Life cycle inventory and analysis of re-usable plastic containers and display-ready corrugated containers used for packaging fresh fruits and vegetables

PACKAGING TECHNOLOGY AND SCIENCEPackag. Technol. Sci. 2006; 19: 279–293Published online 19 April 2006 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/pts.731

Life Cycle Inventory and Analysis of Re-usablePlastic Containers and Display-readyCorrugated Containers Used for PackagingFresh Fruits and Vegetables

By S. Paul Singh,1 Vanee Chonhenchob2 and Jagjit Singh3

1 School of Packaging, Michegan State University, East Lansing, MI, USA2 Packaging Department, Kasetsart University, Bangkok,Thailand3 Orfalea College of Business, California Polytechnic State University, San Luis Obispo, CA, USA

Today’s demanding distribution challenges require engineers to choose from varioustypes of materials, design and construction methods, to develop containers thatcan deliver goods with minimal damage. The challenge is even greater whenpacking and shipping goods which are perishable and sensitive to both physicaland climatic changes in environment. In recent years the type of packagingmaterial used to design and construct containers has undergone more scrutiny thanever, due to environmental challenges. This study focuses on two types ofcontainers that have been designed and are being used to pack and ship fresh fruitsand vegetables. The study compares the re-usable plastic containers to single-usedisplay-ready paper corrugated trays. Results show that, based on the scope of thisstudy and comparing 10 different produce items, such as apples, carrots, grapes,oranges, onions, tomatoes, strawberries, etc., the re-usable plastic containersrequire 39% less total energy, produce 95% less total solid waste and generate 29%less total greenhouse gas emissions. This study focused on the North Americanmarket. Major European nations have been using a large number of re-usableplastic containers for these types of fresh produce for the past three decades. Thisstudy was initiated by the Franklin Associates, an independent consulting firm forallowing an in-depth review of all data and results from a two year study titled:Life Cycle Inventory of Reusable Plastic Containers and Display-ReadyCorrugated Containers Used for Fresh Produce Applications. Copyright © 2006John Wiley & Sons, Ltd.Received 23 September 2005; Revised 7 December 2005; Accepted 27 January 2006

KEY WORDS: life cycle inventory; packaging; re-usable plastic containers; paper corrugatedtrays

* Correspondence to: S. P. Singh. School of Packaging, Michegan State University, East Lansing, MI, USAE-mail: [email protected] authors would like to acknowledge the Reusable Pallet and Container Coalition (RPCC) and Franklin Associates, an independent consulting firm for allowing an in-depth review of all data and results from a two year study titled: Life Cycle Inventory of Reusable Plastic Containers and Display-Ready Corrugated Containers Used for Fresh Produce Applications.13

Copyright © 2006 John Wiley & Sons, Ltd.

INTRODUCTION

Among the tools available to evaluate environ-mental performance, life cycle assessment (LCA)provides an holistic approach to evaluate environ-mental performance by considering the potentialimpacts from all stages of manufacture, productuse and end-of-life stages, sometimes called the‘cradle-to-grave’ approach. LCA is described byISO 14040.1; there have been additional updates inISO 14041, 14042 and 14043 regarding the structureof LCA. Draft 14040.11 is ‘a systematic set of pro-cedures for compiling and examining the inputsand outputs of materials and energy and the asso-ciated environmental impacts directly attributed tothe functioning of a product or service systemthroughout its life cycle’. LCA attempts to predictthe overall environmental burdens associated withthe provision of the product and identify particu-larly burdensome or wasteful processes therein.The four linked components of LCA are describedin Figure 1.2

Life cycle inventory (LCI)

LCI quantifies material use, energy use, environ-mental discharges and wastes associated with eachstage of a product system over its life cycle, fromraw material extraction through material process-ing, product fabrication, use, re-use or recyclingand ultimate disposal. The result is a cradle-to-grave inventory of energy use, solid wastes andindividual atmospheric and water-borne sub-stances released over the life cycle of the definedproduct system(s). Life cycle assessment (LCA)attempts to classify and characterize the potentialimpacts of inventory releases on human health andthe environment. For example, the life cycle inven-tory of a product system would identify and quan-tify the emissions of various substances released toair and water over the life cycle of the productsystem. Releases of certain substances to theatmosphere contribute to ozone depletion, whilespecific water-borne releases may cause eutrophi-cation of bodies of water. A variety of atmospheric

S. P. SINGH ET AL.Packaging Technologyand Science

Copyright © 2006 John Wiley & Sons, Ltd. 280 Packag. Technol. Sci. 2006; 19: 279–293DOI: 10.1002/pts

LIFE CYCLE ASSESSMENT

Goal definition and scoping: identifying the LCA's purpose andthe expected products of the study, and determining the boundaries

