrylate 7.31619E-10

Benzyl Chloride 2.56067E-08 Methyle Tert Butyl Ether (MTBE) 1.28033E-09

Beryllium 2.20954E-06 Methylene Chloride 5.82892E-05

Biphenyl 1.27902E-07 Naphthalene 1.49343E-05 Bis(2-ethylhexyl) Phthalate (DEHP) 2.67041E-09 Naphthanlene 9.78073E-07

Bromoform 1.42666E-09 Nickel 0.000590052

Cadmium 1.88866E-05 Organics (unspecified) 0.029563614

Carbon Disulfide 4.75552E-09 Other Organics 0.01055475

Carbon Monoxide 12.36501671 Particulates (PM10) 0.199375384

Carbon Tetrachloride 2.03454E-07 Particulates (PM2.5) 0.008141081

Carbon Tetrachloride 8.31563E-09 Particulates (unspecified) 0.494803786

Chlorobenzene 8.04781E-10 Perchloroethylene 3.75133E-06

Chloroform 2.15828E-09 Phenanthrene 2.03138E-07

Chorine 0.000137248 Phenols 2.74125E-05

Chromium 4.08813E-05 Polyaromatic Hydrocarbons (total) 6.20098E-06

Chromium (VI) 5.94367E-06 Propylene 6.95192E-05

Chrysene 7.52364E-09 Pyrene 2.4828E-08

Cobalt 4.73313E-05 Radionuclides (unspecified) 0.005876995

Copper 6.25795E-07 Selenium 0.000104057

Cumene 1.93879E-10 Styrene 9.14524E-10

Cyanide 9.14524E-08 Sulfur Dioxide 14.97118097

Dimethyl Sulfate 1.75589E-09 Sulfur Oxides 14.85758707

Dioxins (unspecified) 7.66858E-09 TNMOC (unspecified) 0.008153988

Ethyl Chloride 1.5364E-09 Toluene 0.078105181

Ethylbenzene 0.006045341 Trichloroethane 7.75405E-08

Ethylene Dibromide 4.38971E-11 Vinyl Acetate 2.78015E-10

Ethylene Dichloride 1.46324E-09 VOC(unspecified) 0.974225954

Fluoranthene 5.34178E-08 Xylenes 0.045568623

Fluorene 6.84651E-08 Zinc 4.17197E-07

SUM 46.01603496

SUM (kg/kg) 0.046016035 Water Pollution lb/1000lb lb/1000lb

1-methylfluorene 8.44513E-07 Lithium 4.845041894

2,4 dimethylphenol 0.000207851 Magnesium 4.661616452

2-Hexanone 4.84518E-05 Manganese 0.008498884

2-methyl naphthalene 0.000117546 Mercury 3.76051E-06

4-methyl 2-pentanone 3.11852E-05 Metal (unspecified) 35.9350009

Acetone 7.42044E-05 Methyl Ethyl Ketone (MEK) 5.97338E-07

Acid (benzoic) 0.007527587 Molybdenum 0.000170581

5

Acid (hexanoic) 0.001558885 Naphthalene 0.00013494

Acid (unspecified) 0.002835002 n-Decane 0.000138239

Alkylated Benzenes 0.000187377 n-Docosane 5.07479E-06

Alkylated Fluorenes 1.08592E-05 n-Dodecane 0.000262288

Alkylated Naphthalenes 3.07053E-06 n-Eicosane 7.2215E-05 Alkylated Phenanthrenes 1.27315E-06 n-Hexacosane 3.16598E-06

