HomeMy WebLinkAboutEmail - Read Before Packet - 7/1/2014 - Email From Darin Atteberry Re: Agenda Item #22 Re: Bag Ordinance (Sar #26560)1
Debra Unger
From: Debra Unger on behalf of Darin Atteberry
Sent: Tuesday, July 01, 2014 11:36 AM
To: Gerry Horak
Cc: CCSL; Sarah Kane; Susan Gordon; Lucinda Smith; Bruce Hendee; Jeff Mihelich
Subject: Agenda Item #22 RE: bag ordinance (Council SAR #26560)
Attachments: threetypeofgrocerybags.pdf
Gerry,
Please see the response below from Susie Gordon, Senior Environmental Planner, re: your request for staff’s assessment
of the attached report:
~~~~~
Although staff has not had time to read this report (Boudstead Consulting & Associates, 2007) in its entirety yet, we
appreciate the main premise made by its authors that all types of disposable bags have their own environmental
impacts and that it would be inappropriate to simply target disposable plastic bags.
The same perspective was offered by Brendle Group when it prepared a report for Fort Collins (Triple Bottom Line
Evaluation, Plastic Bag Policy Options, 2012). Our consultants evaluated the environmental "footprint" of both plastic
bags and paper bags and recommended that a policy addressing both types of disposables would be warranted. The
ordinance that Council will be reviewing tonight is written to include both plastic and paper single-use bags under the
requirement for a 10-cent charge at groceries.
~~~~~
Staff time: 45 minutes
Debra Unger
Executive Administrative Assistant
City Manager’s Office
(970) 221-6266
Click here to Tell Me About My Service ... I Want to Know!
From: Gerry Horak
Sent: Tuesday, July 01, 2014 6:55 AM
To: CCSL
Subject: FW: bag ordinance (Council SAR #26560)
Darin
Interesting study attached. Has staff reviewed this report? Please provide an assessment prior to the meeting tonight.
Thanks
Gerry
2
From: chris damir [240christian@gmail.com]
Sent: Monday, June 30, 2014 11:17 PM
To: City Leaders
Subject: bag ordinance
Dear City Leaders,
I ask that you reject the proposed bag ordinance. Refer to the attached report and conclusions quoted below.
Banning single use grocery bags was concluded may have deleterious environmental effects.
"When compared to 30% recycled fiber paper bags, polyethylene grocery bags use less energy in terms of fuels
for manufacturing, less oil, and less potable water. In addition, polyethylene plastic grocery bags emit fewer
global warming gases, less acid rain emissions, and less solid wastes. The same trend exists when comparing
the typical polyethylene grocery bag to grocery bags made with compostable plastic resins—traditional plastic
grocery bags use less energy in terms of fuels for manufacturing, less oil, and less potable water, and emit fewer
global warming gases, less acid rain emissions, and less solid wastes."
"The study results support the conclusion that any decision to ban traditional polyethylene plastic grocery bags
in favor of bags made from alternative materials (compostable plastic or recycled paper) will be
counterproductive and result in a significant increase in environmental impacts across a number of categories
from global warming effects to the use of precious potable water resources"
Quoted from:
Life Cycle Assessment for Three Types of Grocery Bags - Recyclable Plastic; Compostable,
Biodegradable Plastic; and Recycled, Recyclable aper (Boustead Consulting & Associates,
September, 2007)
BOUSTEAD CONSULTING & ASSOCIATES
“FINAL REPORT”
Life Cycle Assessment for Three Types of Grocery
Bags - Recyclable Plastic; Compostable,
Biodegradable Plastic; and Recycled, Recyclable
Paper
Prepared for the Progressive Bag Alliance
Chet Chaffee and Bernard R. Yaros
Boustead Consulting & Associates Ltd.
BCAL 2 LCA Grocery Bags
TABLE OF CONTENTS
TABLE OF CONTENTS............................................................................................................................. 2
EXECUTIVE SUMMARY.......................................................................................................................... 3
Introduction .................................................................................................................................................. 5
Study Goal..................................................................................................................................................... 6
Scope.............................................................................................................................................................. 6
Methodological Approach............................................................................................................................ 9
Calculations of LCAs ................................................................................................................................. 9
Using LCA data …BCAL scientific viewpoint........................................................................................ 10
Data Sources and Data Quality................................................................................................................. 11
Data reporting............................................................................................................................................. 11
LCA Results Tables.................................................................................................................................... 13
RECYCLABLE PAPER BAG SYSTEM ................................................................................................ 13
RECYCLABLE PLASTIC BAG SYSTEM............................................................................................. 18
THE COMPOSTABLE PLASTIC BAG SYSTEM................................................................................. 30
Final Disposal Solid Waste Options: Recycling, Combustion with Energy Recovery, Landfill and
Composting ................................................................................................................................................. 41
Recycling.................................................................................................................................................. 41
Solid Waste Combustion With Energy Recovery..................................................................................... 41
Solid Waste to Landfill............................................................................................................................. 42
Scenario 1 for Paper Bags ........................................................................................................................ 43
Scenario 2 for Paper Bags ........................................................................................................................ 43
Solid Waste Composting .......................................................................................................................... 44
LCA Calculations of Environmental Impacts.......................................................................................... 44
GLOBAL WARMING............................................................................................................................. 45
STRATOSPHERIC OZONE DEPLETION............................................................................................. 50
ACID RAIN ............................................................................................................................................. 50
MUNICIPAL SOLID WASTE ................................................................................................................ 51
CONSERVATION OF FOSSIL FUELS.................................................................................................. 52
LOCAL & REGIONAL GRID ELECTRICITY USE.............................................................................. 53
WATER USE & PUBLIC SUPPLY ........................................................................................................ 54
Summary and Conclusions ........................................................................................................................ 55
Literature References................................................................................................................................. 61
Referencs Regarding the Boustead Model ............................................................................................... 62
Appendix 1 – Peer Review ......................................................................................................................... 63
BCAL 3 LCA Grocery Bags
EXECUTIVE SUMMARY
In the pursuit to eliminate all that is not green, plastic seems to be a natural target. Its
widespread use in products and packaging, some say, has contributed to environmental
conditions ranging from increased pollution to overloaded landfills to the country’s
dependence on oil. In response, some cities have adopted legislation that bans plastic
grocery bags made from polyethylene in favor of bags made from materials such as cloth,
compostable plastics, or paper.
But will switching from grocery bags made from polyethylene to bags made from some
other material guarantee the elimination of unfavorable environmental conditions? We
know that every product—through its production, use, and disposal—has an
environmental impact. This is due to the use of raw materials and energy during the
production process and the emission of air pollutants, water effluents, and solid wastes.
More specifically, are grocery bags made other materials such as paper or compostable
plastics really better for the environment than traditional plastic grocery bags? Currently,
there is no conclusive evidence supporting the argument that banning single use plastic
bags in favor of paper bags will reduce litter, decrease the country’s dependence on oil,
or lower the quantities of solid waste going to landfills. In addition, there is limited
information on the environmental attributes of compostable plastics and how they fare
against traditional plastic grocery bags or paper bags.
To help inform the debate about the environmental impacts of grocery bags, the
Progressive Bag Alliance contracted with Boustead Consulting & Associates (BCAL) to
conduct a life cycle assessment (LCA) on three types of grocery bags: a traditional
grocery bag made from polyethylene, a grocery bag made from compostable plastics (a
blend of 65% EcoFlex, 10% polylactic acid or PLA, and 25% calcium carbonate), and a
paper grocery bag made using at least 30% recycled fibers. The life cycle assessment
factored in every step of the manufacturing, distribution, and disposal stages of these
grocery bags. It was recognized that a single traditional plastic grocery bag may not have
the same carrying capacity as a paper bag, so to examine the effect of carrying capacity,
calculations were performed both on a 1:1 basis as well as an adjusted basis (1:1.5) paper
to plastic.
BCAL compiled life cycle data on the manufacture of polyethylene plastic bags and
compostable plastic bags from the Progressive Bag Alliance. In addition, BCAL
information on the compostable plastic resin EcoFlex from the resin manufacturer BASF.
BCAL completed the data sets necessary for conducting life cycle assessments using
information extracted from The Boustead Model and Database as well as the technical
literature. BCAL used the Boustead Model for LCA to calculate the life cycle of each
grocery bag, producing results on energy use, raw material use, water use, air emissions,
water effluents, and solid wastes.
BCAL 4 LCA Grocery Bags
The results show that single use plastic bags made from polyethylene have many
advantages over both compostable plastic bags made from EcoFlex and paper bags made
with a minimum of 30% recycled fiber.
Impact Summary of Various Bag Types
(Carrying Capacity Equivalent to 1000 Paper Bags)
Paper
(30% Recycled
Fiber)
Compostable
Plastic
Polyethylene
Total Enegy Usage (MJ) 2622 2070 763
Fossil Fuel Use (kg) 23.2 41.5 14.9
Municipal Solid Waste (kg) 33.9 19.2 7.0
Greenhouse Gas Emissions
(CO2 Equiv. Tons) 0.08 0.18 0.04
Fresh Water Usage (Gal) 1004 1017 58
less
The findings of this study were peer reviewed by an independent third party with
significant experience in life cycle assessments to ensure that the results are reliable and
repeatable. The results support the conclusion that any decision to ban traditional
polyethylene plastic grocery bags in favor of bags made from alternative materials
(compostable plastic or recycled paper) will result in a significant increase in
environmental impacts across a number of categories from global warming effects to the
use of precious potable water resources. As a result, consumers and legislators should re-
evaluate banning traditional plastic grocery bags, as the unintended consequences can be
significant and long-lasting.
When compared to 30% recycled fiber paper bags, polyethylene grocery bags use
energy in terms of fuels for manufacturing, less oil, and less potable water. In addition,
polyethylene plastic grocery bags emit fewer global warming gases, less acid rain
emissions, and less solid wastes. The same trend exists when comparing the typical
polyethylene grocery bag to grocery bags made with compostable plastic resins—
traditional plastic grocery bags use less energy in terms of fuels for manufacturing, less
oil, and less potable water, and emit fewer global warming gases, less acid rain
emissions, and less solid wastes.
BCAL 5 LCA Grocery Bags
Introduction
In the national effort to go green, several states, counties, and cities are turning their
attention to plastic grocery bags made from polyethylene because of the perception that
plastic bags contribute to local and global litter problems that affect marine life, occupy
the much needed landfill space with solid waste, and increase U.S. dependence on oil.
To address these environmental issues, and perhaps in seeking to follow the example of
other countries such as Australia and Ireland, legislators in several cities across the
United States have proposed or have already passed ordinances banning single use
polyethylene plastic grocery bags in favor of bags made from alternative materials such
as cloth, paper, or compostable plastic. Legislators state that they believe that these new
laws and proposals will reduce litter, reduce the use of fossil fuels, and improve the
overall environmental impacts associated with packaging used to transport groceries.
Before we examine whether plastic bags cause more environmental impacts than the
alternative materials proposed, we should first consider the most commonly proposed
alternatives, which tend to include: cloth bags, compostable plastic bags, and paper bags.
Reusable cloth bags may be the preferred alternative, but in reality, there is no evidence
that most, or even a majority of, customers will reliably bring reusable bags each time
they go shopping.
Compostable plastic bags, although available, are in short supply as the technology still is
new, and therefore cannot currently meet market demand. So it appears that the proposed
laws banning plastic grocery bags may simply cause a shift from plastic bags to the only
alternative that can immediately supply the demand—paper bags.
Therefore, is legislation that mandates one packaging material over another
environmentally responsible given that all materials, products, and packaging have
environmental impacts? The issue is whether the chosen alternatives will reduce one or
several of the identified environmental impacts, and whether there are any trade-offs
resulting in other, potentially worse, environmental impacts.
To help inform the debate on the environmental impacts of grocery bags, and identify the
types and magnitudes of environmental impacts associated with each type of bag, the
Progressive Bag Alliance contracted Boustead Consulting & Associates (BCAL) to
conduct a life cycle assessment (LCA) on single use plastic bags as well as the two most
commonly proposed alternatives: the recyclable paper bag made in part from recycled
fiber and the compostable plastic bag.
Life cycle assessment is the method being used in this study because it provides a
systems approach to examining environmental factors. By using a systems approach to
analyzing environmental impacts, one can examine all aspects of the system used to
produce, use, and dispose of a product. This is known as examining a product from
cradle (the extraction of raw materials necessary for producing a product) to grave (final
BCAL 6 LCA Grocery Bags
disposal of the product). LCA has been practiced since the early 1970s, and standardized
through several organizations including SETAC (Society of Environmental Toxicology
and Chemistry) and ISO (International Standards Organization). LCA studies examine
the inputs (resources and energy) and outputs (air emissions, water effluents, and solid
wastes) of each system and thus identifies and quantifies the effects of each system,
providing insights into potential environmental impacts at local, regional, and global
levels.
To compile all the information and make the calculations, BCAL uses the Boustead
Model and Database. The Boustead Model and Database is an LCA software model with
a database built over the past 25 years, containing a wide variety of data relevant to the
proposed study. Dr. Boustead has pioneered the use of life-cycle methods and has
conducted hundreds of studies, including those for the plastics industry; which have been
reviewed by US and European industry as well as life-cycle practitioners.
Study Goal
According to ISO 14040, the first steps in a life cycle project are defining the goal and
scope of the project to ensure that the final results meet the specific needs of the user.
The purpose of this study is to inform the debate on the environmental impacts of grocery
bags, and identify the types and magnitudes of environmental impacts associated with
each type of bag. In addition, the study results aim to inform the reader about the
potential for any environmental trade-offs in switching from grocery bags made from one
material, plastic, to another, paper.
The life cycle assessment was conducted on three types of grocery bags: a traditional
grocery bag made from polyethylene, a grocery bag made from compostable plastics (a
blend of 65% EcoFlex, 10% polylactic acid or PLA, and 25% calcium carbonate), and a
paper grocery bag made using at least 30% recycled fibers. It is important to note that the
study looked at only one type of degradable plastic used in making grocery bags, which is
the bag being studied by members of the Progressive Bag Alliance. Since this is only one
of a number of potential blends of plastic that are marketed as degradable or
compostable, the results of this study cannot be used to imply that all compostable bags
have the same environmental profile.
Scope
The scope of the study is a cradle to grave life cycle assessment which begins with the
extraction of all raw materials used in each of the bags through to the ultimate disposal of
the bags after consumer use, including all the transport associated with the delivery of
raw materials and the shipping and disposal of final product.
The function of the product system under study is the consumer use and disposal of a
grocery bag. The functional unit is the capacity of the grocery bag to carry consumer
purchases. A 1/6 BBL (Barrel) size bag was selected for all three bags in this study
because that is the commonly used bag in grocery stores. Although the bags are of equal
size, previous studies (Franklin, 1990) pointed out that the use of plastic bags in grocery
BCAL 7 LCA Grocery Bags
stores was not equal to the use of paper bags. According to Franklin (1990), bagging
behavior showed that plastic to paper use ranged from 1:1 all the way to 3:1, depending
on the situation. In contrast, data collected by the Progressive Bag Alliance shows that
plastic and paper bags are somewhat equal in use once the baggers have been properly
trained. In this study BCAL used both 1:1 and 1.5:1 plastic to paper ratios, allowing for
the possibility that it still takes more plastic bags to carry the same amount of groceries as
a paper bag. The 1.5:1 ratio equates to 1500 plastic bags for every 1000 paper bags.
BCAL prepared LCA’s for the three types of grocery bags. The data requirements for
BCAL and for the Progressive Bag Alliance are outlined below.
1. Recyclable Paper Bag LCA………The following operations are to be included
in the analysis: To start, BCAL provided data on the extraction of fuels and
feedstocks from the earth, including tree growing, harvesting, and transport of
all materials. BCAL added process operations in an integrated unbleached kraft
pulp & paper mill including recycling facility for old corrugated containers;
paper converting into bags; closed-loop recycling of converting bag waste;
packaging and transport to distribution and grocery stores; consumer use; and
final disposal. Data for most of the above operations in one form or another are
in the Boustead Model and Database. Weyerhaeuser reported that its unbleached
kraft grocery bag contains about 30% post consumer recycled content and the
use of water-based inks1. Therefore, in this study BCAL used 30% recycled
material. This is also somewhat reflective of current legislation where minimum
recycled content in paper bags is required (see Oakland City Council Ordinance
requiring 40% recycled material). In the operations leading to final disposal
BCAL estimated data for curbside collection and generation and recovery of
materials in MSW from government agencies and EPA data, which for 2005
showed paper bag recycling at 21%, paper bag MSW for combustion with
energy recovery at 13.6%, resulting in 65.4% to landfill2. The following final
disposal options will also be considered: composting and two landfill scenarios.
