Executive summary of Xiaoqian Shangguan's MSc thesis - Imperial ...

Executive summary of Xiaoqian Shangguan’s MSc thesis
Life Cycle Assessment of the environmental impact of wheat straw based
packaging material, as used for strawberry punnets
By Xiaoqian Shangguan
Centre for Environmental Policy
Faculty of Natural Science
Imperial college London
Academic year: 2008-2009
Supervisors: Dr. Richard Murphy and Prof. Nigel Bell
Objectives:
This LCA will examine the use of wheat straw in a manufacturing process that will lead to
the formation of a strawberry punnet. The objectives were thus a follows:
1. To establish a life cycle inventory for the emissions, material and energy
consumptions for the sourcing, manufacture and disposal of a bio-based packaging
material.
2. To identify sources of environmental impact in the whole life cycle of a bio-based
packaging material, and benchmark this eco-profile against that for a conventional
petrochemical-based polymer(s) (APET).
3. To identify areas in the LCA profile of bio-based packaging that have promise for
reductions in the overall environmental impact e.g. location of sites of production and
distribution.
Introduction:
This project section summarises the drives for switching to bio-degradable packaging from
conventional packaging. The first part outlines the importance of packaging and the criteria
of good packaging. This is then followed by a summary on EU and UK legislations, in which
the UK Directive 94/62/EC on packaging and packaging waste is implemented by the
Producer Responsibility Obligations and the Essential Requirements Regulations.
The Landfill Directive requires that, the amount of biodegradable municipal waste reduce to
35% of the 1995 level by 2020. Meanwhile, Defra has set a recovery and recycling target of
74% in 2010 for packaging waste in the UK. To reduce the amount of packaging waste that
goes to landfill, organisations such as the Alternative Crops Technology Interaction Network

(ACTIN) and the UK Government-Industry Forum have being encouraging the use of
biodegradable packaging.
The current position on bio-packaging was then introduced. The main limitations for utilising
bio-based packaging are the high cost and limited available resources. Wheat straw is
therefore a suitable resource for packaging manufacturing, since it is an abundant by-product
from the UK farms and hence is of comparatively low cost. The current uses of straw include
animal bedding, animal feeding, soil conditioner and as feed stock for energy generation. The
biological composition of straw was next explained, with particular reference to lignin and
hemi-cellulose, which can have impact on the pulping process. The current waste options
available for bio-degradable packaging include landfill, incineration, industrial anaerobic
digestion and home composting.
The summary of the whole life cycle of wheat straw based packaging material was then
stated. The process includes raw material acquisition, transportation of the raw material to
manufacturing site, manufacturing, drying, use and disposal.
Methodology:
The research methodology used in this project included literature review and data collection,
before data processing and analysis with SimaPro 6.0 software.
The information regarding EU and UK legislations stated in the background sections are
mainly drawn from the Department of Food and Rural Affairs (Defra), as well as the
European Commission websites. The scientific and technological information were obtained
from journals, books, academic theses and government reports.
Primary data was collected from farm visits, company meetings and sending questionnaires
to consortium partners and suppliers; the farm questionnaire was constructed to collect
information regarding wheat cultivation. Site specific data were collected from the
consortium companies and Bangor University regarding the technical development of various
bio-based materials.
The LCA was done concisely according to the ISO 14040 standard. SimaPro 6.0 software
was the data analysis tool as well as a secondary data source of the LCA for this product. It
provides detailed information regarding materials involved, energy consumed and emissions
from the processes etc. The databases used in this study were the Ecoinvent database and
BUWAL 250 database.
Results:
Section 2 shows how the LCA was conducted. The whole LCA consisted of four phases:
1. Goal and Scope
2. Inventory analysis
3. Impact assessment
4. Interpretation

The nature of each phase was briefly explained, followed by the actual conduction of each
stage based on the life stages of the product.
Several scenarios were used to compare and contrast how differences in each life stage of the
product can have different impacts on the environment. The scenarios were constructed based
on the location of the manufacturing factory proposed, the drying method used, and the waste
treatment used.
Data on chemical input, fuel consumption, energy input and waste treatment were entered
into SimaPro, and the environmental impacts of each scenario shown in terms of nine impact
categories: abiotic depletion, global warming, ozone layer depletion, human toxicity, fresh
water aquatic toxicity, terrestrial toxicity, photochemical oxidation, acidification and
eutrophication.
The results show that the impacts level reduced considerably when the drying efficiency was
improved, in every scenario. The sensitivity analysis showed that by reducing the drying
energy to 70% of the present level, the FarmPULP punnets would have an eco-profile that is
better in every category in comparison with the conventional APET punnets. The waste
treatment option also affects the level of impact considerably. In general, Landfill gives
highest emissions and home composting lowest, however these results could be skewed by
differing energy usages occurring in the different drying processes of each method.
Discussion, Conclusions and implications:
This study was in fact a scoping LCA, hence the results will be used to improve the
development of the product and has given a variety of options in which the product could be
developed in an economically viable and sustainable way. However, it has also revealed
some potential limitations of bio-degradable packaging.
For bio-degradable packing to be accepted as an equivalent material to plastic packaging
however, its manufacture has to be financially viable. Secondly, it has to have an eco-profile
that is better than that of plastic packaging, over its entire life cycle. Any significant adverse
impact in any life stage of the biodegradable packaging will trigger the miscarriage of the
development of the product. In the case of this study, it has been established that the
strawberry punnet cannot contain toxic chemicals, and has to be fully compostable within six
months. These issues of toxicity and compostability however limit the selection of the
pulping process. Thus, mechanical pulping is a preferred technique, as although it consumes
more energy than processes such as enzyme pulping, the product produced by this method is
non-toxic. In addition, biodegradable packaging must fulfil the criteria of ‘good packaging’.
In summary, this study has shown that, based on current technologies used, the wheat straw
based strawberry punnet has a better eco-profile than the conventional plastic punnet overall.
What’s more, based on the assumptions used in this study, the location of manufacturing
would not have a significant impact on the overall environmental performance of the punnet.