Aluminum 0.34445657 n-Hexadecane 0.000286287

Ammonia 0.117031117 Nickel 0.001599361

Ammonium 4.65071E-05 Nitrates 0.000115777

Antimony 0.000213744 Nitrogen (ammonia) 4.05111E-05

Arsenic 0.001803418 n-Octadecane 7.07275E-05

Barium 4.856381768 n-Tetradecane 0.000114951

Benzene 0.012454703 Oil 0.163765135

Beryllium 9.03415E-05 Organic Carbon 0.012031945

BOD 1.632438037 Pentamethyl benzene 0.000138439

Boron 0.023289607 Phenanthrene 5.47493E-06

Bromide 1.590083113 Phenol/Phenolic Compounds 0.003554915

Cadmium 0.000264727 Phosphates 0.001

Calcium 23.84574999 Radionuclides (unspecified) 8.23549E-08

Chlorides (methyl chloride) 2.98669E-07 Selenium 5.79125E-05

Chlorides (unspecified) 268.0391992 Silver 0.015564147

Chromium (hexavalent) 2.58661E-05 Sodium 75.5889916

Chromium (unspecified) 0.009709506 Strontium 0.404532817

Cobalt 0.000164399 Styrene 0.000999055

COD 2.781400733 Sulfates 0.619036269

Copper 0.001488079 Sulfides 0.000932278

Cresols 0.000439679 Sulfur 0.019660016

Cyanide 1.53554E-06 Surfactants 0.006918851

Cymene 7.41523E-07 Suspended Solids 10.90586198

Dibenzofuran 1.41095E-06 Thallium 4.50732E-05

Dibenzothiophene 1.14318E-06 Tin 0.001150875

Dissolved Solids 331.6893876 Titanium 0.003283541

Ethylbenzene 0.001702432 Toluene 0.01179281

Fluorine/Fluorides 0.00075897 Total Alkalinity 0.592394577

Hardness 73.4501478 Total Biphenyls 1.21323E-05

Hydrocarbons 0.000538969 Total Dibenzo-thiophenes 3.74455E-08

Hydrocarbons 0.00001 Vanadium 0.0002015

Iron 0.781583491 Xylenes 0.006300044

Lead 0.003156547 Yttrium 5.00071E-05

Lead 210 4.92759E-13 Zinc 0.008274519

SUM 843.0163588 SUM (kg/kg) 0.843016359

Global Warming lb/1000lb kg/kg CO2 Equivalent

CO2 (fossil) 2343.323611 2.343323611 2.343323611

6

CO2 (non-fossil) 0.876645645 0.000876646 0.000876646

Methane 17.9983887 0.017998389 0.197982276

Nitrogen Oxides 5.653254631 0.005653255 1.52637875

Nitrous Oxide 0.038776605 3.87766E-05 0.010469683

CFC12 9.45E-08 9.45375E-11 6.71216E-07

SUM (C02 eq) 4.079031637

Resources Btu/1000lb kJ/kg kg/kg

Natural gas 21683124.52 50474.45145 1.173824452

Petroleum 15611386.8 36340.5276 0.845128549

SUM (kg/kg) 2.018953001

Energy kJ/kg

TOTAL 114000

Solid Waste lb/1000lb

Solid wastes, landfilled 104.4248776

Solid wastes, burned 3.340186103

Solid wastes, waste-to-energy 1.548042474

SUM 109.3131062

SUM (kg/kg) 0.109313106

Table 3: Transportation Impact Summary for Entire Container

diesel truck lb/1000gal kg/kg CO2 Equivalent

CO2 24485 0.036511684 0.036511684

methane 0.395 5.89018E-07 6.4792E-06 Nox 163.611 0.000243974 0.065873087 SUM (CO2 eq) 0.10239125

Table 4: Aluminum / Polystyrene Container Impact Summary

Resource Use

(kg/kg)

Air Emissions

(kg/kg)

Water Pollution (kg/kg)

Global Warming Potential

(kgCO2/kg)

Energy Use (kJ/kg)

Solid Waste (kg/kg)

Landfill (kg/kg)

Polystyrene 2.019 0.046 0.843 4.079 114000 0.109 0.900 Aluminum 6.684 0.107 0.006 2.558 57444.682 2.885 0.900 TOTAL 33% PS 67% AL

5.144

0.087

0.282

3.162

76107.937

1.969

0.900

7

Table 5: Air Emissions from Paperboard Production

Table 6: Global Warming Potential of Paperboard Production

Paperboard Analysis

This container is made of coated paperboard and has an aluminum handle. The

paperboard weighs 29.74 grams, and the handle weighs 2.24 grams. The total container

weight is 31.98 grams, and it can hold 16 ounces of food. The first stage in the

production of this container is logging; the wood is then sent to a mill where it is pulped

and made into paperboard. This paperboard then goes to a second manufacturing facility

that coats the paperboard and makes it into containers. The containers are then

distributed to Chinese restaurants, where they are used to deliver food to consumers, and

then go to the landfill or are recycled. For this analysis we assumed that 10% of the

containers are recycled and the remaining 90% go to the landfill. The aluminum lifecycle

was described above in the section on the aluminum / polystyrene container. The

lifecycle impacts of this container can be seen in Tables 5-9.