2. Recyclable Plastic Bag LCA………The following operations are to be included
in the analysis: The extraction of fuels and feedstocks from the earth; transport
of materials; all process and materials operations in the production of high and
low density polyethylene resin3; converting PE resin into bags; packaging and
transport of bags to distribution centers and grocery stores; consumer use; and
final disposal. In the operations leading to final disposal, BCAL estimated data
for curbside collection and generation and recovery of materials in MSW from
government agencies and EPA data, which for 2005 showed plastic bag
recycling at 5.2 %, plastic bag MSW for combustion with energy recovery at
13.6%, resulting in 81.2% to landfill2. The following final disposal options will
also consider two landfill scenarios.
Data for the converting operation was collected specifically from a member of
the Progressive Bag Alliance that makes only plastic grocery bags. The data
obtained, represents the entire annual production for 2006. All waste is
BCAL 8 LCA Grocery Bags
reprocessed on site, so that is how the calculations were conducted. All inks are
water-based, and the formulas provided. The production and supply of all PE
resin is based on materials produced and transported from a Houston based
supplier. The corrugated boxes were included as made from recycled material to
reflect the fact that the supplier to the PBA member reported using between
30% and 40% post consumer recycled fiber1.
3. Degradable Plastic Bag (EcoFlex and PLA mix) LCA………The following
operations are to be included in the analysis: The extraction of fuels and
feedstocks from the earth; production and transport of materials for all process
and materials operations in the production of polylactide resin; EcoFlex from
BASF (data provided by BASF)4; and calcium carbonate, converting the
EcoFlex/PLA resin mixture into bags; packaging and transport of bags to
distribution centers and grocery stores; consumer use; and final disposal. Again,
most of the above operations are contained in the Boustead Model and
Database. The production data for PLA was obtained from NatureWorks5 and
the data for EcoFlex was obtained from BASF4. Both NatureWorks and BASF
use the Boustead Model for their LCA calculations, so the data BCAL requested
and received was compatible with other data used in the study. In addition,
BCAL sent its calculated results to BASF for confirmation that the data and the
calculations on bags made from the EcoFlex compostable resin was accurate.
BASF engineers confirmed that BCAL’s use of the data and the calculated
results were appropriate. In the operations leading to final disposal, BCAL
estimated data for curbside collection and generation and recovery of materials
in MSW from government agencies and EPA data3, which for 2005 showed
plastic bag recycling at 5.2 %, plastic bag MSW for combustion with energy
recovery at 13.6%, resulting in 81.2% to landfill2. The following final disposal
options will be also be considered: composting and two landfill scenarios.
Data for the converting operation of the EcoFlex/PLA resin mixture was
collected at the same PBA member facility during a two-week period at the end
of May 2007. The production and supply of the PLA polymer is from Blair, NE.
The production and supply of Ecoflex polymer is from a BASF plant in
Germany. The trial operations at the PBA member’s facility indicate that the
overall energy required to produce a kilogram of EcoFlex/PLA bags may be
lower than the overall energy required to produce a kilogram of PE bags, based
on preliminary in-line electrical measurements conducted by plant engineers.
However, these results still are preliminary, and need to be confirmed when full
scale operations are implemented. As a result, this study will assume that the
overall energy required to produce a kilogram of EcoFlex/PLA bags is the same
as the overall energy required to produce a kilogram of PE bags. The plastic bag
recycling at 5.2 %, will be assumed to go to composting. The inherent energy of
the degradable bags has been estimated from NatureWorks and BASF sources.
BCAL 9 LCA Grocery Bags
The following are some detailed specifications for the LCA study:
Recyclable Plastic Degradable Plastic Recyclable Paper
Size/type 1/6 BBL 1/6 BBL 1/6 BBL
Length (inches) 21.625 22.375 17
Width (inches) 12 11.5 12
Gusset (inches) 7.25 7.25 6.75
Gauge (Mil) 0.51 0.75 20 lb /1000 sq ft
Film Color White White Kraft
Material HDPE (film grade
blend)
Degradable Film
Compound
(EcoFlex/PLA mix)
Unbleached Kraft
Paper
Jog Test (strokes) 45 20 n/a
Tensile Strength (lb) 50 35 n/a
Weight per 1000
bags in lbs
13.15 (5.78 kg) 34.71 (15.78 kg) 114 (51.82 kg)
Human energy and capital equipment will not be included in the LCA; detailed
arguments for this decision are presented in the proposal appendix.
Methodological Approach
BCAL followed the sound scientific practices as described in ISO 14040, 14041, and
14042 to produce the project results. BCAL is well versed in the requirements of the ISO
standards as Dr. Ian Boustead has and continues to be one of the leading experts
participating in the formation of the ISO standards. The procedures outlined below are
consistent with the ISO standards and reflect BCAL’s approach to this project.
Calculations of LCAs
The Boustead database contains over 6000 unit operations on the processes required to
extract raw materials from the earth, process those materials into useable form, and
manufacture products. These operations provide data on energy requirements, emissions
and wastes.
The “Boustead Model” software was used to calculate the consumption of energy, fuels,
and raw materials, and generation of solid, liquid, and gaseous wastes starting from the
extraction of primary raw materials. The model consists of a calculating engine that was
developed 25 years ago and has been updated regularly based on client needs and
technical innovations. One important consequence of the modeling is that a mass balance
for the entries system is calculated. Therefore, the resource use and the solid waste
production are automatically calculated.
Fuel producing industry data are available for all of the OECD countries and some non-
OECD countries. The United States and Canada are further analyzed by region; the US is
BCAL 10 LCA Grocery Bags
divided into 9 regions and Canada is sub-divided in 5 regions, corresponding to the
Electric Reliability Council. For both the US and Canada, there also is a national average.
Since the whole of the Model database can be switched from one country to another, any
operation with data from outside the US can be adjusted for energy from non-US energy
inputs to “USA adjusted” energy inputs. Assuming that the technology is the same, or
very similar, this allows BCAL to fill any data gaps with data from similar operations in
non-US locations.
Another important aspect of calculating LCAs is the use of allocation procedures when
differentiating the use of energy and raw materials associated with individual products
within a single system. In many cases, allocation methods that defy or at the very least,
ignore sound scientific practice (such as economics) have been used when they benefit
clients. These types of errors or biases are important to avoid as they are easily
discovered by peer reviewers or technical experts seeking to use the results in subsequent
studies (such as building applications), which unfortunately can cause the rest of the work
to be discounted due to unreliability. BCAL has considerable experience in this arena
having published several technical papers on the appropriate allocation principles in the
plastics industry. Utilizing sound scientific principles and objective measures to the
greatest extent possible, BCAL has been able to avoid most problems associated with
allocation decisions and produce accurate and reliable LCA data for a wide variety of
plastics. Proof of this is the widespread use of PlasticsEurope data (produced by Boustead
Consulting) in almost every life cycle database available worldwide as well as in life
cycle studies in numerous product and building applications.
Calculated data are readily aggregated and used to produce the final LCA data set which
includes the impact assessment step of LCA. These resulting data sets address specific
environmental problems.
Using LCA data.…BCAL scientific viewpoint
Life cycle assessment modeling allows an examination of specific problems as well as
comparisons between systems to determine if there are any serious trade-offs between
systems. In every system there are multiple environmental parameters to be addressed
scaling from global to local issues. No single solution is likely to address all of the issues
simultaneously. More importantly, whenever choices are being made to alter a system or
to utilize an alternative system, there are potential trade-offs. Understanding those trade-
offs is important when trying to identify the best possible environmental solution.
Hopefully, decisions to implement a change to an existing system will consider the
potential trade-offs and compromises. While LCA can identify the environmental factors
and trade-offs, choosing the solution that is optimal is often subjective and political.
Science can only help by providing good quality data from which decisions can be made.
The strength of the proposed LCA assessment system is that these unwanted side effects
can be identified and quantified.
A life cycle assessment can:
1. Quantify those parameters likely to be responsible for environmental effects (the
inventory component of life cycle analysis).
BCAL 11 LCA Grocery Bags
2. Identify which parameters are likely to contribute to a specific environmental
problem (characterization or interpretation phase of impact assessment). An
example would be identifying that carbon dioxide (CO2), methane (CH4), and
nitrous oxide (N2O) are greenhouse gases.
3. Aggregate the parameters relating to a specific problem (the valuation or
interpretation phase of impact assessment). An example would be producing
carbon dioxide equivalents for the components of greenhouse gases.
LCA derived data provide a compilation of information from which the user can address
specific problems, while also examining potential trade-offs. For example, if interested in
addressing specific conservation issues such as the conservation of fossil fuels, the user
would examine the mass and energy data for only coal, oil, and natural gas; and ignore
the other information. If the user would like to examine the potential impacts the grocery
bag system has on global warming, acid rain, and municipal solid waste one can address
these issues both individually and cooperatively by examining the specific parameters
which are likely to contribute to each. In so doing, the user can strive to achieve the
optimum reduction in each parameter because of a better understanding of how these
parameters change in association with the grocery bag system as a whole and each other
individually.
Data Sources and Data Quality
As noted above, data sources included published reports on similar materials, technical
publications dealing with manufacturing processes, and data incorporated into the
Boustead Model and Database, most of which has been generated through 30 years of
industrial studies on a wide range of products and processes.
ISO standards 14040, 14041, and 14042 each discuss aspects of data quality as it pertains
to life cycle assessments. In general, data quality can be evaluated using expert judgment,
statistics, or sensitivity analysis. In LCA studies, much of the data do not lend itself to
statistical analyses as the data are not collected randomly or as groups of data for each
input variable. Instead, most LCA data are collected as single point estimates (i.e., fuel
input, electricity input, product output, waste output, etc). Single point estimates are
therefore only able to be evaluated through either expert judgment or sensitivity analysis.
Since the reliability of data inevitably depends upon the quality of the information
supplied by individual operators, BCAL used its expert judgment to carry out a number
of elementary checks on quality. BCAL checked mass and energy balances to ensure that
the data did not violate any of the basic physical laws. In addition, BCAL checked data
from each source against data from other sources in the Boustead Model and Database to
determine if any data fell outside the normal range for similar products or processes.
Data reporting
To enhance the comparability and understanding of the results of this study, the detailed
LCA results are presented in the same presentation format that was used for the series of
eco-profile reports published by the Association of Plastics Manufacturers in Europe
BCAL 12 LCA Grocery Bags
(APME). A set of eight tables, each describing some aspect of the behavior of the system,
shows the results of the study. Five tables in the data set are useful in conservation
arguments and three tables are indications of the potential pollution effects of the system.
The performance of the grocery bag systems is described by quantifying the inputs and
outputs to the system. The calculation of input energy and raw materials quantifies the
demand for primary inputs to the system and these parameters are important in
conservation arguments because they are a measure of the resources that must be
extracted from the earth in order to support the system.
Calculation of the outputs is an indication of the potential pollution effects of the system.
Note that the analysis is concerned with quantifying the emissions; it does not make any
judgments about deleterious or beneficial properties.
The inputs and outputs depend on the definition of the system—they are interrelated.
Therefore, any changes to the components of the system means that the inputs and
outputs will likely change as well. One common misconception is that it is possible to
change a single input or output while leaving all other parameters unchanged. In fact, the
reverse is true; because a new system has been defined by changing one input or output,
all of the inputs and outputs are expected to change. If they happen to remain the same, it
is a coincidence. This again illustrates the fact that common perceptions about
environmental gains from simple changes may be misleading at best, and detrimental to
the environment at worst.
Increasingly there is a demand to have the results of eco-profile analyses broken down
into a number of categories, identifying the type of operation that gives rise to them. The
five categories that have been identified are:
1. Fuel production 4. Biomass
2. Fuel use 5. Process
3. Transport
Fuel production operations are defined as those processing operations which result in the
delivery of fuel, or energy; to a final consumer whether domestic or industrial. For such
operations all inputs, with the sole exception of transport, are included as part of the fuel
production function.
Fuel use is defined as the use of energy delivered by the fuel producing industries. Thus
fuel used to generate steam at a production plant and electricity used in electrolysis would
be treated as fuel use operations. Only the fuel used in transport is kept separate.
Transport operations are easily identified and so the direct energy consumption of
transport and its associated emissions are always separated.
Biomass refers to the inputs and outputs associated with the use of biological materials
such as wood or wood fiber.
BCAL 13 LCA Grocery Bags
LCA RESULTS TABLES
RECYCLABLE PAPER BAG SYSTEM
The results of the LCA for the recyclable paper bag system are presented below, each
describing some aspect of the behavior of the systems examined. In all cases, the
following tables refer to the gross or cumulative totals when all operations are traced
back to the extraction of raw materials from the earth and are based on the consumer use
and collection of 1000 bags. The subsequent disposal operations of recycling,
composting, incineration with energy recovery and landfill are not included in these
results tables and will be discussed separately.
Table 1. Gross energy (in MJ), required for the recyclable PAPER bag LCA. Based on
consumer use & collection of 1000 bags. Totals may not agree because of rounding.
Fuel type Fuel prod’n &
delivery
Energy content
of fuel
Transport
energy
Feedstock
energy
Total energy
Electricity 461 185 3 0 649
Oil 17 143 30 1 191
Other 15 777 1 990 1783
Total 493 1105 34 991 2622
BCAL 14 LCA Grocery Bags
Table 2. Gross primary fossil fuels and feedstocks, expressed as energy (in MJ ),
required for the recyclable PAPER bag LCA. Based on consumer use & collection of
1000 bags. Totals may not agree because of rounding.
Fuel prod’n Fuel use Transport Feedstock Total
Coal 229 94 1 0 324
Oil 23 150 33 1 207
Gas 113 278 0 0 391
Hydro 15 6 0 - 21
Nuclear 90 36 0 - 127
Lignite 0 0 0 - 0
Wood 0 533 0 988 1521
Sulfur 0 0 0 2 2
Hydrogen 0 0 0 0 0
Biomass (solid) 18 7 0 0 24
Recovered energy 0 -1 0 - -1
Geothermal 0 0 0 - 0
Unspecified 0 0 0 - 0
Solar 0 0 0 - 0
Biomass (liqd/gas) 1 0 0 - 1
Industrial waste 1 0 0 - 1
Municipal Waste 3 1 0 - 4
Wind 0 0 0 - 0
Totals 493 1105 34 991 2622
Table 3. Gross primary fossil fuels and feedstocks, expressed as mass (in milligrams),
the recyclable PAPER bag LCA. Based on consumer use & collection of 1000 bags.
Totals may not agree because of rounding.
Crude oil…………….. 4,591,000
Gas/condensate……… 7,432,000
Coal…………………. 11,210,000
Metallurgical coal…... 25,900
Lignite ……………. 79
Peat …………………. 444
Wood (50% water)….. 274,000,000
Biomass (incl. water)… 2,880,000
Table 4. Gross water resources (in milligrams) required for the recyclable PAPER bag
LCA. Based on consumer use & collection of 1000 bags. Totals may not agree because of
rounding.
Source Use in process Use in cooling Totals
Public supply 3,895,000,000 - 3,895,000,000
River/canal 5,260 1,920 7,190
Sea 8,490 1,092,000 1,100,000
Unspecified 14,600,000 2,910,000 17,500,000
Well 200 50 250
Totals 3,909,000,000 4,000,000 3,913,000,000
Note: total cooling water reported in recirculating systems = 404.
BCAL 15 LCA Grocery Bags
Table 5. Gross other raw materials (in milligrams required for the recyclable PAPER bag
LCA. Based on consumer use & collection of 1000 bags. Totals may not agree because of
rounding.