(what is and is not included in the study) and assumptions basedupon the goal definition

Life-cycle inventory: identifying and quantifying the energy andraw material inputs and environmental releases associated with each

stage of production

Impact analysis: assessing the impacts on human health and theenvironment associated with energy and raw material inputs and

environmental releases quantified by the inventory

Improvement analysis: evaluating opportunities to reduce energy,material inputs, or environmental impacts at each stage of the

product life-cycle

Figure 1. Life cycle assessment components.2

and water-borne substances may contribute tohuman health impacts. LCA first classifies theinventory list of emissions into the categories inwhich they may cause impacts; then category indicators, characterization models, equivalencyfactors and weighting values may be applied totranslate the releases into potential impacts in eachcategory.

Between the increasing consumer demands,improved packing and packaging techniques, andstreamlined supply chain solutions, the dynamicUS produce industry has experienced a constantgrowth in the past few decades. In 2003, the $94.5billion US fresh produce industry was sharedbetween the food service industry ($42 billion),retail industry ($51.1 billion) and farm and publicmarkets ($1.4 billion).3 Produce consumptionincreased 3% in 2004.4 Consumers are alsodemanding greater variety. In 1994, small andlarge supermarkets stocked less than 350 produceitems. Last year, large supermarkets stocked 558items and small supermarkets stocked about 540items. Figure 2 shows a steady increase in percapita consumption of fresh produce in the USduring 1980–2002.5 The fresh produce industry hasstrongly campaigned to show that the consump-tion of fresh fruits and vegetables promotes ahealthy lifestyle.

The US market for produce packaging is pre-dicted to grow 5.1% annually through 2008, basedon healthier eating trends and rising demand forfresh-cut, ready-to-eat produce.6 In the $2.8 billionUS fresh produce packaging segment,6 when con-

sidering a transport package for fresh produce, re-usable plastic containers (RPCs) and display-readycommon footprint corrugated containers (DRCs)are among the top two choices for both the retailand food service industries (Figures 3, 4). RPCs,due to the push for their use by Wal-Mart StoresInc. and HEB Produce Co., have gained a signifi-cant presence since 1998. According to one study,7

DRCs are now used to ship 26% of the retailproduce volume, with the RPCs accounting for 8%.In addition, new packaging concepts have beendeveloped that show the use of plastics and papercorrugated together, where the plastic part is re-usable in the application of flowers for retail(Figure 5). Based on the data collected by the Re-usable Pallet and Container Coalition, the esti-mated number of RPCs in the USA in 2005 was 40million for fresh produce. The average inventoryturn among four leading RPC providers is four peryear. This number is increasing each year, as theindustry refines the process of asset flow through


LCA OF FRESH FRUIT AND VEGETABLE CONTAINERS Packaging Technologyand Science

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1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002

Figure 2. Per capita US fresh fruit and vegetableconsumption.4

Figure 3. Sample of RPC with apples.

Figure 4. Sample of DRC with tomatoes.

the supply chain. The types of container comparedin this study are shown in Figures 3 and 4.

Due to the ever-increasing demand for DRCsand RPCs in the supply chain, an analysis was con-ducted of the two types of packaging used forshipping fresh produce. The analysis includes dif-ferent sizes and weights of containers used in 10produce applications. This study of the two typesof containers is a LCI which identifies and quanti-fies energy and material inputs and emissions tothe air, water and land over the life cycle of aproduct system. The life cycle steps analysed inthis study include extraction of raw materials fromthe earth, materials and container manufacture,outgoing transportation of containers, backhaul-

ing and washing of empty RPCs, recycling ofDRCs and RPCs, and end-of-life disposition. Thus,the study is a full systems analysis for the entiresupply chain for the two types of containers and is consistent with the methodology of LCI8 asdescribed by the Society of Environmental Toxi-cology and Chemistry (SETAC) and in ISO 14040and 14041 Standard documents. Figure 6 illustratesthe general approach used in an LCI analysis. Thediscussion of LCI results focuses on energy use,greenhouse gases (GHG) release and solid waste.

The authors have also previously tested andevaluated RPCs with other styles of plastic cratesand corrugated boxes, based on damage to tropi-cal fruits such as mangoes and papayas.9,10 Theresults from these studies show a reduceddamaged rate in RPCs, especially when going to asingle-layer fruit. The RPCs also showed betterpre-cooling rates due to the increased venting area.In another study, comparing both plastic andpaper corrugated trays for mail applications,11 theplastic trays showed a significant higher trip lifeand therefore more re-use than paper corrugatedtrays.