8

Table 7: Energy Consumption from Paperboard Production

Table 8: Toxic Releases During the Paperboard Lifecycle

Table 9: Paperboard Container Impact

Resource Use

(kg/kg)

Air Emissions

(kg/kg)

Water Pollution (kg/kg)

Global Warming Potential

(kgCO2/kg)

Energy Use

(kJ/kg)

Solid Waste (kg/kg)

Landfill (kg/kg)

Paperboard 1.720 0.039 0.00018 2.664 35508.210 - 0.900 Aluminum 6.684 0.107 0.006 2.558 57444.682 2.885 .900

TOTAL 93% Paper

7% Al 2.070 0.044 5.9 x 10-4 2.661* 37043.570 0.202 0.900

Plastic Containers Analyses

Two different plastic containers were analyzed for this project. The first is a

cylindrical-shaped 32-ounce container, typically used by Chinese take-out restaurants to

9

carry soup. This container is made of two types of plastics: the lid is made of low-density

polyethylene, whereas the body is made of polypropylene. The container weights 50.86

grams, with the lid and body accounting for 9.76 grams and 41.10 grams, respectively.

The other plastic container is a rectangular-shaped, 32-ounce container, used

primarily for larger items such as entrees. Both the lid and the body of this container are

made of polypropylene, weighing 48.23 grams total. The lifecycles of these two types of

plastics and similar to the process described previously for polystyrene. Below are

analyses of the two plastic materials, as well as the environmental impact of the two

containers.

Table 10: Low-Density Polyethylene Impact Summary Air emissions lb/1000lb Water Pollution lb/1000lb Aldehydes (Formaldehyde) 1.08E-03 Acid (benzoic) 7.05E-03

Aldehydes (unspecified) 1.18E-03 Acid (hexanoic) 1.46E-03

Ammonia 6.30E-03 Acid (unspecified) 2.24E-03

Benzene 4.01E-02 Aluminum 2.07E-01

Carbon Monoxide 5.08E+00 Ammonia 9.79E-02

Ethylbenzene 4.79E-03 Arsenic 1.60E-03

HCl 6.74E-02 Barium 3.02E+00

HF 8.23E-03 Benzene 1.17E-02 Hydrocarbons (unspecified) 1.53E+00 BOD 1.22E+00

Hydrogen 1.11E-03 Boron 2.18E-02

Nitrous Oxide 2.96E-02 Bromide 1.49E+00

Organics (unspecified) 1.18E-02 Calcium 2.23E+01

Other Organics 5.10E-02 Chlorides (unspecified) 2.51E+02

Particulates (PM10) 1.75E-01 Chromium (unspecified) 5.77E-03

Particulates (PM2.5) 6.51E-03 COD 2.15E+00

Particulates (unspecified) 3.07E-01 Copper 1.15E-03 Radionuclides (unspecified) 4.28E-03 Dissolved Solids 3.10E+02

Sulfur Dioxide 1.17E+01 Hardness 6.88E+01

Sulfur Oxides 2.31E+01 Iron 5.37E-01

TNMOC (unspecified) 5.94E-03 Lead 2.51E-03

Toluene 6.18E-02 Lithium 6.28E+00

VOC(unspecified) 1.11E+00 Magnesium 4.37E+00

Xylenes 3.60E-02 Manganese 7.78E-03

SUM 4.33E+01 Metal (unspecified) 2.84E+01

SUM (kg/kg) 4.33E-02 Nickel 1.33E-03

Oil 1.39E-01

Organic Carbon 1.03E-02

Solid Waste lb/1000lb Phenol/Phenolic Compounds 3.28E-03

Solid waste 84.131 Silver 1.46E-02

SUM (kg/kg) 0.084 Sodium 7.08E+01

10

Strontium 3.79E-01

Sulfates 5.66E-01

Resources kg/kg Sulfur 1.84E-02

Natural gas 1.535 Surfactants 6.75E-03

Petroleum 0.289 Suspended Solids 6.77E+00

SUM (kg/kg) 1.824 Titanium 1.96E-03

Toluene 1.11E-02

Total Alkalinity 5.58E-01

Energy kJ/kg Xylenes 5.91E-03

Used in production 74300 Zinc 5.19E-03

SUM 7.79E+02

SUM (kg/kg) 7.79E-01

Global Warming lb/1000lb kg/kg CO2 Equivalent

Carbon dioxide 1.44E+03 1.44E+00 1.44E+00

CFC/HCFC 1.00E-03 1.00E-06 7.11E-03

Methane 2.03E+01 2.03E-02 2.23E-01

Nitrogen Oxide 2.58E+00 2.58E-03 6.96E-01

SUM (CO2 eq) 2.369888477

Table 11: Polypropylene Impact Summary Air emissions lb/1000lb Water Pollution lb/1000lb