Raw material Input in mg
Air 4,080,000
Animal matter 0
Barites 211
Bauxite 469
Bentonite 51
Biomass (including water) 0
Calcium sulphate (CaSO4) 0
Chalk (CaCO3) 0
Clay 46,300
Cr 31
Cu 0
Dolomite 792
Fe 64,800
Feldspar 0
Ferromanganese 59
Fluorspar 9
Granite 0
Gravel 239
Hg 0
Limestone (CaCO3) 385,000
Mg 0
N2 6,050
Ni 0
O2 1,180
Olivine 608
Pb 395
Phosphate as P205 147,000
Potassium chloride (KCl) 7
Quartz (SiO2) 0
Rutile 0
S (bonded) 1
S (elemental) 233,000
Sand (SiO2) 101,600
Shale 1
Sodium chloride (NaCl) 712,000
Sodium nitrate (NaNO3) 0
Talc 0
Unspecified 0
Zn 14
BCAL 16 LCA Grocery Bags
Table 6. Gross air emissions (in milligrams) resulting from the recyclable PAPER bag
LCA. Based on consumer use & collection of 1000 bags. Totals may not agree because of
rounding.
Air emissions/mg Fuel prod’n Fuel use Transport Process Biomass Fugitive Total
Dust 32,900 4,440 1,930 89,000 - - 128,000
CO 59,500 16,300 23,000 21,900 - - 121,000
CO2 43,100,000 22,600,000 2,330,000 1,066,000 -63,600,000 - 5,507,000
SOX 168,000 166,000 6,030 239,000 - - 579,000
NOX 151,000 86,400 26,500 600 - - 264,000
N2O <1 <1 - - - <1
Hydrocarbons 49,000 16,000 7,300 60 - 72,300
Methane 266,000 16,200 10 3,500 - 286,000
H2S <1 - <1 2,750 - - 2,750
Aromatic HC 6 - 98 1 - - 105
HCl 6,440 42 4 622 - 7,110
Cl2 <1 - <1 <1 - <1
HF 242 2 <1 <1 - 244
Lead <1 <1 <1 <1 - <1
Metals 25 105 - <1 - 131
F2 <1 - <1 <1 - <1
Mercaptans <1 <1 <1 802 - - 802
H2 124 <1 <1 91 - - 215
Organo-chlorine <1 - <1 <1 - <1
Other organics <1 <1 <1 <1 - 1
Aldehydes (CHO) - - - 13 - 13
Hydrogen (H2) 152 - - 3,130 - 3,280
NMVOC 2 - <1 <1 - 2
Table 6B. Carbon dioxide equivalents corresponding to the gross air emissions (in
milligrams) resulting from the recyclable PAPER bag LCA. Based on consumer use &
collection of 1000 bags. Totals may not agree because of rounding.
Type/mg Fuel prod’n Fuel use Transport Process Biomass Total
20 year equiv 59,850,000 23,690,000 2,400,000 1,330,000 -63,560,000 23,710,000
100 year equiv 49,460,000 23,060,000 2,400,000 1,190,000 -63,560,000 12,550,000
500 year equiv 45,200,000 22,800,000 2,400,000 1,130,000 -63,560,000 7,970,000
BCAL 17 LCA Grocery Bags
Table 7. Gross water emissions (in milligrams), resulting from the recyclable PAPER
bag LCA. Based on consumer use & collection of 1000 bags.. Totals may not agree
because of rounding.
Fuel prod’n Fuel use Transport Process Total
COD 55 - 35 396,000 396,000
BOD 14 - <1 75,000 75,000
Acid (H+) 11 - <1 1 13
Al+compounds as Al <1 - <1 <1 <1
Ammonium compounds as NH4 19 - 2 <1 22
AOX <1 - <1 <1 <1
As+compounds as As - - <1 <1 <1
BrO3-- <1 - <1 <1 <1
Ca+compounds as Ca <1 - <1 19 20
Cd+compounds as Cd - - <1 - <1
Cl- 25 - 35 10,400 10,400
ClO3-- <1 - <1 97 97
CN- <1 - <1 <1 <1
CO3-- - - 3 30 34
Cr+compounds as Cr <1 - <1 <1 <1
Cu+compounds as Cu <1 - <1 <1 <1
Detergent/oil <1 - 2 3 6
Dichloroethane (DCE) <1 - <1 <1 <1
Dioxin/furan as Teq - - <1 - <1
Dissolved chlorine <1 - <1 <1 <1
Dissolved organics (non-HC) 23 - <1 <1 23
Dissolved solids not specified 1 - 9 3,700 3,710
F- <1 - <1 <1 <1
Fe+compounds as Fe <1 - 2 <1 3
Hg+compounds as Hg <1 - <1 <1 <1
Hydrocarbons not specified <1 <1 2 <1 3
K+compounds as K <1 - <1 <1 <1
Metals not specified elsewhere 3 - <1 3,060 3,060
Mg+compounds as Mg <1 - <1 <1 <1
Mn+compounds as Mn - - <1 <1 <1
Na+compounds as Na 10 - 22 7,510 7,540
Ni+compounds as Ni <1 - <1 <1 <1
NO3- 1 - <1 76 78
Organo-chlorine not specified <1 - <1 6 6
Organo-tin as Sn - - <1 - <1
Other nitrogen as N 3 - <1 7,950 7,950
Other organics not specified <1 - <1 <1 <1
P+compounds as P <1 - <1 879 880
Pb+compounds as PB <1 - <1 <1 <1
Phenols <1 - <1 <1 <1
S+sulphides as S <1 - <1 344 344
SO4-- <1 - 8 1536 1,544
Sr+compounds as Sr - - <1 <1 <1
Suspended solids 2,850 - 3,870 219,800 226,500
TOC <1 - <1 <1 <1
Vinyl chloride monomer <1 - <1 <1 <1
Zn+compounds as Zn <1 - <1 <1 <1
BCAL 18 LCA Grocery Bags
Table 8. Generation of solid waste (in milligrams resulting from the recyclable PAPER
bag LCA. Based on consumer use & collection of 1000 bags. Totals may not agree
because of rounding.
Solid waste (mg) Fuel prod’n Fuel use Transport Process Total
Construction waste <1 - <1 <1 <1
Inert chemical <1 - <1 275 276
Metals <1 - <1 1,350 1,350
Mineral waste 2,590 - 38,500 1889,000 230,000
Mixed industrial -26,300 - 1,550 22,900 -1,860
Municipal solid waste -383,000 - - - -383,000
Paper <1 - <1 <1 <1
Plastic containers <1 - <1 - <1
Plastics <1 - <1 389 390
Putrescibles <1 - 11 <1 11
Regulated chemicals 67,500 - 3 85 67,600
Slags/ash 921,000 5,290 15,000 5,380 947,000
Tailings 81 - 1,290 4 1,380
Unregulated chemicals 51,200 - 51 820 52,040
Unspecified refuse 55,300 - <1 282,000 337,000
Waste returned to mine 2,202,000 - 1,420 345 2,203,000
Waste to compost - - - 1,290,000 1,290,000
Waste to incinerator 1 - 18 16 35
Waste to recycle <1 - <1 2,544,000 2,544,000
Wood waste <1 - <1 306,000 306,000
Wood pallets to
recycle
<1 - <1 - <1
RECYCLABLE PLASTIC BAG SYSTEM
The results of the LCA for the recyclable plastic bag system are presented below, each
describing some aspect of the behavior of the systems examined. In all cases, the
following tables refer to the gross or cumulative totals when all operations are traced
back to the extraction of raw materials from the earth and are based on the consumer use
and collection of 1000 bags and 1500 bags. The subsequent disposal operations of
recycling, composting, incineration with energy recovery and landfill are not included in
these results tables and will be discussed separately.
Table 9A. Gross energy (in MJ), required for the recyclable PLASTIC bag LCA. Based
on consumer use & collection of 1000 bags. Totals may not agree because of rounding.
Fuel type Fuel prod’n &
delivery
Energy content
of fuel
Transport
energy
Feedstock
energy
Total energy
Electricity 103 42 3 0 148
Oil 2 35 7 156 199
Other 2 37 0 123 162
Total 106 114 11 279 509
BCAL 19 LCA Grocery Bags
Table 9B. Gross energy (in MJ), required for the recyclable PLASTIC bag LCA. Based
on consumer use & collection of 1500 bags. Totals may not agree because of rounding.
Fuel type Fuel prod’n &
delivery
Energy content
of fuel
Transport
energy
Feedstock
energy
Total energy
Electricity 154 63 5 0 222
Oil 3 53 11 233 299
Other 2 55 1 185 242
Total 159 171 16 418 763
Table 10A. Gross primary fossil fuels and feedstocks, expressed as energy (in MJ ),
required for the recyclable PLASTIC bag LCA. Based on consumer use & collection of
1000 bags. Totals may not agree because of rounding.
Fuel prod’n Fuel use Transport Feedstock Total
Coal 43 21 1 0 65
Oil 5 37 8 155 206
Gas 23 46 1 116 186
Hydro 4 2 0 - 6
Nuclear 26 11 1 - 38
Lignite 0 0 0 - 0
Wood 0 3 0 7 9
Sulfur 0 0 0 0 0
Hydrogen 0 0 0 - 0
Biomass (solid) 3 1 0 0 4
Recovered energy 0 -7 0 - -7
Geothermal 0 0 0 - 0
Unspecified 0 0 0 - 0
Solar 0 0 0 - 0
Biomass (liqd/gas) 0 0 0 - 0
Industrial waste 0 0 0 0 0
Municipal Waste 1 0 0 - 1
Wind 0 0 0 - 0
Totals 106 114 11 279 509
BCAL 20 LCA Grocery Bags
Table 10B. Gross primary fossil fuels and feedstocks, expressed as energy (in MJ ),
required for the recyclable PLASTIC bag LCA. Based on consumer use & collection of
1500 bags. Totals may not agree because of rounding.
Fuel prod’n Fuel use Transport Feedstock Total
Coal 65 31 2 0 98
Oil 8 56 12 233 309
Gas 35 69 2 175 279
Hydro 6 3 0 - 9
39 16 1 1 - 57
Lignite 0 0 0 - 0
Wood 0 4 0 10 14
Sulfur 0 0 0 0 0
Hydrogen 0 0 0 - 0
Biomass (solid) 4 2 0 0 6
Recovered energy 0 -11 0 - -11
Geothermal 0 0 0 - 0
Unspecified 0 0 0 - 0
Solar 0 0 0 - 0
Biomass (liqd/gas) 0 0 0 - 0
Industrial waste 0 0 0 0 0
Municipal Waste 1 0 0 - 1
Wind 0 0 0 - 0
Totals 159 171 16 418 763
Table 11A. Gross primary fossil fuels and feedstocks, expressed as mass (in milligrams),
required the recyclable PLASTIC bag LCA. Based on consumer use & collection of 1000
bags. Totals may not agree because of rounding.
Crude oil…………….. 4,571,000
Gas/condensate……… 3,065,000
Coal…………………. 2,259,000
Metallurgical coal…... 6,060
Lignite ……………. 670
Peat …………………. 7,920
Wood (50% water)….. 809,000
Biomass (incl. water)… 498,000
Table 11B. Gross primary fossil fuels and feedstocks, expressed as mass (in milligrams),
required the recyclable PLASTIC bag LCA. Based on consumer use & collection of 1500
bags. Totals may not agree because of rounding.
Crude oil…………….. 6,857,000
Gas/condensate……… 4,598,000
Coal…………………. 3,388,000
Metallurgical coal…... 9,100
Lignite ……………. 1,010
Peat …………………. 11,900
Wood (50% water)….. 1,212,000
Biomass (incl. water)… 746,000
BCAL 21 LCA Grocery Bags
Table 12A. Gross water resources (in milligrams) required for the recyclable PLASTIC
bag LCA. Based on consumer use & collection of 1000 bags. Totals may not agree
because of rounding.
Source Use in process Use in cooling Totals
Public supply 31,900,000 1,230,000 33,150,000
River/canal 4,970,000 2,520,000 7,480,000
Sea 819,000 58,600,000 59,400,000
Unspecified 5,120,000 105,400,000 110,600,000
Well 425,000 66,000 138,000
Total 43,250,000 167,800,000 211,100,000
Table 12B. Gross water resources (in milligrams) required for the recyclable PLASTIC
bag LCA. Based on consumer use & collection of 1500 bags. Totals may not agree
because of rounding.
Source Use in process Use in cooling Totals
Public supply 47,900,000 1,850,000 49,700,000
River/canal 7,460,000 3,780,000 11,200,000
Sea 1,230,000 87,900,000 89,100,000
Unspecified 7,680,000 158,000,000 166,000,000
Well 638,000 99,000 207,000
Total 64,900,000 252,000,000 317,000,000
BCAL 22 LCA Grocery Bags
Table 13A. Gross other raw materials (in milligrams required for the recyclable
PLASTIC bag LCA. Based on consumer use & collection of 1000 bags. Totals may not
agree because of rounding.
Raw material Input in mg
Air 1,436,000
Animal matter <1
Barites 343
Bauxite 111
Bentonite 231
Calcium sulphate (CaSO4) 22
Clay 235
Cr 7
Cu <1
Dolomite 184
Fe 15,000
Feldspar <1
Ferromanganese 14
Fluorspar 3
Granite <1
Gravel 56
Hg <1
Limestone (CaCO3) 542,000
Mg <1
N2 823,000
Ni <1
O2 110,000
Olivine 141
Pb 87
Phosphate as P205 743
Potassium chloride (KCl) 252
Quartz (SiO2) 0
Rutile 272,000
S (bonded) 13
S (elemental) 1,520
Sand (SiO2) 935
Shale 63
Sodium chloride (NaCl) 51,200
Sodium nitrate (NaNO3) 0
Talc <1
Unspecified <1
Zn 266
BCAL 23 LCA Grocery Bags
Table 13B. Gross other raw materials (in milligrams required for the recyclable
PLASTIC bag LCA. Based on consumer use & collection of 1500 bags. Totals may not
agree because of rounding.
Raw material Input in mg
Air 2,154,000
Animal matter <1
Barites 515
Bauxite 166
Bentonite 347
Calcium sulphate (CaSO4) 33
Clay 353
Cr 10
Cu <1
Dolomite 276
Fe 22,600
Feldspar <1
Ferromanganese 21
Fluorspar 4
Granite <1
Gravel 83
Hg <1
Limestone (CaCO3) 812,000
Mg <1
N2 1,235,000
Ni <1
O2 165,000
Olivine 212
Pb 131
Phosphate as P205 1,120
Potassium chloride (KCl) 379
Quartz (SiO2) 0
Rutile 408,000
S (bonded) 20
S (elemental) 2,270
Sand (SiO2) 1,400
Shale 94
Sodium chloride (NaCl) 76,700
Sodium nitrate (NaNO3) 0
Talc <1
Unspecified <1
Zn 399
BCAL 24 LCA Grocery Bags
Table 14A. Gross air emissions (in milligrams) resulting from the recyclable PLASTIC
bag LCA. Based on consumer use & collection of 1000 bags. Totals may not agree
because of rounding.
Air emissions/mg Fuel prod’n Fuel use Transport Process Biomass Fugit
ive
Total
Dust (PM10) 6,340 540 430 7,000 - - 14,300
CO 10,800 48,900 5,110 2,570 - - 67,400
CO2 8,570,000 5,390,000 551,000 953,000 -427,000 - 15,030,000
SOX as SO2 35,700 9,130 2,000 3,640 - - 50,500
H2S <1 - <1 14 - - 14
Mercaptan <1 <1 - 4 - 4
NOX as NO2 28,500 10,000 6,060 870 - - 45,400
Aledhyde (-CHO) <1 - <1 <1 - - <1
Aromatic HC not spec 1 - 22 380 - - 403
Cd+compounds as Cd <1 - <1 - - <1
CH4 40,900 1,660 3 20,700 - - 63,300
Cl2 <1 - <1 29 - - 29
Cr+compounds as Cr <1 - <1 - - - <1
CS2 <1 - <1 <1 - <1
Cu+compounds as Cu <1 - <1 - - - <1
Dichlorethane (DCE) <1 - <1 <1 - <1 <1
Ethylene C2H4 - - <1 - - - <1
F2 <1 - <1 <1 - - <1
H2 68 2 <1 754 - - 824
H2SO4 <1 - <1 <1 - - <1
HCl 1,220 95 <1 3 - - 1,320
HCN <1 - <1 <1 - - <1
HF 46 1 <1 <1 - - 47
Hg+compounds as Hg <1 - <1 <1 -- - <1
Hydrocarbons not spec 7,430 920 1,670 13,100 - - 23,100
Metals not specified 6 5 <1 3 - - 14
Methylene chloride CH2 <1 - <1 <1 - - <1
N2O <1 <1 <1 - - - <1
NH3 <1 - <1 8 - - 8
Ni compounds as Ni <1 - <1 - - - <1
NMVOC <1 - <1 993 - - 994
Organics <1 <1 <1 367 - - 367
Organo-chlorine not spec <1 - <1 <1 - - <1
Pb+compounds as Pb <1 <1 <1 <1 - - <1
Polycyclic hydrocarbon <1 - <1 <1 - - <1
Sb+compounds as Sb - - <1 - - - <1
Vinyl chloride monomer <1 - <1 <1 - <1 <1
Zn+compounds as Zn <1 - <1 <1 - - <1
BCAL 25 LCA Grocery Bags
Table 14B. Carbon dioxide equivalents corresponding to the gross air emissions (in
milligrams) resulting from the recyclable PLASTIC bag LCA. Based on consumer use &
collection of 1000 bags. Totals may not agree because of rounding.