PURPOSE OF THE STUDY

The purpose of this study is to identify and quan-tify the energy, solid wastes and atmospheric and



Raw Materials Acquisition

Materials Manufacture

Product Manufacture

Product Use or Consumption

Final Disposition –Landfill,

Combustion, Recycle or Re-use

Energy Energy Energy Energy

Wastes WastesWastesWastes Re-use

Product Recycling One or limited number of return cycles into product that is then disposed = open-loop recycling

Repeated recycling into same or similar product, keeping material from disposal = closed-loop recycling

Energy

Figure 6. General materials flow for ‘cradle-to-grave’ analysis of a product.

Figure 5. Sample of combination plastic/paper containerfor flowers.

water-borne emissions associated with RPCs andDRCs used for shipping fresh produce. Ten differ-ent high-volume fruit and vegetable (produce)applications were analysed.

SYSTEMS STUDIED

Two general types of container systems areanalysed in this study: RPCs and DRCs. Varioussizes and weights of containers are analysed in thestudy for use in the 10 fresh produce applications.The produce applications studied were selectedfrom high-volume commodities representing arange of product sizes and weights and a range ofcontainer sizes used for packing. Table 1 shows thecontainer weights and packaging data for eachfresh produce application.

The corrugated containers analysed in this studyare ‘common footprint’ containers that have thesame base dimensions as RPCs; thus, the pallet andtruck loading are very similar for RPCs and DRCsin corresponding produce applications. There aresome minor loading differences due to variationsin container heights. Also, some applications reachtheir weight load capacity sooner with RPCs com-pared to corresponding DRCs, due to the heavier

container weight for RPCs. Figure 7 shows the lifecycle for DRCs.

The RPCs analysed in this study operate in aclosed pooling system. In this type of system, own-ership of the containers is maintained by a serviceprovider company (the pooler) that operatesdepots at various locations across the country. The



DRC LIFE CYCLE

DRCMANUFACTURER/SUPPLIER

USER COMPANY(manufacturer/grower)

END USER (retailer/wholesaler)

Offlo

aded

DRCs sh

ipped

back fo

r recovery an

d

recycling

New DRCs

Product loaded in DRCs

Post consumer

Industrial scrap

Virginmaterials

Table 1. Container weights and packaging

Containermovements required

Average weight per to ship 1000 tons of empty container Produce per container produce (thousand

[kg (lb)] [kg (lb)] movements)

Fresh produce RPC DRC RPC DRC RPC DRC

Apples 2.45 (5.4) 0.82 (1.8) 18.6 (41) 18.1 (40) 48.5 50.0Bell peppers 2.18 (4.8) 0.91 (2.0) 11.3 (25) 11.8 (26) 79.4 76.9Carrots 2.31 (5.1) 0.91 (2.0) 21.8 (48) 21.8 (48) 41.7 41.7Grapes 1.5 (3.3) 0.77 (1.7) 8.62 (19) 9.53 (21) 105.0 95.2Lettuce (head) 2.4 (5.3) 1.13 (2.5) 15.9 (35) 18.1 (40) 56.8 50.0Oranges 2.18 (4.8) 1.0 (2.2) 18.1 (40) 18.1 (40) 50.0 50.0Peaches/nectarines 1.59 (3.5) 0.86 (1.9) 15.4 (34) 15.9 (35) 58.4 57.1Onions 1.77 (3.9) 0.82 (1.8) 18.1 (40) 18.1 (40) 50.0 50.0Tomatoes 1.77 (3.9) 0.68 (1.5) 12.7 (28) 12.7 (28) 71.4 71.4Strawberries 1.13 (2.5) 0.41 (0.9) 4.08 (9) 4.08 (9) 222.0 222.0

Figure 7. DRC life cycle.

depots are the locations where containers areissued to users and returned from users to poolers.The user leases the containers from the pooler,ships the containers through the supply chain andthe pooler collects the containers after use, inspectsthem and cleans them and keeps them in goodrepair, so they can be used over and over again. Inaddition to high re-use rates, another benefit ofmaintained ownership is that the pooler maintainscontrol of the containers for end-of-life manage-ment. Damaged containers are removed fromservice by the pooler and sent to RPC manufac-turers to be reground and made back into contain-ers. The RPC pooling system is illustrated inFigure 8.

The RPCs in this study are modelled at theaverage weight, lifetime use rate and loss ratereported by the four prominent poolers in theUSA. DRCs are modelled at the reported containerweight for one-piece folded boxes reported by amajor corrugated manufacturer. Additional sce-narios are evaluated for sensitivity analysis, toexamine the effects of reduced backhaul distancefor RPCs, a lower re-use rate and higher loss ratefor RPCs, and container lightweighting for DRCs.