Aldehydes (unspecified) 1.47E-03 Acid (benzoic) 6.24E-03

Ammonia 8.26E-03 Acid (hexanoic) 1.29E-03

Benzene 2.26E-02 Acid (unspecified) 1.26E-03

Carbon Monoxide 6.13E+00 Aluminum 2.16E-01

Ethylbenzene 2.69E-03 Ammonia 8.82E-02

HCl 6.71E-02 Arsenic 1.44E-03

HF 8.14E-03 Barium 3.11E+00 Hydrocarbons (unspecified) 9.97E-01 Benzene 1.03E-02

Hydrogen 1.58E-03 BOD 1.07E+00

Nitrogen Oxides 2.54E+00 Boron 1.93E-02

Nitrous Oxide 2.43E-02 Bromide 1.32E+00

Organics (unspecified) 0.015399012 Calcium 1.98E+01

Other Organics 1.10E-02 Chlorides (unspecified) 2.22E+02

Particulates (PM10) 8.98E-02 Chromium (unspecified) 6.06E-03

Particulates (unspecified) 3.11E-01 COD 1.84E+00 Radionuclides (unspecified) 4.23E-03 Copper 1.09E-03

Sulfur Dioxide 7.26E+00 Dissolved Solids 2.74E+02

Sulfur Oxides 2.14E+01 Hardness 6.09E+01

TNMOC (unspecified) 5.88E-03 Iron 5.32E-01

Toluene 3.47E-02 Lead 2.35E-03

VOC(unspecified) 8.99E-01 Lithium 5.05E+00

Xylenes 2.02E-02 Magnesium 3.86E+00

SUM 3.99E+01 Manganese 6.95E-03

SUM (kg/kg) 3.99E-02 Metal (unspecified) 1.60E+01

11

Nickel 1.22E-03

Oil 1.24E-01

Organic Carbon 5.30E-03

Phenol/Phenolic Compounds 2.94E-03

Silver 1.29E-02

Solid Waste lb/1000lb Sodium 6.27E+01

Solid waste 83.700 Strontium 3.35E-01

SUM (kg/kg) 0.084 Sulfates 5.06E-01

Sulfur 1.63E-02

Surfactants 5.89E-03

Resources kg/kg Suspended Solids 7.00E+00

Natural gas 1.212 Titanium 2.06E-03

Petroleum 0.374 Toluene 9.85E-03

SUM (kg/kg) 1.586 Total Alkalinity 4.93E-01

Xylenes 5.23E-03

Zinc 5.33E-03

Energy kJ/kg SUM 7.65E+02

Used in production 98000 SUM (kg/kg) 7.65E-01

Global Warming lb/1000lb kg/kg CO2

Equivalent

Carbon dioxide 9.91E+02 9.91E-01 9.91E-01

CFC/HCFC 4.69E-08 4.69E-11 4.69E-08

Methane 1.70E+01 1.70E-02 1.87E-01

Nitrogen Oxide 2.43E-02 2.43E-05 2.43E-02

SUM (CO2 eq) 1.202

Table 12: Plastic Containers Impact Summary Resource

Use (kg/kg)

Air Emissions

(kg/kg)

Water Pollution (kg/kg)

Global Warming Potential

(kgCO2/kg)

Energy Use

(kJ/kg)

Solid Waste (kg/kg)

Landfill (kg/kg)

PP 1.5856 0.0399 0.7649 1.2022 98000 0.0837 0.9 LDPE 1.8242 0.0458 0.7793 2.3699 74300 0.0841 0.9 Soup

Container (80.8% PP,

19.2% LDPE)

1.6314 0.0410 0.7676 1.5288 93450 0.0838 0.9

Entrée Container (100% PP)

1.5856 0.0399 0.7649 1.3046 98000 0.0837 0.9

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Total Impact Summary

The following table compares the impact per container of each container type.

The paperboard with an aluminum handle container has the lowest impact in four of the

seven analyzed categories.

Table 13: Impact per Container Resource

Use (kg)

Air Emissions

(kg)

Water Pollution

(kg)

Global Warming Potential (kgCO2)

Energy Use (kJ)

Solid Waste (kg)

Landfill (kg)

Polystyrene/ Aluminum

0.109 0.002 0.006 0.067 1615.010 0.042 0.019

Paperboard/ Aluminum

0.066 0.001 1.8x10-5 0.085 1185.390 0.006 0.029

Plastic Entrée

0.076

0.002 0.037 0.063 4276.540 0.004 0.043

Plastic Soup

0.083 0.002 0.039 0.078 4752.968 0.004 0.045

When looking at each container’s impact across the entire market (see Table 14

below), however, the plastic soup containers have the lowest impact in four of the seven

categories. This is the case because the soup containers are the least used container type

(10% of the market), and the paperboard containers are the most used container (50% of

the market).