Type/mg Fuel prod’n Fuel use Transport Process Biomass Total
20 year equiv 11,100,000 5,590,000 566,000 2,280,000 -427,000 19,200,000
100 year equiv 9,550,000 5,530,000 566,000 1,470,000 -427,000 16,700,000
500 year equiv 8,900,000 5,500,000 566,000 1,140,000 -427,000 15,700,000
Table 14C. Gross air emissions (in milligrams) resulting from the recyclable PLASTIC
bag LCA. Based on consumer use & collection of 1500 bags. Totals may not agree
because of rounding.
Air emissions/mg Fuel prod’n Fuel use Transport Process Biomass Fugit
ive
Total
Dust (PM10) 9,500 811 644 10,500 - - 21,500
CO 16,100 73,400 7,670 3,850 - - 101,000
CO2 12,900,000 8,082,000 826,000 1,429,000 -640,000 - 22,550,000
SOX as SO2 53,500 13,700 3,000 5,460 - - 75,700
H2S <1 - <1 21 - - 22
Mercaptan <1 <1 - 6 - 6
NOX as NO2 42,700 15,100 9,090 1,310 - - 68,100
Aledhyde (-CHO) <1 - <1 <1 - - <1
Aromatic HC not spec 2 - 33 570 - - 604
Cd+compounds as Cd <1 - <1 - - <1
CH4 61,400 2,490 4 31,090 - - 95,000
Cl2 <1 - <1 43 - - 43
Cr+compounds as Cr <1 - <1 - - - <1
CS2 <1 - <1 <1 - <1
Cu+compounds as Cu <1 - <1 - - - <1
Dichlorethane (DCE) <1 - <1 <1 - <1 <1
Ethylene C2H4 - - <1 - - - <1
F2 <1 - <1 <1 - - <1
H2 102 2 <1 1,130 - - 1,240
H2SO4 <1 - <1 <1 - - <1
HCl 1,830 142 1 5 - - 1,980
HCN <1 - <1 <1 - - <1
HF 69 2 <1 <1 - - 71
Hg+compounds as Hg <1 - <1 <1 -- - <1
Hydrocarbons not spec 11,100 1,380 2,510 19,700 - - 34,700
Metals not specified 9 7 <1 5 - - 21
Methylene chloride CH2 <1 - <1 <1 - - <1
N2O <1 <1 <1 - - - <1
NH3 <1 - <1 12 - - 12
Ni compounds as Ni <1 - <1 - - - <1
NMVOC <1 - <1 1,490 - - 1,490
Organics <1 <1 <1 551 - - 551
Organo-chlorine not spec <1 - <1 <1 - - <1
Pb+compounds as Pb <1 <1 <1 <1 - - <1
Polycyclic hydrocarbon <1 - <1 <1 - - <1
Sb+compounds as Sb - - <1 - - - <1
Vinyl chloride monomer <1 - <1 <1 - <1 <1
Zn+compounds as Zn <1 - <1 <1 - - <1
BCAL 26 LCA Grocery Bags
Table 14D. Carbon dioxide equivalents corresponding to the gross air emissions (in
milligrams) resulting from the recyclable PLASTIC bag LCA. Based on consumer use &
collection of 1500 bags. Totals may not agree because of rounding.
Type/mg Fuel prod’n Fuel use Transport Process Biomass Total
20 year equiv 16,700,000 8,390,000 849,000 3,420,000 -641,000 28,800,000
100 year equiv 14,300,000 8,300,000 849,000 2,210,000 -641,000 25,100,000
500 year equiv 13,400,000 8,250,000 849,000 1,710,000 -641,000 23,600,000
BCAL 27 LCA Grocery Bags
Table 15A. Gross water emissions (in milligrams), resulting from the recyclable
PLASTIC bag LCA. Based on consumer use & collection of 1000 bags. Totals may not
agree because of rounding.
Fuel prod’n Fuel use Transport Process Total
COD 9 - 8 5390 5,410
BOD 2 - <1 543 545
Acid (H+) 4 - <1 9 13
Al+compounds as Al <1 - <1 4 4
Ammonium compounds as NH4 5 - <1 11 17
AOX <1 - <1 <1 <1
As+compounds as As - - <1 <1 <1
BrO3-- <1 - <1 <1 <1
Ca+compounds as Ca <1 - <1 20 20
Cd+compounds as Cd - - <1 - <1
Cl- 3 - 8 3,060 3,070
ClO3-- <1 - <1 15 15
CN- <1 - <1 <1 <1
CO3-- - - <1 181 182
Cr+compounds as Cr <1 - <1 <1 <1
Cu+compounds as Cu <1 - <1 1 1
Detergent/oil <1 - <1 39 40
Dichloroethane (DCE) <1 - <1 <1 <1
Dioxin/furan as Teq - - <1 - <1
Dissolved chlorine <1 - <1 <1 <1
Dissolved organics (non-HC) 3 - <1 44 47
Dissolved solids not specified 2 - 2 947 952
F- <1 - <1 <1 <1
Fe+compounds as Fe <1 - <1 <1 <1
Hg+compounds as Hg <1 - <1 <1 <1
Hydrocarbons not specified 26 <1 <1 3 30
K+compounds as K <1 - <1 11 11
Metals not specified elsewhere <1 - <1 54 55
Mg+compounds as Mg <1 - <1 <1 <1
Mn+compounds as Mn - - <1 <1 <1
Na+compounds as Na 2 - 5 3,136 3,143
Ni+compounds as Ni <1 - <1 <1 <1
NO3- 1 - <1 13 13
Organo-chlorine not specified <1 - <1 <1 <1
Organo-tin as Sn - - <1 - <1
Other nitrogen as N <1 - <1 46 47
Other organics not specified <1 - <1 <1 <1
P+compounds as P <1 - <1 7 7
Pb+compounds as PB <1 - <1 <1 <1
Phenols <1 - <1 10 10
S+sulphides as S <1 - <1 2 2
SO4-- <1 - 2 4,097 4,098
Sr+compounds as Sr - - <1 <1 <1
Suspended solids 573 - 861 78,300 79,800
TOC <1 - <1 60 60
Vinyl chloride monomer <1 - <1 <1 <1
Zn+compounds as Zn <1 - <1 <1 <1
BCAL 28 LCA Grocery Bags
Table 15B. Gross water emissions (in milligrams), resulting from the recyclable
PLASTIC bag LCA. Based on consumer use & collection of 1500 bags. Totals may not
agree because of rounding.
Fuel prod’n Fuel use Transport Process Total
COD 14 - 12 8,080 8,110
BOD 3 - <1 814 817
Acid (H+) 6 - <1 13 19
Al+compounds as Al <1 - <1 5 5
Ammonium compounds as NH4 7 - <1 17 25
AOX <1 - <1 <1 <1
As+compounds as As - - <1 <1 <1
BrO3-- <1 - <1 <1 <1
Ca+compounds as Ca <1 - <1 30 30
Cd+compounds as Cd - - <1 - <1
Cl- 5 - 11 4,590 4,610
ClO3-- <1 - <1 22 22
CN- <1 - <1 <1 <1
CO3-- - - 1 272 273
Cr+compounds as Cr <1 - <1 <1 <1
Cu+compounds as Cu <1 - <1 2 2
Detergent/oil <1 - <1 59 60
Dichloroethane (DCE) <1 - <1 <1 <1
Dioxin/furan as Teq - - <1 - <1
Dissolved chlorine <1 - <1 1 1
Dissolved organics (non-HC) 4 - <1 66 70
Dissolved solids not specified 3 - 3 1,420 1,430
F- <1 - <1 <1 <1
Fe+compounds as Fe <1 - <1 <1 <1
Hg+compounds as Hg <1 - <1 <1 <1
Hydrocarbons not specified 39 <1 <1 4 45
K+compounds as K <1 - <1 16 16
Metals not specified elsewhere 1 - <1 81 83
Mg+compounds as Mg <1 - <1 <1 <1
Mn+compounds as Mn - - <1 <1 <1
Na+compounds as Na 3 - 8 4,700 4,710
Ni+compounds as Ni <1 - <1 <1 <1
NO3- <1 - <1 19 19
Organo-chlorine not specified <1 - <1 <1 <1
Organo-tin as Sn - - <1 - <1
Other nitrogen as N 1 - <1 69 70
Other organics not specified <1 - <1 <1 <1
P+compounds as P <1 - <1 10 10
Pb+compounds as PB <1 - <1 <1 <1
Phenols <1 - <1 15 15
S+sulphides as S <1 - <1 3 3
SO4-- <1 - 3 6,150 6,150
Sr+compounds as Sr - - <1 <1 <1
Suspended solids 860 - 1,290 117,500 119,600
TOC <1 - <1 90 90
Vinyl chloride monomer <1 - <1 <1 <1
Zn+compounds as Zn <1 - <1 1 1
BCAL 29 LCA Grocery Bags
Table 16A. Generation of solid waste (in milligrams resulting from the recyclable
PLASTIC bag LCA. Based on consumer use & collection of 1000 bags. Totals may not
agree because of rounding.
Solid waste (mg) Fuel prod’n Fuel use Transport Process Total
Construction waste <1 - <1 <1 <1
Inert chemical <1 - <1 3,446 3,446
Metals <1 - <1 301 301
Mineral waste 974 - 8,564 324,200 333,700
Mixed industrial -11,800 - 345 5,520 -5,950
Municipal solid waste -79,800 - - 22,500 -57,300
Paper <1 - <1 <1 <1
Plastic containers <1 - <1 - <1
Plastics <1 - <1 53,600 53,600
Putrescibles <1 - 2 7 10
Regulated chemicals 9,040 - <1 4,720 13,800
Slags/ash 180,000 4,460 3,330 1,660 189,000
Tailings 16 - 287 1,048 1,350
Unregulated chemicals 6,810 - 11 7,190 14,000
Unspecified refuse 7,350 - <1 62,900 70,200
Waste returned to mine 443,000 - 316 872 444,400
Waste to compost - - - 9,290 9,290
Waste to incinerator <1 - 4 4,370 4,380
Waste to recycle <1 - <1 33,200 33,200
Wood waste <1 - <1 2,330 2,330
Wood pallets to
recycle
<1 - <1 298,000 298,000
Table 16B. Generation of solid waste (in milligrams resulting from the recyclable
PLASTIC bag LCA. Based on consumer use & collection of 1500 bags. Totals may not
agree because of rounding.
Solid waste (mg) Fuel prod’n Fuel use Transport Process Total
Construction waste <1 - <1 <1 <1
Inert chemical <1 - <1 5,170 5,170
Metals <1 - <1 452 452
Mineral waste 1,460 - 12,800 486,000 501,000
Mixed industrial -17,700 - 517 8,280 -8,930
Municipal solid waste 1119,700 - - 33,800 -85,900
Paper <1 - <1 <1 <1
Plastic containers <1 - <1 - <1
Plastics <1 - <1 80,400 80,400
Putrescibles <1 - 4 11 14
Regulated chemicals 13,600 - <1 7,080 20,600
Slags/ash 270,000 6,680 4,990 2,480 284,000
Tailings 24 - 430 1,570 2,030
Unregulated chemicals 10,200 - 17 10,800 21,000
Unspecified refuse 11,030 - <1 94,300 105,400
Waste returned to mine 665,000 - 475 1,310 667,000
Waste to compost - - - 13,900 13,900
Waste to incinerator <1 - 6 6,560 6,560
Waste to recycle <1 - <1 49,800 49,800
Wood waste <1 - <1 3,500 3,500
Wood pallets to
recycle
<1 - <1 447,000 447,000
BCAL 30 LCA Grocery Bags
THE COMPOSTABLE PLASTIC BAG SYSTEM
The results of the LCA for the compostable plastic bag system are presented below, each
describing some aspect of the behavior of the systems examined. In all cases, the
following tables refer to the gross or cumulative totals when all operations are traced
back to the extraction of raw materials from the earth and are based on the consumer use
and collection of 1000 bags and 1500 bags. The subsequent disposal operations of
recycling, composting, incineration with energy recovery and landfill are not included in
these results tables and will be discussed separately.
Table 17A. Gross energy (in MJ), required for the COMPOSTABLE PLASTIC bag LCA.
Based on consumer use & collection of 1000 bags. Totals may not agree because of rounding.
Fuel type Fuel prod’n &
delivery
Energy content
of fuel
Transport
energy
Feedstock
energy
Total energy
Electricity 221 103 1 0 325
Oil 29 279 36 1 345
Other 15 277 1 417 710
Total 265 659 38 418 1380
Table 17B. Gross energy (in MJ), required for the COMPOSTABLE PLASTIC bag LCA.
Based on consumer use & collection of 1500 bags. Totals may not agree because of rounding.
Fuel type Fuel prod’n &
delivery
Energy content
of fuel
Transport
energy
Feedstock
energy
Total energy
Electricity 331 154 2 0 487
Oil 44 418 54 1 518
Other 22 416 2 625 1065
Total 398 988 57 627 2070
Table 18A. Gross primary fossil fuels and feedstocks, expressed as energy (in MJ ), required for
the COMPOSTABLE PLASTIC bag LCA. Based on consumer use & collection of 1000 bags.
Totals may not agree because of rounding.
Fuel prod’n Fuel use Transport Feedstock Total
Coal 113 48 1 0 161
Oil 34 281 37 1 353
Gas 44 301 1 360 705
Hydro 7 2 0 - 9
Nuclear 62 11 0 - 74
Lignite 0 0 0 - 0
Wood 0 7 0 18 26
Sulfur 0 0 0 0 0
Hydrogen 0 0 0 0 0
Biomass (solid) 6 2 0 39 47
Recovered energy -2 -5 0 - -8
Geothermal 0 0 0 - 0
Unspecified 0 0 0 - 0
Solar 0 0 0 - 0
Biomass (liqd/gas) 0 0 0 - 0
Industrial waste 1 0 0 - 1
Municipal Waste 1 0 0 - 1
BCAL 31 LCA Grocery Bags
Table 18B. Gross primary fossil fuels and feedstocks, expressed as energy (in MJ ), required for
the COMPOSTABLE PLASTIC bag LCA. Based on consumer use & collection of 1500 bags.
Totals may not agree because of rounding.
Fuel prod’n Fuel use Transport Feedstock Total
Coal 169 72 1 0 241
Oil 51 422 55 1 529
Gas 65 451 1 540 1,057
Hydro 11 3 0 - 14
Nuclear 94 17 0 - 111
Lignite 0 0 0 - 0
Wood 0 11 0 27 38
Sulfur 0 0 0 0 0
Hydrogen 0 0 0 0 0
Biomass (solid) 9 4 0 58 71
Recovered energy -4 -8 0 - -11
Geothermal 0 0 0 - 0
Unspecified 0 0 0 - 0
Solar 0 0 0 - 0
Biomass (liqd/gas) 0 0 0 - 0
Industrial waste 1 0 0 - 1
Municipal Waste 1 1 0 - 2
Wind 0 16 0 - 16
Totals 398 988 57 627 2,070
Table 19A. Gross primary fossil fuels and feedstocks, expressed as mass (in milligrams),
required the COMPOSTABLE PLASTIC bag LCA. Based on consumer use & collection of
1000 bags. Totals may not agree because of rounding.
Crude oil…………….. 7,840,000
Gas/condensate……… 14,020,000
Coal…………………. 5,760,000
Metallurgical coal…... 17,000
Lignite ……………. 0
Peat …………………. 7
Wood (50% water)….. 2,210,000
Biomass (incl. water)… 986,000
Table 19B. Gross primary fossil fuels and feedstocks, expressed as mass (in milligrams),
required the COMPOSTABLE PLASTIC bag LCA. Based on consumer use & collection of
1500 bags. Totals may not agree because of rounding.