FUNCTIONAL UNIT

In order to ensure a valid basis for comparison forthe container systems studied, a common func-tional unit is essential. For this study, the func-tional unit for each system is shipment of 1000 tons(907 tonnes, or 2 million lb) of each type of produceusing RPCs and DRCs.

SCOPE AND BOUNDARIES

The produce container system models include thefollowing steps:

• Production of virgin polypropylene resin(beginning with raw material extraction) andRPC manufacture.

• Production of corrugated containers withindustry average recycled content (includingcollection and processing of post-consumer cor-rugated boxes and industrial scrap, as well asvirgin inputs to box manufacture).

• Transportation of containers to growers.• Transportation of packed containers from

growers to retail.• Backhauling, washing and re-issue of RPCs.• Recycling and/or disposal of DRCs at end of

life.• Recycling of RPCs retired from service.• Disposal of RPCs lost during use.

The analysis does not include environmentalburdens for growing the produce, neither is anyadditional packaging of produce (e.g. plastic film bags, individual strawberry containers, etc.)included in the analysis. Printing of corrugatedboxes and labelling of RPCs is not included. Theanalysis does not attempt to evaluate differencesin produce damage and spoilage associated withuse of the different types of containers. The analy-sis does not include any analysis of differences inlabour associated with the different containers.

DATA SOURCES

Data on RPC systems, including RPC weights, re-use and loss rates, loading, transportation



RPC POOLING SYSTEM

POOLER COMPANY (Depots)

USER COMPANY(manufacturer/grower)

RPC MANUFACTURER

END USER (retailer/wholesaler)

Offlo

aded

RPC

s backh

auled

New & reissued RPCs

Dam

aged

RPC

s to b

e regro

und an

d

reman

ufactu

red

Product loaded in RPCs

New RPCs

Virginmaterials

Post consumer

Industrial scrap

Figure 8. RPC pooling system.

modes and distances and washing, were providedby companies that manufacture and use RPCs.Weights and loading for DRCs were provided bya DRC producer. DRC weights were validatedusing Corrugated Packaging Alliance (CPA) casestudies on three produce applications that corre-spond to applications analysed in this study.

Production of RPCs was modelled using indus-try average data for the production of polypropy-lene resin and RPC fabrication data provided byRPC producers. Production of DRCs was modelledusing industry average data for the production ofthe various virgin and recycled paperboard inputsto linerboard and medium, production of liner-board and medium, and box fabrication, recoveryand recycling. Paperboard industry statistics were used to model the composition and recycledcontent of linerboard and medium and the itera-tive cycles associated with recovery and recyclingof boxes at end of life.

MODELLING APPROACH

Key data and issues in modelling the containersystems include RPC lifetime trip rates, poolingsystem operation, RPC backhauling, DRC boxweights and end-of-life management of containers.

RPC lifetime trip rates

Data on average RPC lifetime trip rates were pro-vided for this study by RPCC member companiesinvolved in produce shipping, using pooled RPCs.The total number of lifetime trips for an RPC isequal to the number of trips (‘turns’)/year × thenumber of years the container remains in service.The number of turns/year depends on the transportation distances, handling logistics andseasonality of commodities shipped, not on theproperties of the RPC itself.

This study uses the standard LCI basis ofproduct functionality, which in this case is theaverage number of trips an RPC is expected tomake before it is removed from service for wear ordamage, regardless of the number of years it takesto make that number of trips. The lifetime trip rateaffects the modelling of the number of RPCs (and

associated quantity of resin) that must be pro-duced to replace the RPCs ‘used up’ for shipping1000 tons of produce, as described in the followingsection.

RPC pooling operation

An important assumption in the modelling of RPCsystems in this analysis is the assumption that thepooling system is a shared-use pool operating atsteady state. That is, it is assumed that a pool ofRPCs is already in existence and available for anyand all applications (produce or other) that useeach size of RPC. Thus, each produce system ischarged with replacing the number of RPCs ‘usedup’ by shipping that commodity, based on thenumber of shipments in RPCs required to movethe produce divided by the useful lives per RPC,plus replacement of losses of RPCs during use, e.g.due to RPC shipments outside of the controllednetwork or theft.

Although an excess supply of RPCs (‘float’)must be in place throughout the system in order toensure that a sufficient number of RPCs are circu-lating to and from growers and retailers within thetime frame to meet their needs, these RPCs areavailable for any and all uses of each size RPC,rather than designated specifically for a certaintype of produce. However, in some cases, due tothe physical size of the produce, either the large orsmall height RPC may not be an ideal choice.Examples would be shipping hot peppers in thelarge size or melons in the small size RPC.