Table 14: Annual Market Impact Resource

Use (kg)

Air Emissions

(kg)

Water Pollution

(kg)

Global Warming Potential (kgCO2)

Energy Use (kJ)

Solid Waste (kg)

Landfill (kg)

Polystyrene/ Aluminum

4.08x107 7.48x105 2.24x106 2.51x107 6.04x1011 1.57x107 7.11x106

Paperboard/ Aluminum

6.18x107 9.36x105 1.68x104 7.96x107 1.11x1012 5.62x106 2.71x107

Plastic Entrée

2.84x107 7.48x105 1.38x107 2.36x107 1.60x1012 1.50x106 1.61x107

Plastic Soup

1.55x107 3.74x105 7.30x106 2.28x106 8.90x1011 7.49x105 8.42x106

It is also useful to compare the impact of each container per amount of food it can

hold (see Table 15). Paperboard now only has the lowest impact in one of the seven

categories. In this comparison, the polystyrene / aluminum and plastic entrée containers

have the lowest impact in the most categories.

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Table 15: Impact per Ounce Resource

Use (kg)

Air Emissions

(kg)

Water Pollution

(kg)

Global Warming Potential (kgCO2)

Energy Use (kJ)

Solid Waste (kg)

Landfill (kg)

Polystyrene/ Aluminum

3.23x10-3 5.46x10-5 1.77x10-4 1.98x10-3 47.725 1.24x10-3 5.64x10-4

Paperboard/ Aluminum

4.13x10-3 6.25x10-5 1.13x10-6 5.31x10-3 74.087 .001 1.81x10-3

Plastic Entrée

2.37x10-3 6.25x10-5 1.16x10-3 1.97x10-3 133.642 1.25x10-4 1.34x10-3

Plastic Soup

2.59x10-3 6.25x10-5 1.22x10-3 2.44x10-3 148.530 1.25x10-4 1.41x10-3

Solution Requirements

The incentives that determine what type of take-out container is used for Chinese

food restaurants in the United States are almost entirely economic. The majority of such

restaurants are small businesses that wish to buy take-out containers in large quantities.

Price is by far the most important factor. In order to be functional, a container must be

structurally sound and able to retain heat. Factors that might make containers more

attractive include collapsibility or stackability and microwavability. In addition, some

restaurant owners may wish for containers to be transparent to display the food in an

attractive manner.

These incentives can be characterized as belonging to two stakeholders: the

customers and the company. These are shared incentives because the customers want a

good product, and the company wants a product the customers will pay for. The other

key stakeholder is the environment. In general, environmental concerns do not create

strong incentives in this market. Small restaurants rarely have the luxury of worrying

about environmental concerns. A sustainable Chinese food take-out container would

have to satisfy all three of these stakeholders -- the triple bottom line must be met.

There are a wide variety of potential solutions to the take-out container problem.

The most basic solution, on the order of deep ecology, is to say “Why do we need take-

out? Growing, cooking, and eating our own food is best for the environment.” Another

possible solution is to eliminate disposable containers. A restaurant could require that

you bring some sort of container to the restaurant to collect your food. An alternate

approach to this solution is to offer a dish exchange or lease program. The customer pays

14

a deposit, and the restaurant delivers food in reusable containers. Next time you order

you can return your containers from the previous order. However, these are social rather

than technical changes, so they are not really engineering solutions.

An engineer’s solution might be to redesign the containers so that each order

could be put in one compartmentalized container. Such a container would require less

material for the same job. Another engineering approach is to consider materials more

carefully. Our analysis is aimed at determining the full lifecycle environmental impact of

current take-out containers. However, it is possible that switching to a corn based

biodegradable plastic might be considerably better. Or more simply, we could use paper

cartons and leave out the aluminum wire handle. On the other hand, it has been

suggested that we use entirely aluminum containers and require recycling.