Crude oil…………….. 11,760,000
Gas/condensate……… 21,030,000
Coal…………………. 8,630,000
Metallurgical coal…... 25,000
Lignite ……………. 0
Peat …………………. 10
Wood (50% water)….. 3,310,000
Biomass (incl. water)… 1,480,000
BCAL 32 LCA Grocery Bags
Table 20A. Gross water resources (in milligrams) required for the COMPOSTABLE PLASTIC
bag LCA. Based on consumer use & collection of 1000 bags. Totals may not agree because of
rounding.
Source Use in process Use in cooling Totals
Public supply 2,540,000,000 19,200,000 2,560,000,000
River/canal 3,870 1,690,000 1,700,000
Sea 13,100 2,710,000 2,720,000
Unspecified 36,600,000 6,270,000 42,900,000
Well 564,000 49 564,000
Totals 2,580,000,000 29,900,000 2,607,000,000
Table 20B. Gross water resources (in milligrams) required for the COMPOSTABLE PLASTIC
bag LCA. Based on consumer use & collection of 1500 bags. Totals may not agree because of
rounding.
Source Use in process Use in cooling Totals
Public supply 3,810,000,000 28,800,000 3,840,000,000
River/canal 5,810 2,540,000 2,550,000
Sea 19,650 4,065,000 4,080,000
Unspecified 54,900,000 9,410,000 64,350,000
Well 846,000 74 846,000
Totals 3,870,000,000 44,900,000 3,910,000,000
BCAL 33 LCA Grocery Bags
Table 21A. Gross other raw materials (in milligrams) required for the COMPOSTABLE
PLASTIC bag LCA. Based on consumer use & collection of 1000 bags. Totals may not agree
because of rounding.
Raw material Input in mg
Air 1,460,000
Animal matter 0
Barites 1,700
Bauxite 4,000
Bentonite 99
Calcium sulphate (CaSO4) <1
Clay 34,200
Cr 19
Cu 0
Dolomite 513
Fe 47,300
Feldspar 0
Ferromanganese 38
Fluorspar 3
Granite 0
Gravel 155
Hg 0
Limestone (CaCO3) 4,230,000
Mg 0
N2 for reaction 17,900
Ni 0
O2 for reaction 1,030
Olivine 394
Pb 260
Phosphate as P205 12,300
Potassium chloride (KCl) 23,000
Quartz (SiO2) 0
Rutile 0
S (bonded) 401,000
S (elemental) 23,700
Sand (SiO2) 22,400
Shale 2
Sodium chloride (NaCl) 261,000
Sodium nitrate (NaNO3) 0
Talc 0
Unspecified 0
Zn 9
BCAL 34 LCA Grocery Bags
Table 21B. Gross other raw materials (in milligrams) required for the COMPOSTABLE
PLASTIC bag LCA. Based on consumer use & collection of 1500 bags. Totals may not agree
because of rounding.
Raw material Input in mg
Air 2,190,000
Animal matter 0
Barites 2,550
Bauxite 6,010
Bentonite 148
Calcium sulphate (CaSO4) <1
Clay 51,300
Cr 28
Cu 0
Dolomite 769
Fe 71,000
Feldspar 0
Ferromanganese 57
Fluorspar 5
Granite 0
Gravel 232
Hg 0
Limestone (CaCO3) 6,350,000
Mg 0
N2 for reaction 26,800
Ni 0
O2 for reaction 1,550
Olivine 591
Pb 390
Phosphate as P205 18,400
Potassium chloride (KCl) 34,500
Quartz (SiO2) 0
Rutile 0
S (bonded) 602,000
S (elemental) 35,500
Sand (SiO2) 33,600
Shale 3
Sodium chloride (NaCl) 392,000
Sodium nitrate (NaNO3) 0
Talc 0
Unspecified 0
Zn 14
BCAL 35 LCA Grocery Bags
Table 22A. Gross air emissions (in milligrams) resulting from the COMPOSTABLE PLASTIC
bag LCA. Based on consumer use & collection of 1000 bags. Totals may not agree because of
rounding.
Air emissions/mg Fuel prod’n Fuel use Transport Process Biomass Fugit
ive
Total
Dust (PM10) 9,120 520 1,500 42,200 - - 53,400
CO 16,000 4,900 16,900 4,100 - - 41,900
CO2 13,860,000 2,620,000 2,580,000 41,800,000 -4,230,000 - 56,600,000
SOX as SO2 54,900 7,210 21,100 192,000 - - 275,000
H2S 0 0 1 40 - - 41
Mercaptan 0 0 0 11 - 11
NOX as NO2 50,000 8,260 24,500 221,500 - - 304,000
Aledhyde (-CHO) 0 0 0 0 - - 0
Aromatic HC not spec 2 - 67 4 - - 74
Cd+compounds as Cd 0 - 0 - - 0
CFC/HCFC/HFC not sp 0 - 0 0 - 0
CH4 59,600 1,060 98 224,000 - - 284,000
Cl2 0 - 0 0 - - 0
Cr+compounds as Cr 0 - 0 - - - 0
CS2 0 - 0 0 - 0
Cu+compounds as Cu 0 - 0 - - - 0
Dichlorethane (DCE) 0 - 0 0 - 0 0
Ethylene C2H4 - - 0 - - - 0
F2 0 - 0 0 - - 0
H2 38 0 0 226 - - 264
H2SO4 0 - 0 0 - - 0
HCl 2,140 6 3 871 - - 3,020
HCN 0 - 0 0 - - 0
HF 81 0 0 0 - - 81
Hg+compounds as Hg 0 - 0 0 -- - 0
Hydrocarbons not spec 13,800 1,720 6,400 100 - - 22,000
Metals not specified 8 4 0 0 0 - 12
Molybdenum - - - 1 - - 1
N2O 0 0 0 53,100 - - 53,100
NH3 0 - 0 39 - - 39
Ni compounds as Ni 0 - 0 - - - 0
NMVOC 0 72 410 46,400 - - 46,900
Organics 0 0 0 119 - - 119
Organo-chlorine not spec 0 - 0 16 - - 16
Pb+compounds as Pb 0 0 0 0 - - 0
Polycyclic hydrocarbon 0 - 0 0 - - 0
Titanium - - - 119 - - 119
Vinyl chloride monomer 0 - 0 0 - - 0
Zn+compounds as Zn 0 - 0 0 - - 0
Table 22B. Carbon dioxide equivalents corresponding to the gross air emissions (in milligrams) from the
COMPOSTABLE PLASTIC bag LCA. Based on consumer use & collection of 1000 bags. Totals may not
agree because of rounding.
Type/mg Fuel prod’n Fuel use Transport Process Biomass Total
20 year equiv 17,630,000 2,700,000 2,640,000 70,200,000 -4,230,000 89,000,000
100 year equiv 15,300,000 2,660,000 2,640,000 62,640,000 -4,230,000 79,000,000
500 year equiv 14,300,000 2,640,000 2,400,000 51,600,000 -4,230,000 67,000,000
BCAL 36 LCA Grocery Bags
Table 22C. Gross air emissions (in milligrams) resulting from the COMPOSTABLE PLASTIC
bag LCA. Based on consumer use & collection of 1500 bags. Totals may not agree because of
rounding.
Air emissions/mg Fuel prod’n Fuel use Transport Process Biomass Fugit
ive
Total
Dust (PM10) 13,700 780 2,260 63,400 - - 80,100
CO 24,000 7,360 25,300 6,150 - - 62,900
CO2 20,800,000 3,930,000 3,880,000 62,700,000 -6,340,000 - 84,900,000
SOX as SO2 82,400 10,800 31,600 288,000 - - 413,000
H2S 0 0 2 60 - - 62
Mercaptan 0 0 0 17 - 17
NOX as NO2 74,900 12,400 36,700 332,000 - - 456,000
Aledhyde (-CHO) 0 0 0 0 - - 0
Aromatic HC not spec 3 - 101 7 - - 111
Cd+compounds as Cd 0 - 0 - - 0
CFC/HCFC/HFC not sp 0 - 0 0 - 0
CH4 89,500 1,590 147 335,000 - - 426,000
Cl2 0 - 0 0 - - 0
Cr+compounds as Cr 0 - 0 - - - 0
CS2 0 - 0 0 - 0
Cu+compounds as Cu 0 - 0 - - - 0
Dichlorethane (DCE) 0 - 0 0 - - 0
Ethylene C2H4 - - 0 - - - 0
F2 0 - 0 0 - - 0
H2 57 0 0 339 - - 397
H2SO4 0 - 0 0 - - 0
HCl 3,220 8 5 1,310 - - 4,540
HCN 0 - 0 0 - - 0
HF 121 0 0 0 - - 122
Hg+compounds as Hg 0 - 0 0 -- - 0
Hydrocarbons not spec 20,600 2,580 9,590 150 - - 33,000
Metals not specified 13 5 0 0 0 - 18
Molybdenum - - - 2 - - 2
N2O 0 0 0 79,600 - - 79,600
NH3 0 - 0 59 - - 59
Ni compounds as Ni 0 - 0 - - - 0
NMVOC 1 108 615 69,600 - - 70,300
Organics 0 0 0 178 - - 178
Organo-chlorine not spec 0 - 0 24 - - 24
Pb+compounds as Pb 0 0 0 0 - - 0
Polycyclic hydrocarbon 0 - 0 0 - - 0
Titanium - - - 178 - - 178
Vinyl chloride monomer 0 - 0 0 - - 0
Zn+compounds as Zn 0 - 0 0 - - 0
BCAL 37 LCA Grocery Bags
Table 22D. Carbon dioxide equivalents corresponding to the gross air emissions (in milligrams)
from the COMPOSTABLE PLASTIC bag LCA. Based on consumer use & collection of 1500
bags. Totals may not agree because of rounding.
Type/mg Fuel prod’n Fuel use Transport Process Biomass Total
20 year equiv 26,400,000 4,050,000 3,960,000 105,300,000 -6,350,000 134,000,000
100 year equiv 23,000,000 3,990,000 3,960,000 94,000,000 -6,350,000 119,000,000
500 year equiv 21,500,000 3,960,000 3,600,000 77,400,000 -6,350,000 101,000,000
BCAL 38 LCA Grocery Bags
Table 23A. Gross water emissions (in milligrams), resulting from the COMPOSTABLE
PLASTIC bag LCA. Based on consumer use & collection of 1000 bags. Totals may not agree
because of rounding.
Fuel prod’n Fuel use Transport Process Total
COD 15 2 57 59,700 59,800
BOD 4 - 4 3,190 3,200
Acid (H+) 2 - 0 0 4
Al+compounds as Al 0 - 0 2 2
Ammonium compounds as NH4 5 - 2 0 7
AOX 0 - 0 10 10
As+compounds as As - - 0 0 0
BrO3-- 0 - 0 0 0
Ca+compounds as Ca 0 - 0 201 201
Cd+compounds as Cd - - 0 - 0
Cl- 7 - 670 27,500 28,100
ClO3-- 0 - 0 2 2
CN- 0 - 0 0 0
CO3-- - - 2 5 7
Cr+compounds as Cr 0 - 0 0 0
Cu+compounds as Cu 0 - 0 0 0
Detergent/oil 0 - 2 3 5
Dichloroethane (DCE) 0 - 0 0 0
Dioxin/furan as Teq - - 0 - 0
Dissolved chlorine 0 - 0 0 0
Dissolved organics (non-HC) 6 - 0 0 6
Dissolved solids not specified 2 - 6 59 67
F- 0 - 6 0 6
Fe+compounds as Fe 0 - 1 20 22
Hg+compounds as Hg 0 - 0 0 0
Hydrocarbons not specified 0 0 1 334 337
K+compounds as K 0 - 0 2 2
Metals not specified elsewhere 0 - 0 52 52
Mg+compounds as Mg 0 - 0 2 2
Mn+compounds as Mn - - 0 0 0
Na+compounds as Na 3 - 15 1,270 1,290
Ni+compounds as Ni 0 - 0 0 0
NO3- 0 - 0 1,910 1,910
Organo-chlorine not specified 0 - 0 0 0
Organo-tin as Sn - - 0 - 0
Other nitrogen as N 0 - 0 4,300 4,300
Other organics not specified 0 - 0 0 0
P+compounds as P 0 - 0 41 41
Pb+compounds as PB 0 - 0 0 0
Phenols 0 - 0 0 0
S+sulphides as S 0 - 0 5 5
SO4-- 0 - 5 6,287 6,290
Sr+compounds as Sr - - 0 0 0
Suspended solids 945 - 2,660 396,000 399,000
TOC 0 - 15 2,460 2,480
Vinyl chloride monomer 0 - 0 0 0
Zn+compounds as Zn 0 - 0 0 0
BCAL 39 LCA Grocery Bags
Table 23B. Gross water emissions (in milligrams), resulting from the COMPOSTABLE
PLASTIC bag LCA. Based on consumer use & collection of 1500 bags. Totals may not agree
because of rounding.
Fuel prod’n Fuel use Transport Process Total
COD 22 2 86 89,500 89,600
BOD 6 - 6 4,790 4,800
Acid (H+) 4 - 0 1 5
Al+compounds as Al 0 - 0 3 3
Ammonium compounds as NH4 7 - 2 1 11
AOX 0 - 0 15 15
As+compounds as As - - 0 0 0
BrO3-- 0 - 0 0 0
Ca+compounds as Ca 0 - 0 302 302
Cd+compounds as Cd - - 0 - 0
Cl- 10 - 1,010 41,200 42,200
ClO3-- 0 - 0 2 2
CN- 0 - 0 0 0
CO3-- - - 3 7 10
Cr+compounds as Cr 0 - 0 0 0
Cu+compounds as Cu 0 - 0 0 0
Detergent/oil 0 - 2 4 7
Dichloroethane (DCE) 0 - 0 0 0
Dioxin/furan as Teq - - 0 - 0
Dissolved chlorine 0 - 0 0 0
Dissolved organics (non-HC) 9 - 0 1 10
Dissolved solids not specified 2 - 10 89 101
F- 0 - 9 0 9
Fe+compounds as Fe 0 - 2 31 33
Hg+compounds as Hg 0 - 0 0 0
Hydrocarbons not specified 1 1 2 501 505
K+compounds as K 0 - 0 3 3
Metals not specified elsewhere 0 - 0 76 76
Mg+compounds as Mg 0 - 0 3 3
Mn+compounds as Mn - - 0 0 0
Na+compounds as Na 4 - 23 1,900 1,930
Ni+compounds as Ni 0 - 0 0 0
NO3- 0 - 0 2,860 2,860
Organo-chlorine not specified 0 - 0 0 0
Organo-tin as Sn - - 0 - 0
Other nitrogen as N 0 - 0 6,440 6,440
Other organics not specified 0 - 0 0 0
P+compounds as P 0 - 0 62 62
Pb+compounds as PB 0 - 0 0 0
Phenols 0 - 0 0 0
S+sulphides as S 0 - 0 7 7
SO4-- 0 - 8 9,430 9,440
Sr+compounds as Sr - - 0 0 0
Suspended solids 1,420 - 3,990 594,000 599,000
TOC 0 - 23 3,690 3,710
Vinyl chloride monomer 0 - 0 0 0
Zn+compounds as Zn 0 - 0 0 0
BCAL 40 LCA Grocery Bags
Table 24A. Generation of solid waste (in milligrams) resulting from the COMPOSTABLE
PLASTIC bag LCA. Based on consumer use & collection of 1000 bags. Totals may not agree
because of rounding.
Solid waste (mg) Fuel prod’n Fuel use Transport Process Total
Construction waste 0 - 0 0 0
Inert chemical 0 - 0 5 5
Metals 0 - 0 822 822
Mineral waste 1,110 - 26,500 405,000 433,000
Mixed industrial -12,800 - 1,100 2,620 -9,080
Municipal solid waste -130,000 - - 205,000 75,000
Paper 0 - 0 0 0
Plastic containers 0 - 0 - 0
Plastics 0 - 0 1,580 1,580
Putrescibles 0 - 7 1 8
Regulated chemicals 18,400 - 4,830 133 23,400
Slags/ash 308,000 660 10,300 2,690,000 3,009,000
Tailings 27 - 15,900 284 16,300
Unregulated chemicals 14,000 - 0 82,400 96,400
Unspecified refuse 15,100 - 0 171,700 186,800
Waste returned to mine 731,000 - 980 108 732,100
Waste to compost - - - 25,400 25,400
Waste to incinerator 0 - 12 67 80
Waste to recycle 0 - 0 32,500 32,500
Wood waste 0 - 0 6,370 6,370
Wood pallets to
recycling
0 - 0 812,700 812,700
Table 24B. Generation of solid waste (in milligrams) resulting from the COMPOSTABLE
PLASTIC bag LCA. Based on consumer use & collection of 1500 bags. Totals may not agree
because of rounding.