For a shared-use pool of RPCs, any use of theRPCs for any application is withdrawing RPC usesfrom the pool, rather than individual containers.To calculate the number of RPCs ‘used up’ forshipping 1000 tons of produce, the number of RPCtrips required to ship 1000 tons is divided by thenumber of lifetime trips per RPC and adjusted forthe loss rate to determine the number of RPCs thatmust be produced to replace the RPC uses with-drawn from the pool.

RPC backhauling

The pooling system operates nationwide, enablinggrowers to obtain RPCs from the nearest pooling



location, regardless of where the RPCs were usedprior to arrival at that pooling location. For thisstudy, poolers reported the full backhaul distancefrom produce retailer to pooler back to grower(including routing through a washing facility) spe-cific to each produce application.

In reality, taking into account movements ofRPCs from all uses to all pooling locations, theaverage distance from an end-user to a poolinglocation to a grower is likely considerably shorter,since empty RPCs returned to a pooler may be reis-sued to any user needing that size RPC; they arenot required to be returned to the original growerlocation. However, because it is not possible to esti-mate with certainty where the empty RPCs camefrom to the pooling location, this analysis mod-elled RPC backhauling for each commodity as ifthe RPCs used for each type of produce werereturned to the growers of that type of produce.This would be the maximum backhaul distance.For sensitivity analysis, each commodity is alsoevaluated at 20% reduced backhaul distance toillustrate the probable effect of shared-use pooloperation.

DRC box weights

The weights of DRCs used in the average scenarioare the weights reported by a producer of DRCcontainers and represent the weight of a one-piecefolded box, which is the more prevalent DRC usedin produce applications according to a contact atthe CPA. Bliss boxes are another type of DRC con-tainer that can be used. Bliss boxes provide morestrength per unit weight, but are more expensiveand require that the user purchase equipment toconvert the blank into a box by folding andglueing.

The DRC box weights provided by the DRC pro-ducer were compared to box weights in three casestudies on costs of produce shipping in RPCs andcorrugated published by the CPA. For the threeproduce applications (apples, oranges and grapes),the corrugated box weights used in the CPAstudies were 10–20% higher than the box weightsmodelled in the LCI study for the same produceapplications. Thus, the weights used in the LCIstudy for the ‘average’ DRC scenario alreadyappear to be somewhat conservative for corru-

gated. In addition, to account for potential light-weighting of corrugated containers (e.g. achievedthrough redesign or perhaps use of a bliss box), theconservative scenario in the LCI evaluated DRCsat 10% lightweighting (i.e. 90% of the weightreported by the DRC producer).

End-of-life management

RPCs. Poolers report that RPCs that are removedfrom service are returned to RPC manufacturers,where they are reground and used to produce newRPCs, which will in turn be recycled when they areretired from service. This is considered closed-looprecycling. No burdens for disposal are assigned tothe RPCs that remain in the system and are repeat-edly recycled back into RPCs when they areremoved from service after each multi-trip, multi-year life cycle. Retired RPCs that are not recycledback into RPCs would most likely be recycled intodurable products, such as plastic lumber, indefi-nitely diverting the material from disposal.

Although the material in the RPCs may ulti-mately be recycled many times, this analysis usesa conservative approach in allocating the burdensfor production of the virgin material between theinitial use and the first recycled use, rather thanallocating over a larger number of lifetime cyclesof RPC use and recycling.

All RPCs that are lost from the system duringuse are modelled as entering the municipal solidwaste stream, where they are managed by a com-bination of landfilling and waste-to-energy incin-eration, as described below.

DRCs. The recovery rate for corrugated containersis about 70% overall in the USA;12 however, recov-ery of corrugated containers from grocery stores ismuch higher and is modelled in this study at a rateof 95%. Thus, only 5% of corrugated containers aremodelled as being directly disposed after use. Forthe 95% of boxes that are recovered, burdens forproduction and disposal of the box are allocatedbetween the produce box and secondary uses ofthe recovered fibre, based on the percentages ofopen- and closed-loop recycled content in the box.

For RPCs and DRCs that are disposed, disposalis modelled as 80% landfill and 20% waste-to-



energy incineration.12 An energy credit is assignedto each system based on the weight of containersburned and the higher heating value of the material.

LCI RESULTS

Energy, solid waste and greenhouse gas (GHG)results for each application are summarized inTable 2. For each produce application, Table 2shows results for three RPC scenarios and twoDRC scenarios, representing average containerweights, re-use rates and losses, as well as scenar-ios with reduced RPC backhauling, reduced RPCre-use rate, increased RPC loss rate and DRC light-weighting. Lower re-use rates and higher loss ratesfor RPCs mean that more containers must be manufactured to transport the same quantity ofproduce, more lost containers end up in solidwaste, and there is more material to be recycledfrom retired containers.

DRCs results are shown for container weightsreported by a DRC producer and for 10% light-weighting. For the DRCs, lightweighting reducesmanufacturing requirements, transportation re-quirements and disposal burdens.