Stakeholder-Incentive Analysis

An evaluation of these alternatives in terms of current market incentives shows

that the standard technology is strongly in place. None of the alternatives score better

than the standard containers (see Appendix A). One thing that seems possible is

removing the wire handle from the paper carton. This is shallow redesign which has

minimal improvement associated with it. To get a more sustainable alternative into the

market, there needs to be a change in the incentives to reflect the environment as a

stakeholder. This can be accomplished through government regulation. One such

regulation would be a waste tax like those beginning to appear in Europe4. Businesses

are penalized economically for generating waste. Under these incentives, a second

evaluation of the standard containers shows they are not good solutions. A new analysis

of the alternatives reveals that using biodegradable plastics or reusable containers are

better solutions (see Appendix B for analysis of incentives in a regulated market).

Using this stakeholder and incentive analysis, we have concluded that using

biodegradable plastics or reusable containers are the best potential long-term solutions

and in the meantime removing the wires from paper cartons would be good for the

environment. Up until this point, we have assumed that these alternatives are better for

4 Jacobsen and Kristoffersen

15

the environment. Now we will consider lifecycle analyses of our chosen alternatives to

verify our assumptions and to pinpoint the best alternative.

Biodegradable Plastic

This analysis is for polyhydroxyalkanoates (PHAs), a type of biodegradable

plastic. PHA, still in the early stages of development, has similar properties to

conventional plastics made from petrochemicals and is made from vegetable starch, a

renewable resource. At this point, biodegradable plastic is 2-10 times more expensive to

produce than conventional plastic5, which makes it less desirable in the application as a

container for Chinese food. PHA plastic is made from glucose from vegetable starch in a

fermentation process and is completely biodegradable.

The production process of biodegradable plastic begins with growing and

harvesting a vegetable (e.g., corn or potatoes), then processing the vegetable to yield

glucose from its starch, sterilizing the glucose and fermenting it to convert it to PHA,

washing recovered biomass by centrifugation, releasing the polymer from within cell

walls, washing the polymer by centrifugation, drying the polymer slurry and forming a

container. The lifecycle of PHA plastic consists of the aforementioned production

processes, consumer use, then disposal, during which the plastic biodegrades. See Tables

16 to 20 for details of the impact analysis of this type of container. This analysis assumes

the same amount of PHA plastic is used for the container it is replacing. See Tables 21 to

23 for the impact of replacing each type of conventional container with PHA plastic.

Table 16: PHAs Material Use6

5 “Making Packaging Greener – Biodegradable Plastics” 6 Gerngross

16

Table 17: Energy Use During Production of PHAs6

Table 18: Energy Use for Raw Material Production for PHAs6

Table 19: Total Energy Use for PHAs Production6

Table 20: Impact Summary for PHA

Resource Use (kg/kg) 2.39 Energy Use (kJ/kg) 57,807.61

Landfill (kg/kg) 0

17

Tables 21 and 22 below show the impact of replacing the plastic soup container,

plastic and aluminum entrée containers, and paperboard container with PHA plastic.

Replacing both the soup container and entrée containers with biodegradable plastic

lowers the overall impact of the container. However, replacing the paperboard container

with biodegradable plastic would not reduce the impact of that type of container.

Table 21: Impact Summary per Ounce of Food Plastic Soup Container PHA-equivalent Resource Use (kg) 2.59x10-3 3.80x10-3 Energy Use (kJ) 148.53 91.88 Landfill (kg) 1.41x10-3 0 Table 22: Impact Summary per Ounce of Food Aluminum Entrée

Container Plastic Entrée

Container PHA-equivalent

Resource Use (kg) 3.23x10-3 2.37x10-3 1.58x10-3 Energy Use (kJ) 47.73 133.64 38.33 Landfill (kg) 5.64x10-4 1.34x10-3 0 Table 23: Impact Summary per Ounce of Food Paperboard Container PHA-equivalent Resource Use (kg) 4.13x10-3 4.78x10-3 Energy Use (kJ) 74.09 115.54 Landfill (kg) 1.81x10-3 0

Paperboard Container without Aluminum Handle

The paperboard container can serve its purpose just as well without the aluminum

handle. When the handle is removed the new weight of the container is 29.74 g. The

impact of this 100% paperboard container can be seen in Tables 24 through 26. Some

interesting things to note are that the Global Warming Potential actually increases when

using only paper and the Water Pollution is reduced by nearly 70%. Table 24 shows how

this container compares to the container with an aluminum handle on a per ounce of food

basis. You can see that removing the handle results in an improvement in 5 of the 7

categories.