Solid waste (mg) Fuel prod’n Fuel use Transport Process Total
Construction waste 0 - 0 0 0
Inert chemical 0 - 0 6 6
Metals 0 - 0 1,230 1,230
Mineral waste 1,660 - 39,800 608,000 649,000
Mixed industrial -19,200 - 1,650 3,940 -13,600
Municipal solid waste -195,000 - - 308,000 113,000
Paper 0 - 0 0 0
Plastic containers 0 - 0 - 0
Plastics 0 - 0 2,380 2,380
Putrescibles 0 - 11 <1 11
Regulated chemicals 27,600 - 7,250 199 35,100
Slags/ash 462,000 985 15,500 4,035,000 4,510,000
Tailings 40 - 23,900 427 24,400
Unregulated chemicals 20,900 - 52 124,000 145,000
Unspecified refuse 22,600 - 0 258,000 280,000
Waste returned to mine 1,097,000 - 1,470 162 1,098,000
Waste to compost - - - 38,000 38,000
Waste to incinerator 0 - 18 101 120
Waste to recycle 0 - 0 48,800 48,800
Wood waste 0 - 0 9,550 9,550
Wood pallets to
recycling
0 - 0 1,220,000 1,220,000
BCAL 41 LCA Grocery Bags
Final Disposal Solid Waste Options: Recycling, Combustion with Energy Recovery,
Landfill and Composting
Recycling
A major goal of recycling is to reduce the generation of solid waste. The bag making
process for grocery bags generates paper and plastic waste. The majority of this waste,
known as mill waste, is recycled internally. Therefore, in this study BCAL treated mill
waste as a closed loop recycling effort that returned the waste to the production process.
All of the grocery bags are recyclable to other paper and plastic products. EPA data from
2005 show that 21% of the kraft paper grocery bags are recycled and 5.2 % of the plastic
grocery bags are recycled. The allocation decision for these recycled materials is that the
recycled materials are not burdened with any inputs or outputs associated with their
previous manufacture, use, disposal prior to recycling.
BCAL used this allocation approach, and treated the recycled materials as diverted waste.
Diverted waste, like raw materials, are burdened with their intrinsic feedstock value and
are subsequently burdened with the resource use, energy consumption, and environmental
releases associated with their collection, cleaning and reprocessing, use, and disposal.
Therefore, the inherent feedstock energy value of the recycled material is assigned to the
diverted waste.
With respect to the degradable plastic bags, BCAL assumed that initially the same rate
that applies to recycling of standard plastic bags (5.2%) would be appropriate for the rate
sent to composting. This reflects a conservative approach using only data that currently
reflect consumer behavior with regard to plastic bags. It is expected that the percentage of
degradable plastic bags sent to composting will actually be higher once they are made
available and collection can occur within municipalities, making it easier for the general
consumer to send these bags through a different route of disposal. Recycling of plastic
bags is currently low. This may be for a number of reasons, not the least of which appears
to be the lack of infrastructure and poor consumer awareness about the inherent
recycleability of plastic bags.
Solid Waste Combustion With Energy Recovery
In previous years, a controlled burning process called combustion or incineration was
used solely to reduce volume of solid waste. However, energy recovery became more
prevalent in the 1980s. Therefore, today, most of the municipal solid waste combustion in
the US incorporates recovery of energy. EPA data from 2005 show that 13.6% of MSW
was combusted with energy recovery.
The gross calorific values for the various grocery bags are estimated as follows:
For kraft paper bags 17.7 MJ/kg
For recyclable plastic bag 40.0 MJ//kg
For degradable plastic bag 19.6 MJ/kg
BCAL 42 LCA Grocery Bags
These materials are used as fuels in the waste to energy plants, however the thermal
efficiencies for mass-burn WTE plants varies from 15% to 23% in the newer plants.6 This
study used 23% thermal efficiency for energy recovery.
Assuming complete combustion, the resulting estimated CO2 emissions are:
For kraft paper bags 1,650,000 mg/kg paper bag
For recyclable plastic bags 3,150,000 mg/kg recyclable plastic bag
For degradable plastic bags 1,360,000 mg/kg degradable plastic bag
The recovered energy (23% thermal efficiency) is as follows:
For kraft paper bags 4.07 MJ/kg paper bag
For recyclable plastic bags 9.20 MJ/kg recyclable plastic bag
For degradable plastic bags 4.51 MJ/kg degradable plastic bag
Therefore, using the above information, the following table is prepared on the basis of
1000 grocery bags and shows the recovered energy and resulting carbon dioxide
emissions when 13.6% of the 1000 grocery bags are combusted with energy recovery.
Table 25. Recovered energy (MJ) and resulting carbon dioxide emissions (mg) when
13.6% of the 1000 grocery bags are combusted with energy recovery.
Kraft Paper Bag Recyclable Plastic
Bag
Degradable Plastic
Bag
Recovered energy 28.7 MJ 7.2 MJ 9.7 MJ
CO2 emissions 11,640,000 mg 2,150,000 mg 2,920,000 mg
Table 25 shows that the kraft paper bag has the highest recovered energy and the highest
CO2 emissions. The recyclable and compostable plastic bags have significantly lower
recovered energy and CO2 emissions.
Solid Waste to Landfill
A landfill has various phases of decomposition. Initially, aerobic decomposition will take
place where oxygen is consumed to produce carbon dioxide gas and other by-products.
During the first phase of anaerobic decomposition, carbon dioxide is the principal gas
generated. As anaerobic decomposition proceeds toward the second phase, the quantity of
methane generated increases until the methane concentration reaches 50% to 60%. The
landfill will continue to generate methane at these concentrations for 10 or 20 years, and
possibly longer7.
Methane emissions from landfills in the United States were estimated at 8.0 million
metric tons in 2001. In addition, 2.5 million tons were recovered for energy use and 2.4
million tons were recovered and flared. Therefore, more than 60% of the methane
produced in landfills is not recovered.8
BCAL 43 LCA Grocery Bags
The precise fate of paper deposited in a landfill site is unknown. Paper may decompose
entirely in a short space of time or it may remain intact for long periods.9 This depends
on a variety of factors such as temperature, pH, the presence of bacteria and nutrients, the
composition of the waste and the form of the paper-shredded paper is much more likely
to decompose than is a whole telephone book. To account for this variability, two
scenarios were used to calculate emissions associated with the disposal of paper bags
(both adjustment for 40% of the recovered methane noted above). The first scenario is a
worst-case scenario that follows the basic decomposition reaction for cellulose and the
second scenario is one that estimates carbon sequestration for paper in MSW landfills.
Scenario 1 for Paper Bags
The basic decomposition reaction for cellulose is well known and follows the form of:
C6H10O5 + H2O = 3CH4 + 3CO2 (1)
It is therefore expected that only one half of the carbon present in kraft paper bags will
result in methane formation during decomposition. Typically carbon represents 45% of
the mass of paper. Thus, the carbon content of 1 kg of paper will be 0.45 kg. That
proportion giving rise to methane, assuming 100 % decomposition, would then be 0.225
kg. Based on this, the mass of methane produced would be 0.30 kg and the corresponding
mass of the coproduct carbon dioxide would be 0.83 kg.
Scenario 2 for Paper Bags
Although cellulose decomposition in landfill is well documented, there remains
significant uncertainty in the maximum extent of cellulose decomposition that can be
realized under landfill conditions. Several studies indicate that significant carbon
sequestration occurs in landfills because of the limited degradation of wood products. In
one study10 a carbon storage factor (CSF) was calculated that represented the mass of
carbon stored (not degraded) per initial carbon mass of the component. For the following
MSW paper refuse components the CSF was calculated: old newsprint = 0.42 kg C
sequestered, coated paper = 0.34 kg C sequestered, and old corrugated = 0.26 kg C
sequestered.
For this scenario the partial decomposition that the paper bags go through is assumed to
be aerobic or the initial anaerobic phase, resulting principally in carbon dioxide
emissions. In this scenario, we have assumed that the paper bags are similar to old
corrugated, and therefore have assigned the same value of 0.26 kg C sequestered. Given
that 0.26 kg of the kraft paper bag is assumed to be sequestered, 0.74 kg of the kraft
paper bag results in carbon dioxide emissions of 1.23 kg.
Recyclable plastic bags are not considered to degrade in landfills, suggesting that all the
inherent feedstock energy and emissions will be sequestered. Therefore, there are no
carbon dioxide or methane emissions associated with the recyclable plastic bags sent to
landfills.
BCAL 44 LCA Grocery Bags
Many types of biodegradable polymers are available to degrade in a variety of
environments, including soil, air, or compost. The biodegradable products degrade under
aerobic conditions to carbon dioxide and water in the presence of oxygen. The
biodegradable, compostable plastic bags in this study are made from a blend of Ecoflex
and PLA. Ecoflex is made from aliphatic-aromatic copolyester blended with equal
amounts of starch. According to information provided by BASF, Ecoflex meets the
requirements for biodegradable polymer classification based on European, US, and
Japanese standards because Ecoflex can be degraded by micro-organisms.11 PLA is a
biodegradable polymer made from corn and is converted completely to carbon dioxide
and water by micro-organisms. In addition, compostable plastic bags have been found to
degrade as designed within an allowable timeframe in appropriate composting facilities13.
In composting facilities, decomposition of biodegradable plastic bags made from a blend
of Ecoflex and PLA are expected to release primarily carbon dioxide emissions and
water. However, if sent to a landfill, biodegradable plastic will either not degrade at all,
or may follow similar pathways as paper bags (a combination of both aerobic and
anaerobic degradation). BCAL treated these bags in both ways in this study to examine
all possibilities.
Solid Waste Composting
The biodegradable, compostable plastic bags in this study have demonstrated
biodegradation in several standardized tests in several countries. Ecoflex and PLA meet
US, European, Australian, and Japanese standards by degrading in 12 weeks under
aerobic conditions in a compost environment and by breaking down to carbon dioxide
and water. The extent of the degradation for Ecoflex was 2 to 6 months in compost
depending upon temperature, and for PLA was 1 to 3 months in compost depending upon
temperature. 11 Therefore, in the composting environment, decomposition of
biodegradable plastic bags made from a blend of Ecoflex and PLA is expected to degrade
over time with the release primarily of carbon dioxide emissions and water.
LCA Calculations of Environmental Impacts
As noted under the section on LCA methodology, life cycle assessment modeling allows
an examination of specific problems as well as comparisons to determine if there are any
serious side effects to any of the systems under study. In every system there are multiple
environmental parameters to be addressed scaling from global to local issues, and no
single solution is likely to address all of the issues simultaneously. In addition, almost
every change to a system creates trade-offs, and it is the identification of these trade-offs
that is important when trying to determine the best solution for any given problem.
To reiterate, a life cycle assessment can:
1. Quantify those parameters likely to be responsible for environmental effects (the
inventory component of life cycle analysis).
2. Identify which parameters are likely to contribute to a specific environmental
problem (characterization or interpretation phase of impact assessment). An
BCAL 45 LCA Grocery Bags
example would be identifying that carbon dioxide (CO2), methane (CH4), and
nitrous oxide (N2O) are greenhouse gases.
3. Aggregate the parameters relating to a specific problem (the valuation or
interpretation phase of impact assessment). An example would be producing
carbon dioxide equivalents for the components of greenhouse gases.
The LCA calculations provide a compilation of information from which the user can
address specific problems such as the conservation of fossil fuels, global warming, acid
rain, and municipal solid waste. In addition, the user also is able to determine what trade-
offs exist between systems and to examine the specific parameters which are likely to
contribute to these problems. In so doing, the user can strive to achieve the optimum
reduction in each parameter because of a better understanding of how these parameters
change in association with each grocery bag system.
GLOBAL WARMING
One important issue that is currently being addressed using LCA studies is an
examination of the contribution that industrial systems make to climate change. The work
of the Intergovernmental Panel on Climate Change (IPCC)12 provides a framework for
aggregating data on those air emissions that are thought to be significant contributors to
global warming. The aggregated effect of any system can be summarized as a parameter
known as Global Warming Potential (GWP) or carbon dioxide equivalent. Any gaseous
emission that is thought to contribute to global warming is assigned a value equal to the
equivalent amount of CO2 that would be needed to produce the same effect. Multiplying
each gaseous emission by its CO2 equivalent allows the separate effects of different
emissions to be summed to give an overall measure of global warming potentials.
The major greenhouse gases of importance in this eco-profile are carbon dioxide,
methane and nitrous oxide. The results tables provided previously (see Section on LCA
Results) showed the global warming impacts (with carbon dioxide equivalents) up to the
collection of the grocery bags.
The following table estimates the global warming impacts just from the collection and
disposal of the grocery bags.
As discussed previously, two scenarios will be considered for the kraft paper bags, the
first is a worst-case scenario that follows the basic decomposition reaction for cellulose
and the second scenario is one that estimates carbon sequestration for paper in MSW
landfills.
The recyclable plastic bags will not degrade in the landfill; all the inherent feedstock
energy and emissions will be sequestered. Therefore, there are no carbon dioxide
emissions from recyclable plastic bags in landfills.
BCAL 46 LCA Grocery Bags
In the landfill, decomposition of biodegradable plastic bags made from a blend of Ecoflex
and PLA is expected to degrade over time with the release primarily of carbon dioxide
emissions and water.
Table 26A. Greenhouse gas emissions. 20-year carbon dioxide equivalents (in
milligrams) resulting from the disposal of 1000 grocery bags.
Disposal
process
Paper bag
with “worst
case
scenario” of
methane
emissions
Paper bag
with
“sequestered
scenario” of
carbon
dioxide
emissions
Recyclable
plastic bag
Degradable
plastic bag
With 100%
aerobic
decomposition
in landfill
Degradable
plastic bag
with 50%
aerobic &
50%
anaerobic
decomposition
in landfill
(using the
same pathway
as described
for paper
bags)
Recycling 21%
recycled &
burden is
transferred
21%
recycled &
burden is
transferred
5.2%
recycled &
burden is
transferred
5.2% recycled
to composting
& burden is
transferred
5.2% recycled
to composting
BCAL 47 LCA Grocery Bags
Table 26B. Greenhouse gas emissions. 20-year carbon dioxide equivalents (in
milligrams) resulting from the disposal of 1000 kraft paper grocery bags and 1500
recyclable plastic and degradable plastic grocery bags.
Disposal
process
Paper bag
with “worst
case
scenario” of
methane
emissions
Paper bag
with
“sequestered
scenario” of
carbon
dioxide
emissions
Recyclable
plastic bag
Degradable
plastic bag
With 100%
aerobic
decomposition
in landfill
Degradable
plastic bag
with 50%
aerobic &
50%
anaerobic
decomposition
in landfill
Recycling 21%
recycled &
burden is
transferred
21%
recycled &
burden is
transferred
5.2%
recycled &
burden is
transferred
5.2% recycled
to composting
& burden is
transferred
5.2% recycled
to composting
& burden is
transferred
Incineration
with energy
recovery
13.6%
11,640,000 11,640,000 3,230,000 4,380,000 4,380,000
BCAL 48 LCA Grocery Bags
*It should be noted that these emissions include the “credit” when carbon dioxide was
absorbed during tree growing.
Table 27A shows that from all operations just prior to disposal, the resulting CO2
equivalents are more than 20% greater for the paper bag compared to the recyclable
plastic bag. From all operations just prior to disposal, the resulting CO2 equivalents for
the degradable plastic bag are the highest about 4 times greater than the recyclable plastic
bag.
Table 27B Carbon dioxide equivalents (in milligrams) resulting from all operations just
prior to the disposal of 1000 kraft paper grocery bags and 1500 recyclable plastic and
degradable plastic grocery bags.