Table 2 shows percentage difference compar-isons between RPCs and DRCs for the followingscenarios:

• Average RPC (average re-use and loss rate) at maximum backhaul distance compared toaverage DRC (reported weight for folded box).

• Average RPC (average re-use and loss rate) at20% reduced backhaul distance (‘80% BH’ intable) compared to average DRC.

• Conservative scenario: RPC at 75% of averagere-use rate, twice the average loss rate, maxi-mum backhaul distance compared to DRC with10% lightweighting.

Based on the experience and professional judg-ment of the analysts and supporting statisticalarguments, a minimum percentage difference of10% is used as the threshold for considering a difference in energy results meaningful, while aminimum percentage difference of 25% is used forGHG. Differences that are inconclusive (e.g. belowthese thresholds) are shaded in grey in the table.

Energy results

Energy totals include process energy and trans-portation energy. For RPCs, total energy alsoincludes the energy content of fuel resources (e.g.petroleum and natural gas) used as material feedstocks for the production of plastic resin.

DRCs require more energy than RPCs for cradle-to-production manufacture of containers,transportation of new containers to growers and end-of-life management. RPCs require moreenergy for transportation of packed containersfrom growers to grocery stores. RPCs also requireenergy for backhauling and washing; there are nocorresponding energy requirements for DRCs.

Total energy comparisons are summarized inTable 2 and shown graphically in Figure 9 foraverage scenarios and Figure 10 for conservativescenarios. All comparisons in all scenarios arelower for RPCs, except the conservative scenariocomparisons for apples and strawberries, wherethe differences were inconclusive.

Solid waste results

Total solid wastes include process wastes, processfuel-related wastes, fuel-related wastes for con-tainer transportation and post-consumer wastes.Process wastes are wastes that directly result froma process, such as sludge, unusable byproducts,un-recycled off-spec product or trim scrap, etc.Fuel-related wastes are the wastes associated withthe production and combustion of fuels used forprocess energy or for transportation fuel. Post-consumer wastes are the wastes resulting from theend-of-life management of containers and includeland-filled containers and ash from containers thatare burned.

Comparisons of solid waste by weight are summarized in Table 2 and shown graphically inFigure 11 for average scenarios and Figure 12 forconservative scenarios. RPC systems produce afraction of the solid wastes produced by corre-sponding DRC systems. On average, DRCsproduce 21 times as many tons of solid waste asaverage RPCs with maximum and 20% reducedbackhaul, and 16 times more solid waste thanRPCs in the conservative scenario.





Table 2. Summary of LCI results for all produce container scenarios (all results reported on basisof 1000 tons of produce shipped)

RPCs DRCs Percentage difference*

Avg DRC,Avg with Avg DRC, avg RPC

Fresh produce Avg 80% BH Conserv Avg Conserv avg RPC w/80% BH Conserv

Total energy (million BTU)Apples 853 789 900 1073 966 23 31 7Bell peppers 1121 1040 1188 1818 1637 47 54 32Carrots 531 504 567 981 883 60 64 44Grapes 1080 1010 1141 1920 1729 56 62 41Lettuce (head) 905 839 958 1485 1338 49 56 33Oranges 650 601 692 1241 1117 63 70 47Peaches/nectarines 671 621 707 1284 1156 63 70 48Onions 533 501 566 1075 968 67 73 52Tomatoes 797 736 864 1241 1117 44 51 28Strawberries 1975 1858 2071 2455 2212 22 28 7

Total solid waste (tons)Apples 1.35 1.32 1.60 25.3 22.8 18.8 19.2 14.2Bell peppers 1.99 1.96 2.37 43.2 38.9 21.7 22.1 16.4Carrots 1.04 1.03 1.25 23.4 21.1 22.4 22.7 16.8Grapes 2.15 2.12 2.50 45.5 41.0 21.2 21.4 16.4Lettuce (head) 1.53 1.50 1.82 35.1 31.6 23.0 23.5 17.3Oranges 1.23 1.21 1.47 30.2 27.2 24.5 24.9 18.5Peaches/nectarines 1.25 1.23 1.45 30.5 27.5 24.4 24.8 18.9Onions 1.09 1.07 1.28 25.7 23.1 23.7 24.0 18.2Tomatoes 1.57 1.54 1.84 30.1 27.1 19.2 19.6 14.7Strawberries 4.03 3.98 4.57 55.6 50.1 13.8 14.0 11.0