18

Table 24: Paperboard Container Impact (Aluminum Handle Removed)

Resource Use

(kg/kg)

Air Emissions

(kg/kg)

Water Pollution (kg/kg)

Global Warming Potential

(kgCO2/kg)

Energy Use

(kJ/kg)

Solid Waste (kg/kg)

Landfill (kg/kg)

Paperboard 1.720 0.039 0.00018 2.664 35508.210 - 0.900 % Reduced 16.9 11.4 69.5 + 0.1 4.1 100 0

TOTAL 100% Paper 1.720 .039 1.8 x 10-4 2.664 35508.210 - 0.900

Table 15: Paperboard Impact per Container

Resource Use (kg)

Air Emissions

(kg)

Water Pollution

(kg)

Global Warming Potential (kgCO2)

Energy Use (kJ)

Solid Waste (kg)

Landfill (kg)

Paperboard 0.051 1.16 x 10-3 5.35 x 10-6 0.079 1056.01 - 0.027

Table 26: Paperboard Container Impact per Ounce of Food

Resource Use (kg)

Air Emissions

(kg)

Water Pollution

(kg)

Global Warming Potential (kgCO2)

Energy Use (kJ)

Solid Waste (kg)

Landfill (kg)

Paperboard (NEW)

3.19 x 10-3 7.25 x 10-5 3.34 x 10-6 4.94 x 10 -3 66.00 - 1.69 x 10-3

Paperboard (OLD)

4.13x10-3 6.25x10-5 1.13x10-6 5.31x10-3 74.087 .001 1.81*10 -3

Using own Container

Another alternative is to have consumers bring their own container from home to

pick up food rather than having delivery with disposable containers. The impacts of this

can be seen in Tables 27 and 28. In this analysis, we made the following assumptions:

• Customer already owns containers

• The container is cleaned at home in an Energy Star dishwasher

• Soap is negligible because the consumer uses biodegradable dish soap

• The dishwasher uses 15 gallons of water per use and 341 kWh per year

• The dishwasher capacity is 40 dishes

• Chinese food accounts for 2 dishes per week.

• Each dish holds 32 ounces of food

19

Table 27: Reusable Container Impact per Container

Water Consumption (gal)

Energy Use (kJ)

Own container 0.094 36.9

Table 28: Reusable Container: Impact per Ounce of Food

Water Consumption (gal)

Energy Use (kJ)

Own container 2.93 x 10-3 1.15

Compartmentalized Biodegradable Plastic Container

Another potential solution is to use a single, compartmentalized container made of

biodegradable plastic instead of multiple containers made from different materials. It is

assumed such a container holds 50 ounces of food and weighs 75 grams (assuming PHA

plastic has a similar density to conventional plastic). Table 29 below shows the impacts

of a compartmentalized, biodegradable plastic container.

Table 29: Compartmentalized Container: Impact per Ounce of Food Resource Use (kg) 3.58x10-3 Energy Use (kJ) 86.71 Landfill (kg) 0 Comparison of Potential Solutions

Four potential solutions were evaluated: removing the aluminum wire from the

paperboard container, substituting current containers with biodegradable plastic, using a

single compartmentalized biodegradable plastic container, and using the customer’s own

dishes from home. Unfortunately, there is no easy way to compare these alternatives

directly; each alternative has advantages and disadvantages.

Bio-plastics seem like an optimal solution because they are an improvement over

standard plastics at the end of their life, but the production of bio-plastics is energy

intensive. This does not eliminate them as a good solution. This technology is still in its

infancy, and there are a great number of stages where improvements can be made. For

example, the amount of plastic material created per hectare of land and the amount of

resources needed per hectare could be improved. Also, the plastic itself could be

improved so that products require less material.

20

Bio-plastics are currently an improvement over standard petroleum-based plastics,

and they have the advantage of looking the same, allowing for an easy transition. With

advances they could offer a good long-term solution.

Creating a compartmentalized container is better than using individual containers

made of the same material. This alternative introduces an economy of scale. However,

this effect is moderate, as it can only be used when an order requires enough food to use

this container. In fact, it could be counterproductive if restaurants serve food in a

compartmentalized container without filling all of the compartments. In that case, more

material is used than needed. Used correctly, these containers would have a net

environmental benefit, but they do come at some social cost. They are less convenient to

microwave, and they make it harder for people to share an order.

Removing the metal wire from a paperboard carton is a great idea. Simply put, it

completely removes a high impact material, makes the entire product recyclable without

needing to be taken apart, and does not take away from the function of the product.

However, this is a very shallow redesign. One might think of this as doing the wrong

thing the right way. As noted, this makes it a good short-term fix but not a good long-

term solution. Furthermore, recycling of paper, while worth doing, is not an impact free

process. While this is certainly worth doing for the time being, it should not be treated as

a long-term solution.