Recyclable and
Recycled Paper bag*
(from Table 6B)
Recyclable plastic
bag
(from Table 14B)
Degradable plastic
bag
(from Table 22B)
20 year CO2 eq. 23,710,000 mg 28,800,000 mg 134,000,000 mg
*It should be noted that these emissions include the “credit” when carbon dioxide was
absorbed during tree growing.
Table 27B shows that from all operations just prior to disposal, the resulting CO2
equivalents are more than 20% greater for the recyclable plastic bag compared to the
paper bag. From all operations just prior to disposal, the resulting CO2 equivalents for the
degradable plastic bag are the highest about 4 times greater than the recyclable plastic
bag and 5 times greater than the paper bag.
Now, adding the greenhouse gas emissions from tables 26 and 27 the total LCA cradle-
to-grave greenhouse gas emissions for the production, use, and disposal of 1000 grocery
bags are given in Table 28.
BCAL 49 LCA Grocery Bags
Table 28A. Total LCA cradle-to-grave CO2 equivalents (in milligrams) for the
production, use, and disposal of 1000 grocery bags:
Paper bag
with “worst-
case
scenario” of
methane
emissions
Paper bag with
“sequestered
scenario” of
carbon dioxide
emissions
Recyclable
plastic bag
Degradable
plastic bag
With 100%
aerobic
decomposition
in landfill
Degradable
plastic bag
with 50%
aerobic &
50%
anaerobic
decomposition
in landfill
20 year
CO2
eq
447,350,000 76,650,000 21,350,000 109,300,000 221,300,000
100
year
CO2
eq
202,200,000 65,490,000 18,850,000 99,300,000 134,800,000
500
year
CO2
eq
90,410,000 60,910,000 17,850,000 87,320,000 92,100,000
Table 28A shows that the recyclable plastic bag has the lowest the total cradle-to-grave
CO2 equivalents. The paper bag with the “sequestered scenario” has more than 3.5 times
the total cradle-to-grave CO2 equivalents of the recyclable plastic bag. The paper bag
with the “worst-case scenario” has more than 20 times the total cradle-to-grave CO2
equivalents of the recyclable plastic bag. The degradable plastic bag has more than 5
times the total cradle-to-grave CO2 equivalents of the recyclable plastic bag.
BCAL 50 LCA Grocery Bags
Table 28B. Total LCA cradle-to-grave CO2 equivalents (in milligrams) for the
production, use, and disposal of 1000 kraft paper grocery bags and 1500 recyclable
plastic and degradable plastic grocery bags.
Paper bag
with “worst-
case
scenario” of
methane
emissions
Paper bag with
“sequestered
scenario” of
carbon dioxide
emissions
Recyclable
plastic bag
Degradable
plastic bag
With 100%
aerobic
decomposition
in landfill
Degradable
plastic bag
with 50%
aerobic &
50%
anaerobic
decomposition
in landfill
20 year
CO2
eq
447,350,000 76,650,000 32,030,000 164,000,000 332,000,000
100
year
CO2
eq
202,200,000 65,490,000 28,300,000 149,000,000 202,000,000
500
year
CO2
eq
90,410,000 60,910,000 26,800,000 131,000,000 138,000,000
Table 28B shows that even using 1.5 plastic bags to 1 paper bag, the recyclable plastic
bag has the lowest the total cradle-to-grave CO2 equivalents. The paper bag, at a 1 to 1.5
use ratio, with the “sequestered scenario,” has about 2.3 times more total cradle-to-grave
CO2 equivalents of the recyclable plastic bag, depending upon the time horizon. The
paper bag with the “worst-case scenario” has more than 20 times the total cradle-to-grave
CO2 equivalents of the recyclable plastic bag. The degradable plastic bag has more than
5 times the total cradle-to-grave CO2 equivalents of the recyclable plastic bag.
STRATOSPHERIC OZONE DEPLETION
The stratospheric ozone layer occurs at an altitude of between 10-40 km. The maximum
generation of ozone (O3) occurs at the outer layer, where oxygen molecules (O2) react
with atomic oxygen. The presence of other compounds, particularly halogenated
compounds, promotes the decomposition of this ozone in the presence of strong ultra-
violet radiation.
In this study there were no identified ozone depleting chemicals associated with the bag
systems studied, and therefore no contributions to stratospheric ozone depletion.
BCAL 51 LCA Grocery Bags
products return from the atmosphere to the earth’s surface. The major source of acid rain
is the emission of these pollutants from coal powered electricity generating plants.
The following data were extracted from the results tables. There are no data available for
SOX and NOX emissions after disposal.
Table 29A. Acid rain emissions (in milligrams of SO2 and NO2) resulting from all
operations just prior to disposal 1000 grocery bags.
Acid rain emissions
mg
Paper bag Recyclable plastic
bag
Degradable plastic
bag
SOX 579,000 mg 50,500 mg 275,000 mg
NOX 264,000 mg 45,400 mg 304,000 mg
Table 29A shows that the recyclable plastic bag has the least SOX and NOX emissions.
The paper bag has more than 10 times the SOX emissions compared with the recyclable
plastic bag and more than 5 times the NOX emissions compared with the recyclable
plastic bag. The degradable plastic bag has more than 5 times the SOX and NOX
emissions compared with the recyclable plastic bag.
Table 29B. Acid rain emissions (in milligrams of SO2 and NO2) resulting from all
operations just prior to disposal for 1500 recyclable plastic bags and degradable plastic
grocery bags.
Acid rain emissions
mg
Paper bag Recyclable plastic
bag
Degradable plastic
bag
SOX 579,000 mg 75,800 mg 413,000 mg
NOX 264,000 mg 68,100 mg 456,000 mg
Table 29B shows that even using 1.5 plastic bags to 1 paper bag, the recyclable plastic
bag has the least SOX and NOX emissions. The paper bag, at a 1 to 1.5 use ratio, has
more than 7 times the SOX emissions compared with the recyclable plastic bag and
almost 4 times the NOX emissions compared with the recyclable plastic bag. The
degradable plastic bag has more than 5 times the SOX and NOX emissions compared
with the recyclable plastic bag.
MUNICIPAL SOLID WASTE
Another widespread environmental issue concerns the generation and disposal of
municipal solid waste. The mineral wastes from mining, the slags and ash wastes from oil
and gas production and utility coal combustion, and regulated chemical wastes are
generally managed by regulation and permits that exclude these wastes from the
municipal solid waste stream. The type of wastes in mixed industrial wastes can
contribute to the municipal solid waste problem. If, as in this study, there is an interest in
focusing on the municipal solid waste problem, the results on mineral wastes, slags &
ash, and regulated chemicals can be ignored. Selecting only the solid waste resulting
from just the disposal of grocery bags in landfill, one can prepare the following table 30A
considering disposal of 1000 grocery bags and table 30B considering disposal of 1000
BCAL 52 LCA Grocery Bags
kraft paper grocery bags and 1500 recyclable plastic and degradable plastic grocery bags.
The table reflects the waste that is landfilled as 65.4% paper bags and 81.2% plastic bags.
Table 30A. The municipal solid waste (in mg) resulting from just the disposal of grocery
bags in landfill. Based on 1000 grocery bags but only 65.4% of paper bags are landfilled
and 81.2% of plastic bags are landfilled.
Paper bag Recyclable plastic
bag
Degradable plastic
bag
Municipal solid
waste mg
33,900,000 4,690,000 12,800,000
Table 30A shows that the recyclable plastic bag has the least municipal solid waste. The
paper bag has more than 7 times the municipal solid waste compared with the recyclable
plastic bag. The degradable plastic bag has almost 3 times the municipal solid waste
compared with the recyclable plastic bag.
Table 30B. The municipal solid waste (in mg) resulting from just the disposal of grocery
bags in landfill. Based on 1000 kraft paper grocery bags but only 65.4% of paper bags are
landfilled and 1500 plastic grocery bags of which 81.2% of plastic bags are landfilled.
Paper bag Recyclable plastic
bag
Degradable plastic
bag
Municipal solid
waste mg
33,900,000 7,035,000 19,200,000
Table 30B shows that even using 1.5 plastic bags to 1 paper bag, the recyclable plastic
bag has the least municipal solid waste. The paper bag, at a 1 to 1.5 use ratio, has almost
5 times the municipal solid waste compared with the recyclable plastic bag. The
degradable plastic bag has almost 3 times the municipal solid waste compared with the
recyclable plastic bag.
CONSERVATION OF FOSSIL FUELS
Conservation problems are concerned with the depletion and possible exhaustion of raw
materials and fuels. With continued use, the finite supply of raw materials, and especially
fossil fuels will one day be exhausted. The conservation of fossil fuels: coal, oil ,and
natural gas is an important global environmental issue. It is therefore important to ensure
that these resources are used with the maximum efficiency and the minimum of waste.
BCAL 53 LCA Grocery Bags
Table 31A. The gross fossil fuels and feedstocks, expressed as energy (MJ) required for
the production, use, and disposal of 1000 grocery bags.
Energy in MJ Paper bag Recyclable plastic
bag
Degradable plastic
bag
Coal 324 65 161
Oil 207 206 353
Gas 391 186 705
Totals 922 457 1,219
Table 31A shows that the recyclable plastic bag uses the least fossil fuels and feedstocks.
The paper bag uses more than 2 times the fossil fuels and feedstocks compared with the
recyclable plastic bag. The degradable plastic bag used more than 2 1/2 times the fossil
fuels and feedstocks compared with the recyclable plastic bag.
Table 31B. The gross fossil fuels and feedstocks, expressed as energy (MJ) required for
the production, use, and disposal of 1000 kraft paper grocery bags and 1500 recyclable
plastic and degradable plastic grocery bags.
Energy in MJ Paper bag Recyclable plastic
bag
Degradable plastic
bag
Coal 324 98 242
Oil 207 309 530
Gas 391 279 1,058
Totals 922 686 1,830
Table 31B shows that even using 1.5 plastic bags to 1 paper bag, the recyclable plastic
bag uses the least fossil fuels and feedstocks. The paper bag, at a 1 to 1.5 use ratio, uses
34% more fossil fuels and feedstocks compared with the recyclable plastic bag. The
degradable plastic bag used more than 2 1/2 times the fossil fuels and feedstocks
compared with the recyclable plastic bag.
LOCAL & REGIONAL GRID ELECTRICITY USE
The US recently has experienced severe problems related to its local and regional grid
electricity. Because of these recent “blackouts,” “brownouts,” and electricity
interruptions, the need for appropriate conservation measures can be argued.
Table 32A. The electrical energy (MJ) required for the production, use, and disposal of
1000 grocery bags.
Paper bag Recyclable plastic
bag
Degradable plastic
bag
Electrical energy
MJ
649 148 325
BCAL 54 LCA Grocery Bags
Table 32A shows that the recyclable plastic bag uses the least electrical energy. The
paper bag uses more than 4 times the electrical energy compared to the recyclable plastic
bag. The degradable plastic bag used more than 2 times the electrical energy compared
with the recyclable plastic bag.
Table 32B. The electrical energy (MJ) required for the production, use, and disposal of
1000 kraft paper grocery bags and 1500 recyclable plastic and degradable plastic grocery
bags.
Paper bag Recyclable plastic
bag
Degradable plastic
bag
Electrical energy
MJ
649 222 488
Table 32B shows that even using 1.5 plastic bags to 1 paper bag, the recyclable plastic
bag uses the least electrical energy. The paper bag, at a 1 to 1.5 use ratio, uses almost 3
times the electrical energy compared with the recyclable plastic bag. The degradable
plastic bag used more than 2 times the electrical energy compared with the recyclable
plastic bag.
WATER USE & PUBLIC SUPPLY
Parts of the US continue to be plagued by periodic drought conditions. During these
times, laws and regulations concerning water conservation are enforced. Since public
water supply issues have been identified as a problem, the following table has been
prepared to compare public water supply used for the production, use, and disposal of
1000 grocery bags.
Table 33A. Public water supply (in mg) used for the production, use, and disposal of
1000 grocery bags.
Paper bag Recyclable plastic
bag
Degradable plastic
bag
Public water supply
(in mg)
3,895,000,000 31,150,000 2,560,000,000
Table 33A shows that the recyclable plastic bag uses the least public water supply. The
paper bag uses more than 125 times the public water supply compared with the recyclable
plastic bag. The degradable plastic bag used more than 80 times the public water supply
compared with the recyclable plastic bag.
Table 33B. Public water supply (in mg) used for the production, use, and disposal of
1000 kraft paper grocery bags and 1500 recyclable plastic and degradable plastic grocery
bags.
Paper bag Recyclable plastic
bag
Degradable plastic
bag
Public water supply 3,895,000,000 46,700,000 3,840,000,000
BCAL 55 LCA Grocery Bags
(in mg)
Table 33B shows that even using 1.5 plastic bags to 1 paper bag, the recyclable plastic
bag uses the least public water supply. The paper bag, at a 1 to 1.5 use ratio, uses more
than 80 times the public water supply compared with the recyclable plastic bag. The
degradable plastic bag used more than 80 times the public water supply compared with
the recyclable plastic bag.
SUMMARY AND CONCLUSIONS
Recent efforts by legislators to ban traditional plastic bags on the basis of environmental
impact have reignited the debate surrounding single-use grocery bags, and whether there
are any environmental trade-offs in switching from bags made with polyethylene to bags
made from alternative materials.
This life cycle assessment was commissioned to examine the overall environmental
impacts associated with the typical single-use polyethylene plastic grocery bag, compared
with grocery bags made from compostable plastic resin and grocery bags made from 30%
recycled paper.
Life cycle assessment is a useful analytical tool because it allows for the examination of
an entire production system from cradle to grave, thus examining the full range (global,
regional, and local impacts) of environmental issues at once rather than examining
individual components of a system or individual products or processes. This broad
picture analysis is important because environmental effects range from global
(greenhouse gases), to regional (acid rain/solid waste) or local (toxic releases) impacts.
And while there often is excellent information on local environmental effects, few
complete data sets are available to understand the contributions production systems are
making to global and regional environmental problems.
These study results confirm that the standard polyethylene grocery bag has significantly
lower environmental impacts than a 30% recycled content paper bag. This supports
conclusions drawn from a number of other studies looking at similar systems.14, 15, 16 In
addition, this report also shows that the typical polyethylene grocery bag has fewer
environmental impacts than a compostable plastic grocery bag made from a blend of
EcoFlex (BASF), polylactic acid, and calcium carbonate, when compared on a 1:1 basis,
as well as when the number of bags is adjusted for carrying capacity so that the
comparison is 1.5:1. Surprisingly, the trend is the same for most of the individual
categories of environmental impacts. No one category showed environmental impacts
lower for either the compostable plastic bag or the paper bag.
This study did not examine the impacts associated with reusable cloth bags, so no
comparison was made between the cloth bags and single-use polyethylene plastic bags.
In other studies, however, cloth bags were shown to reduce environmental impacts if
consumers can be convinced to switch. The problem is that there are few examples where
entire cities, counties, or countries have been successful in changing consumer behavior
BCAL 56 LCA Grocery Bags
from the convenience of using bags provided by retail establishments to bringing their
own bags to the store each time they shop. There is no question that a percentage of
consumers do, and will use reusable cloth grocery bags, but the vast majority of
consumers still appear to use the freely available bags provided by retail establishments.
So, if consumer behaviors are not appearing to change, banning one type of single-use
bag will simply mean that it is replaced by another type of single-use bag.
Given the above-stated assumption, it is clear that the replacement bags will either be
compostable plastic bags or paper bags, as proposed legislation tends to stipulate these as
the preferred alternatives. But can these alternative materials meet the legislative
objectives, which often include: the reduction of litter, the need to reduce dependence on
fossil fuels, and the need to reduce solid wastes? Taking the latter two objectives first,
one can use the LCA results in this report to see if the above stated objectives are being
met.
In the case of reducing dependence on overall energy, it is clear (see Table 34) that
neither the life cycle of compostable bag nor paper bag provides a reduction in overall
energy use. The standard polyethylene plastic grocery bag uses between 1.8 and 3.4 times
less energy than the compostable and paper bag systems, respectively.