Total greenhouse gas(tons CO2 equivalents)Apples 62.7 57.5 64.3 67.1 60.5 7 15 −6Bell peppers 81.3 74.7 83.6 113.0 102.0 33 41 20Carrots 37.8 35.6 39.0 61.1 55.1 47 53 34Grapes 78.3 72.6 80.4 120.0 108.0 42 49 29Lettuce (head) 65.9 60.5 67.7 92.8 83.6 34 42 21Oranges 46.6 42.7 48.1 76.9 69.2 49 57 36Peaches/nectarines 49.0 44.9 50.2 80.1 72.2 48 56 36Onions 38.2 35.7 39.4 67.0 60.3 55 61 42Tomatoes 57.5 52.5 59.3 77.0 69.3 29 38 16Strawberries 145.0 135.0 148.0 155.0 140.0 7 14 −6

* Percentage difference = (difference between system results)/(average of system results).Percentage difference is considered inconclusive if <10% for total energy or <25% for GHG.Inconclusive results comparison in the table are shaded grey.Average scenario defined as RPC with average use/loss rates (separate results for maximum and 80% backhaul) and reported weightDRC.Conservative scenario for RPC is use rate at 75% of average and loss rate 2 × the average loss rate. Conservative scenario for DRC is10% lightweighting.

Figure 9. Average scenario energy comparison.



(RPC at avg re-use and loss rate, max. backhaul and 80% backhaul; DRC at reported weight)

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Figure 10. Conservative scenario energy comparison.




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Figure 11. Average scenario solid waste comparison.


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Figure 12. Conservative scenario solid waste comparison.

Emissions results

The discussion here focuses on the high priorityatmospheric issue of greenhouse gas (GHG) emis-sions. The primary three atmospheric emissionsreported in this analysis that contribute to globalwarming are fossil fuel-derived carbon dioxide,methane and nitrous oxide (carbon dioxidereleased from the combustion of wood wastes isconsidered ‘climate neutral’, as it simply returns tothe atmosphere the carbon dioxide that was takenup by the tree during its growing cycle). The globalwarming potential shown in Table 2 and Figure 13for each system is the sum of the weights of fossilcarbon dioxide, methane and nitrous oxide emis-sions multiplied by their 100-year global warmingpotentials.

A summary of GHG results is shown in Table 2.The global warming potentials used in this studyare taken from the International Panel on ClimateChange (IPCC) 2001 report. The 100-year globalwarming potential for the three GHG emissions inthis analysis are: carbon dioxide 1, methane 23, andnitrous oxide 296. The weights of each of these sub-

stances are multiplied by their global warmingpotential and totalled to arrive at the greenhousegas (GHG) totals shown in Table 2.

Figure 13 shows comparative GHG results foraverage scenarios, and Figure 14 shows compara-tive results for conservative scenarios. For theaverage scenarios, total GHG emissions for RPCsare lower than for corresponding DRCs for allapplications except apples and strawberries. Theseare the applications that had the closest energyresults. GHG results generally track closely withfossil fuel consumption, since that is the source of the majority of GHG emissions. For the conser-vative scenario comparisons, RPCs had lowerGHG emissions in half the comparisons, and half were inconclusive. Lower RPC use rates and higher loss rates increase the GHG emissionsfor RPC production, while the container trans-portation GHG that dominate GHG for RPCsremain constant. Lightweighting DRCs reducesGHG burdens for all life cycle stages – productionGHG (which are the dominant source of GHG for DRCs), transportation GHG and end-of-lifeGHG.




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Figure 13. Average scenario GHG comparison.

CONCLUSIONS

For the produce shipping scenarios analysedwithin the defined scope of this study, findingsindicate that, on average across all 10 produceapplications, RPCs require 39% less total energy,produce 95% less total solid waste and generate29% less total greenhouse gas emissions than doDRCs. These findings can be explained below.

One factor dominates the findings. Multipletrips (‘turns’) in an RPC closed operating systemlead to materials efficiencies that create relativelylow environmental burdens that are only partlyoffset by backhaul and cleaning steps. In the DRCsystem a container is manufactured for each trip toretail. Recovery and recycling rates for DRCs arehigh, but the production step (including recycling)introduces a higher level of burdens. In the case ofRPCs and DRCs, multiple re-uses of RPCs result in lower environmental burdens than single-tripDRC containers:

• The more lifetime uses that can be achieved foran RPC, the lower the environmental burdensfor container production that are allocated toeach use of the container. Thus, the success of are-usable container system depends on keepingRPCs in circulation for repeated re-use and recycling. Maximum reductions in containerproduction burdens and disposal burdens areachieved by multiple uses of a containerwithout remanufacturing (i.e. RPC re-use com-pared to DRC recycling).