Using your own container has the least environmental impact of any of the

alternatives considered. The impact is completely embodied by the washing process

because we assumed that customers already own the containers. Impact is mostly in the

form of energy for heating the water and the consumption of the water itself. Another

similar option is to use reusable containers supplied by the restaurant, which you would

return later. These would be washed in an industrial dishwasher with higher efficiency.

In either case, reusable containers are preferable. The biggest challenge is that this

requires a considerable change in customer behavior. Therefore, we cannot expect the

switch overnight. A good way to start would be to offer discounts to people who use

their own containers. In the framework defined by the waste tax regulation discussed

earlier, the restaurant could pass the cost on to the customer, giving them a strong

incentive to use their own reusable containers.

21

Conclusions

We conclude that the best alternative is to use reusable take-out containers. Since

this type of change cannot occur overnight, we also support the use of paperboard cartons

without wire and bio-plastic, compartmentalized containers. It would be inappropriate to

favor one of these secondary options over the other because neither is better for the

environment in all of the areas considered. Additionally, a waste tax or other regulations

may be investigated as a way of altering incentives and making sustainable options more

economically competitive with current standard containers.

22

Appendix A: Qualitative Analysis under Current Incentives A simple score based qualitative analysis of the important properties tells us that in

general the better we expect a solution to be for the environment the poorer it scores. (The

notable exception being the recycled aluminum which we think would be too energy intensive to

be worthwhile.) Nonetheless, we know that in order to get a green container to take over this

market it needs to score better than the ideas we have offered so far.

Standard Price (x5)

Structure (x3)

Heat Ret. (x3)

Micro-wave (x1)

Stacking (x1)

Behavior change

(x4)

Technical change

(x3)

Total

Plastic 1 1 1 1 0 1 1 19 Aluminum+Plastic 1 1 0 -1 1 1 1 15

Paper w/ wire 1 0 1 1 1 1 1 17

Green Price

(x5) Structure

(x3) Heat Ret. (x3)

Micro-wave (x1)

Stacking (x1)

Behavior change

(x4)

Technical change

(x3)

Total

Bring Plastic-ware 0 1 1 1 -1 -1 1 5 Paper w/o wire 1 0 1 1 1 1 1 17

Bio-plastic -1 1 1 1 0 1 -1 3 Large Container 0 1 1 0 -1 0 0 5

Recycled Al. -1 0 0 -1 1 1 0 -1 Container Exch. 0 1 1 1 -1 -1 1 5

A score of 1 represents a property that makes a product more desirable. A score of -1 represents

a property that makes the product seem less desirable and a score of 0 means that it can be

viewed as neither a pro nor a con.

23

Appendix B: Qualitative Analysis under Government Regulations

One way to change improve the outcome is to consider the same incentives under the

constraint of waste responsibility regulations. This makes wasteful options less cost effective. It

would make it much easier to get a green product on the market.

Green

w/ Regulation Price (x5)

Structure (x3)

Heat Ret. (x3)

Micro-wave (x1)

Stacking (x1)

Behavior change

(x4)

Technical change

(x3)

Total

Bring Plastic-ware 1 1 1 1 -1 -1 1 10 Paper (w/o wire) -1 0 0 1 1 1 1 4

Bio-plastic 1 1 1 1 0 1 -1 13 Large Container -1 1 1 0 -1 0 0 0

Recycled Al. 0 0 0 -1 1 1 0 4 Container Exch. 1 1 1 1 -1 0 0 12

Standard

w/ Regulation Price (x5)

Structure (x3)

Heat Ret. (x3)

Micro-wave (x1)

Stacking (x1)

Behavior change

(x4)

Technical change

(x3)

Total

Plastic -1 1 1 1 0 1 1 9 Aluminum+Plastic -1 1 0 -1 1 1 1 5

Paper w/ wire -1 0 1 1 1 1 1 7

This analysis tells us firstly that it will be very challenging to get a greener technology

adopted. In order to really make a difference we may need to wait for government regulations.

The good news is that the idea of waste responsibility is currently growing in Europe. Work to

develop bio-plastics should be continued. Regulation would be the best way to expedite the

move to greener products. However, as petroleum becomes more rare and bio-plastic technology

is improved, it is possible they may simply transition into commonplace. In the meantime we are

working on improving the standard take-out containers. Plastic containers are being reused in

homes for extended periods of time and, in some cases, recycled. We have also noted that in the

meantime, it would be feasible to phase out the wire handles on paper cartons.

24

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