Table 34. Gross Energy by Activity (MJ)
Fuel prod’n
(total)
Fuel use
(total)
Transport
(total)
Feedstock
(total)
Total
Paper Bag
(1000 bags)
493 1105 34 991 2622
Compostable
Plastic Bag
(1000 bags)
265 659 38 418 1380
Compostable
Plastic Bag
(1500 bags)
398 988 57 627 2070
Polyethylene
Plastic Bag
(1000 bags)
106 114 11 279 509
Polyethylene
Plastic Bag
(1500 bags)
159 171 16 418 763
Table 35 demonstrates that in terms of fossil fuel use, including oil, the compostable
plastic bag system does not provide any benefit. The compostable plastic bag system
appears to use more oil than either of the other two bag systems, varying from 1.7 to 2.57
times more oil than either the plastic bag or paper bag systems, respectively. The paper
bag system would appear to be able to provide a slight improvement, but only if the
plastic bag system actually uses 1.5 bags for every 1 bag in the paper system. If this
assumption cannot be supported, then the paper bag system would not provide even a
slight advantage.
BCAL 57 LCA Grocery Bags
Table 35. Gross Fossil Fuel Use (kg)
Paper Bag
(1000
bags)
Compostable
Plastic Bag
(1000 bags)
Compostable
Plastic Bag
(1500 bags)
Polyethylene
Plastic Bag
(1000 bags)
Polyethylene
Plastic Bag
(1500 bags)
Coal 11.2 5.8 8.7 2.3 3.4
Oil 4.6 7.8 11.8 4.6 6.9
Gas 7.4 14.0 21.0 3.1 4.6
These results may appear to some to be counterintuitive, but both compostable plastic and
paper bags require more material per bag in their manufacture. This results in greater use
of fuels in the extraction and transport of raw materials for the manufacture of the bags,
as well as greater energy in bag manufacturing and greater fuel use in the transport of the
finished product from the manufacturer to retail establishments. Although standard
polyethylene plastic bags are made from oil, the added requirements of manufacturing
energy and transport for the compostable and paper bag systems far exceed the raw
material use in the standard plastic bag system.
The results of this study also show that the standard polyethylene single-use plastic
grocery bag’s contribution to the solid waste stream is far lower than either the paper bag
system or the compostable bag system. This is not surprising considering both the
compostable bag and paper bag systems require more material per bag. The increase in
solid wastes has become an important global issue as populations multiply and
developing countries become wealthier, consuming more material goods. Currently, more
land is being devoted to the disposing of solid wastes, and the lack of proper containment
in solid waste facilities is causing problems in terms of soil contamination and water
pollution.
BCAL 58 LCA Grocery Bags
Table 36. Municipal Solid Waste (kg)
Paper
Bag
(1000
bags)
Compostable
Plastic Bag
(1000 bags)
Compostable
Plastic Bag
(1500 bags)
Polyethylene
Plastic Bag
(1000 bags)
Polyethylene
Plastic Bag
(1500 bags)
33.9 12.8 19.2 4.7 7.0
This study was not designed to address the issue of litter, so no specific calculations were
conducted on the effect of the various bag systems on litter. However, there are some
interesting points that can be made with regard to meeting the objective of reducing litter
by switching to alternative materials in the grocery bag system. The summary of results
discussed above on energy use and solid waste already illustrate that reducing litter
through a change in the grocery bag system will lead to greater use in energy and greater
amounts of solid wastes. Those who believe that this is an acceptable trade-off must also
understand that there are additional, and perhaps far more serious, environmental impacts
that will result if plastic bags are supplanted by either compostable plastic bags or paper.
One of these serious environmental impacts is global warming. The study showed that
switching from single-use polyethylene plastic grocery bags to either paper or
compostable plastic grocery bags may increase the emission of greenhouse gases and
therefore contribute to global warming (See Table 37). Based on these results, it appears
that the trade-off for reducing litter is an increase in global warming, which if not curbed,
is expected to cause problems for decades and to affect marine, freshwater, and terrestrial
habitats, and species globally. If one of the major concerns about litter is its accumulation
in marine habitats and its negative effect on sea life, it would hardly seem justified to
address the effects of litter with a grocery bag system that can cause significant harm to
not only the same habitats, but to all other habitats as well.
BCAL 59 LCA Grocery Bags
Table 37. Global Warming Potential
(CO2 Equivalents in tons)
Paper bag
with
“sequestered
scenario” of
carbon
dioxide
emissions
(1000 bags)
Compostable
plastic bag
With 100%
aerobic
decomposition
in landfill
(1500 bags)
Compostable
plastic bag
with 50%
aerobic &
50%
anaerobic
decomposition
in landfill
(1500 bags)
Polyethylene
Plastic Bag
(1500 bags)
Production 0.03 0.15 0.15 0.03
Disposal 0.05 0.03 0.22 0.00
Total 0.08 0.18 0.37 0.04
Another increasingly important issue is the protection of water sources around the globe.
Concerns have been raised over the long-term availability of water to support the
expanding population’s need for drinking, manufacturing, and agriculture. Table 38
shows the use of freshwater resources for each of the grocery bag systems studied. The
standard polyethylene plastic bag uses significantly less water, compared with the paper
or compostable grocery bag systems. Paper grocery bags use approximately 1 gallon of
water for every bag, compared with the plastic bag system, which uses only .008 gallons
per bag or 1 gallon for every 116 bags. Compostable grocery bags do not appear to
provide any improvement over paper bags, and use far more water than the standard
polyethylene plastic bag. It appears, therefore, that in switching to a paper bag or
compostable plastic bag system to combat a litter problem, consumers will have to accept
another significant trade-off—the increase in use of valuable water resources.
Table 38. Gross Freshwater Resources (gallons)
Paper Bag
(1000
bags)
Compostable
Plastic Bag
(1000 bags)
Compostable
Plastic Bag
(1500 bags)
Polyethylene
Plastic Bag
(1000 bags)
Polyethylene
Plastic Bag
BCAL 60 LCA Grocery Bags
consider when making a decision on which systems to implement. Paper bag systems use
a completely different resource base—wood fiber—than the plastic bag system. If the
wood fiber does not come from sustainably managed forest systems or from agricultural
wastes, it may cause a trade-off that is unacceptable to consumers. Forests are important
ecosystems that support a wide variety of life, and disrupting these ecosystems in the
name of reducing litter is an effect that deserves further contemplation.
The study results support the conclusion that any decision to ban traditional polyethylene
plastic grocery bags in favor of bags made from alternative materials (compostable
plastic or recycled paper) will be counterproductive and result in a significant increase in
environmental impacts across a number of categories from global warming effects to the
use of precious potable water resources.
Addressing the issue of increasing litter with bans on plastic grocery bags may be
counterproductive as this study has not considered many other mitigating circumstances
that may lead to even greater differentials between plastic grocery bags and those made
from either paper or compostable plastics.
Increased recycling rates for plastic bags, better bagging techniques at retail, and
secondary uses of plastic grocery bags such as waste disposal could all further reduce the
environmental impacts of plastic grocery bags. In addition, getting consumers to change
their behavior so that plastic bags are kept out of the litter stream would appear to be
more productive in reducing the overall environmental impact of plastic bags including
litter.
This study supports the conclusion that the standard polyethylene grocery bag has
significantly lower environmental impacts than a 30% recycled content paper bag and a
compostable plastic bag. An LCA report and its findings can be used to demonstrate that
an environmental impact analysis needs to take into account the entire picture, and when
dealing with a product that is likely to be replaced by another, the trade-offs in the
environmental impact of the replaced alternative should also be given a critical analysis.
BCAL 61 LCA Grocery Bags
LITERATURE REFERENCES
1 Private communication between PBA member and Weyerhauser, June 2007.
2 Municipal Solid Waste in the USA: 2005 Facts & Figures, USEPA, Office of Solid
Waste, EPA530-R-06-011, October 2006.
3 Boustead, I. Eco-profiles of the European plastics industry: Report 3 – polyethylene
and polypropylene. A report for the European Centre for Plastics in the Environment
(PWMI), Brussels, May 1993. Revised 1999.
4 Private communications with BASF, Edwards, K. and Bradlee, C., May-July 2007.
5 Vink, E. T. H., Rabago, K. R., Glassner, D. A., Gruber, P. R, Applications of life cycle
assessment to NatureWorks TM polylactide (PLA) production. Polymer Degradation and
Stability 80 (2003) Elsevier, The Netherlands.
6 Stodolsky, F., and Mintz, M. .M, Energy Life-Cycle Analysis of Newspaper, Energy
Systems Division Argonne National Laboratory, Argonne, IL , May 1993.
7 Robinson, W. D., The Solid Waste Handbook, John Wiley & Sons, New York, 1986.
8Methane Emissions, Energy Information Administration/Emissions of Greenhouse
Gases in the United States 2001.
9Rathje, W., Excavating Landfills, Presentation at GRCDA 13’th Annual Landfill Gas
Symposium. Lincolnshire, IL, 1990.
10Barlaz, M. A. Carbon storage during biodegradation of municipal solid waste
components in laboratory scale landfills. Global Biochem. Cycles, 12(2):373-380, 1998.
11Evaluation of the Performance of Rigid Plastic Packaging Containers, Bags, and Food
Service Packaging in Full-Scale Commercial Composting, A report to the Integrated
Waste Management Board, California Environmental Protection Agency, Sacramento,
CA, March 2007
12Houghton, J. T., Meira Filho, L.G., Callander, B.A., Harris, N., Kattenberg, A. &
Maskell, K. (eds). Climate Change 1995 – Contribution of WGI to the Second
Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge
University Press, 1996.
13Evaluation of the Performance of Rigid Plastic Packaging Containers, Bags, and Food
Service Packaging in Full Scale Commercial Composting. California State University,
Chico Research Foundation. 2007. Prepared for the California Integrated Waste
Management Board under Contract IWM-C2061.
BCAL 62 LCA Grocery Bags
14 EPA of Polyethylene and Unbleached Paper Grocery Sacks, Prepared for the Solid
Waste Council, Franklin Associates Report, June 1990.
15 Life Cycle Inventory of Packaging Options For Shipment of Retail Mail-order Soft
Goods, Prepared For Oregon Dept. of Environmental Quality (DEQ) and
U.S. EPA Environmentally Preferable Purchasing Program, Franklin Associates,
2004.
16 Evaluation des impacts environnementaux des sacs de caisse Carrefour. Analyse du
cycle de vie de sacs decaisse en plastique, papier, et materriau biodegradable. Rapport
prepare pour Carrefour. Fevrier 2004.
REFERENCES REGARDING THE BOUSTEAD MODEL
1. Boustead, I., Boustead Model V5.0 Operating Manual, Boustead Consulting Ltd.,
2003.
2. Boustead, I., Boustead Model V5.0 Code Book & Conversion Factors,Boustead
Consulting Ltd., 2003.
3. Boustead, I., An Introduction to Life Cycle Assessment,Boustead Consulting Ltd.,
2003.
4. Boustead, I., The Boustead Model Information Book, pages 1 – 500, Boustead
Consulting Ltd.
BCAL 63 LCA Grocery Bags
APPENDIX 1 – PEER REVIEW
Background
Dr. Overcash conducted the peer review and is a Professor of Chemical Engineering, as
well as a Professor of Biological and Agricultural Engineering at North Carolina State
University. Dr. Overcash has developed an in-depth national research program in life
cycle research, developing the new areas for utilization of the life cycle tools. Dr.
Overcash has led the effort in life cycle inventory techniques for manufacturing
improvement and product change. Dr. Overcash has contributed to life cycle studies in
energy production, electroplating, solvent selection, pharmaceutical processes, life cycle
assessment comparisons, paper industry, and textiles. He has been active in European
life cycle efforts and reviews of research in this field.
All of the suggestions and recommendations made by Dr. Overcash have been reviewed
and incorporated in this report. Below is the Peer Review Report provided by Dr.
Overcash.
Review of Draft Report
Life cycle assessment for three types of grocery bags – recyclable plastic; compostable,
biodegradable plastic; and recycled, recyclable paper
By Dr. Michael Overcash
September 2, 2007
This report provides both a sound technical descriptions of the grocery bag products and
the processes of life cycle use. The functional unit has a range to accommodate
differences in customer use found to exist. These differences did not prove to change the
resulting low environmental impact choice. The discussion of the limitations of the life
cycle impact assessment is very important and the readers should use these observations.
The following detailed review is divided into technical and editorial segments.
The conclusions regarding the relative environmental impact when using a life cycle view
are consistent with previous studies and need to be reinforced in the policy arena. The
policies to discourage plastic bags may have more to do with litter than the overall
environment. Whatever the goals of the policy makers, these need to be far more explicit
than general environmental improvement, since the life cycle story is consistent in favor
of recyclable plastic bags. It is possible that the emphasis of another report might be that
the full benefit of plastic bags is even higher when large recycling is in place.
Technical
1) p.3 last paragraph BBL is not defined
2) Table 3 at 5.78 kg functional unit this mass reflects the 50% water in wood.
However this wood is lignin and cellulose and so only about 50% of the solid
material ends up in paper bag, so this should be 274,000,000 mg
BCAL 64 LCA Grocery Bags
3) Table 5 These occur in all the raw material Tables
a. Biomass is double counted as it appears also in Table 3 while wood
does not appear both places
b. Limestone is listed twice, here and as chalk
c. N2 and O2 are listed twice as air and constituents of air
4) Table 7 This is an unusually high COD:BOD ratio, it might need to be checked
5) Table 9B Elec = 103 This did not change from Table 9A, while all the other
values did change reflecting the differences in number of bags.
6) p.34 line 4 under Solid Waste This identifies steam or electricity as possible
energy recovery mechanisms, but Table 25 is only electricity. Steam would have
a much higher recovery value
7) p.41 2nd line From the data in Table 28A this ratio is more like 3.5 and
not 2.5
8) p. 42 3rd line From the data in Table 28B it is hard to see any ratio as high as 13
Editorial
1) p1 2nd line world for governments
2) p4 last para, 3rd line represent
3) whole document the conventional style is that data are plural, but throughout
this documents that is mostly not followed. A search for the word data and
inserting the correct verb will fix this.
(1500 bags)
Public
Supply 1000 660 1000 8 13
Other 4 12 17 32 45
Other environmental factors that show similar trends are the emission of acid rain gases
and water pollutants. In both cases, paper bag and compostable bag systems show larger
amounts of pollutants emitted into the environment than those emitted by the plastic
grocery bag system. Similarly, there are other environmental matters that are important to
ACID RAIN
The production of acid rain in the northeastern United States is recognized as a regional
problem. Acid rain results when sulfur and nitrogen oxides and their transformation
Landfill
65.4%
paper,
81.2%
plastic
412,000,000 41,300,000 0 26,100,000 194,000,000
Total
disposal
related
emissions
423,640,000 52,940,000 3,230,000 30,500,000 198,000,000
Table 26B shows that even using 1.5 plastic bags to 1 paper bag, after disposal, the
recyclable plastic bag has the lowest greenhouse gas emissions. The paper bag at a 1 to
1.5 use ratio, with the “sequestered scenario,” has more than 10 times the greenhouse gas
emissions of the recyclable plastic bag. The paper bag with the “worst-case scenario” has
more than 130 times the greenhouse gas emissions of the recyclable plastic bag. The
degradable plastic bag has more than 9 times the greenhouse gas emissions of the
recyclable plastic bag with the 100% aerobic decomposition and more than 60 times the
greenhouse gas emissions of the recyclable plastic bag with the 50% aerobic
decomposition/50% anaerobic decomposition.
Table 27A. Carbon dioxide equivalents (in milligrams) resulting from all operations just
prior to the disposal of 1000 grocery bags.
Recyclable and
Recycled Paper bag*
(from Table 6B)
Recyclable plastic
bag
(from Table 14B)
Degradable plastic
bag
(from Table 22B)
20 year CO2 eq. 23,710,000 mg 19,200,000 mg 89,000,000 mg
& burden is
transferred
Incineration
with energy
recovery
13.6%
11,640,000 11,640,000 2,150,000 2,920,000 2,920,000
Landfill
65.4%
paper,
81.2%
plastic
412,000,000 41,300,000 0 17,400,000 129,400,000
Total
disposal
related
emissions
423,640,000 52,940,000 2,150,000 20,320,000 132,320,000
Table 26A shows that after disposal, the recyclable plastic bag has the lowest greenhouse
gas emissions. The paper bag with the “sequestered scenario” has more than 15 times the
greenhouse gas emissions of the recyclable plastic bag. The paper bag with the “worst-
case scenario” has more than 200 times the greenhouse gas emissions of the recyclable
plastic bag. The degradable plastic bag has more than 9 times the greenhouse gas
emissions of the recyclable plastic bag.
Wind 0 11 0 - 11
Totals 265 659 38 418 1,380