• Total system energy results. In almost everyproduct application studied, the benefits of theclosed-loop RPC pooling operation more thanoffset the benefits of lighter container weightand a high recycling rate for corrugated con-tainers. As a result, total energy requirementsfor RPCs are lower than corresponding DRCs inall average use scenarios. RPCs also have lowertotal energy requirements than correspondingDRCs in 8/10 alternative scenarios evaluating




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Figure 14. Conservative scenario solid waste comparison.

the effects of lower re-use rates and higher loss rates for RPCs compared to lightweightedDRCs.

• Total system GHG results. GHG results generallytrack closely with fossil fuel consumption, sincethat is the source of the majority of GHG emissions. GHG comparisons for the RPC andDRC average scenarios are lower for RPCs for18/20 average scenarios covering 10 produceapplications.

• Total system solid waste results. RPCs produce lesssolid waste than corresponding DRCs in allproduce applications and scenarios. This is dueto several key factors:(i) The burdens for production of RPCs are

allocated over a (large) number of usefullives.

(ii) RPCs that remain in the closed-looppooling system are recycled when they areremoved from service.

(iii) Losses of RPCs from the closed-loopsystem are small.

(iv) DRCs make only one trip before they arerecycled (requiring repulping and remanu-facture) or disposed.

• EPA has long used the waste management hier-archy of ‘reduce, re-use, recycle’. This LCI con-siders all three techniques: reduction in weightof DRCs, re-use of RPCs and recycling of bothRPCs and DRCs. The results indicate that, forthe produce applications studied, re-use withclosed-loop recycling at end of life is the mostefficient means of reducing not only solid wastebut also energy use and GHG emissions. Reduc-tion in container weight was observed to reducenot only the environmental burdens for con-tainer production and end-of-life management,but also the burdens for container trans-portation (less weight to haul = less fuel consumption). In this study, lightweighting wasevaluated only for DRCs; however, the obser-vations about the benefits of lightweighting also hold true for RPCs or any other type of container.

The results indicate that, for the produce applica-tions studied, re-use with closed-loop recycling atend of life is the most efficient means of reducingnot only solid waste but also energy use and GHGemissions. Reduction in container weight was

observed to reduce not only the environmentalburdens for container production and end-of-lifemanagement, but also the burdens for containertransportation (less weight to haul results in less fuel consumption). Lightweighting was also evaluated for DRCs; however, the benefits of lightweighting would hold good for all containertypes.

REFERENCES

1. ISO 14040.1 Committee Draft. Environmental Man-agement – Life Cycle Assessment – Principles andFramework. 4/15/2004, Ref. no. ISO/TC 207/SC 5N216 Rev. 01:04, 15 April 2004.

2. Tellus. Tellus Packaging Study. Tellus Institute:Boston, MA, 1992.

3. Estimated by Dr Roberta Cook, UC Davis, based onnumerous public sources, including USDA, DOCand the 2002 US Economic Census.

4. www.pma.com [accessed 5 August 2005].5. Clemens R. The expanding US market for fresh

produce. Iowa Agric. Rev. 2004; 10(1), Winter. Centrefor Agricultural and Rural Development: Iowa StateUniversity, Ames, Iowa, USA.

6. The Freedonia Group. Report: Produce Packaging in2008, Study #1828. Cleveland, Ohio, USA, 1 August2004.

7. Corrugated Packaging Alliance news release. Studyshows rising use of corrugated common footprint.Elk Grove Village, IL, USA, 17 May 2005.

8. Society of Environmental Toxicology and Chem-istry. A technical framework for life-cycle assess-ment. Workshop report from the Smugglers Notch, Vermont, USA, 18–23 August 1990. SETAC: Pensacola, FL, USA, 1991.

9. Chonhenchob V, Singh SP. A comparison of corru-gated boxes and re-usable plastic containers for mangodistribution. Packag. Technol. Sci. 2003; 16: 231–237.

10. Chonhenchob V, Singh SP. Packaging performancecomparison for distribution and export of papayafruit. Packag. Technol. Sci. 2005; 18: 125–131.

11. Singh SP, Walker R, Close D. Comparison of return-able paper and plastic corrugated packaging traysfor the USPS. J. Testing Evaluat. 1999; 27(4). ASTM:Vol 27, No 4, 1999.

12. US Environmental Protection Agency. MunicipalSolid Waste in the United States: 2001 Facts and Figures.EPA/530-R-03–011. US EPA: Washington D.C.,October 2003; Table 22, 29.

13. RPCC. Life cycle inventory of re-usable plastic con-tainers and display-ready corrugated containersused for fresh produce. Applications Report pre-pared for Re-usable Plastic Container Coalition(RPCC) by Franklin Associates. RPCC: PrairieVillage, Kansas, USA, 2004.



Documents

Life cycle inventory and analysis of re-usable plastic containers and display-ready corrugated containers used for packaging fresh fruits and vegetables