Eco-functional assessment of grocery shopping bags

Pao Yue-kong Library Electronic Theses Database

Eco-functional assessment of grocery shopping bags

 

Author: Muthu, Subramanian Senthilkannan
Title: Eco-functional assessment of grocery shopping bags
Degree: Ph.D.
Year: 2012
Subject: Shopping bags -- Environmental aspects.
Hong Kong Polytechnic University -- Dissertations
Department: Institute of Textiles and Clothing
Pages: xxix, 370 p. : ill. (some col.) ; 30 cm.
Language: English
InnoPac Record: http://library.polyu.edu.hk/record=b2522689
URI: http://theses.lib.polyu.edu.hk/handle/200/6588
Abstract: In this environmentally conscious era, the environmental implications of any product, including textile products, are of pivotal significance. Decisions on the life of textile products are determined by the functional properties of products, which will in turn govern their ecological properties in most instances. These interlinked factors go hand in hand and very importantly they govern consumer behaviour. Functional and ecological properties combined with consumer behaviour are the key aspects influencing the implications for the environment of a product. Functional, ecological properties and consumer behaviour are currently treated as individual issues by consumers, business people and also industry. In fact, they are interrelated and also interactive with each other; their interaction is at the heart of this research. To date, no systematic study has been reported in the literature addressing the interrelation and interaction of these aspects. This study makes an attempt to combine these aspects in a single platform termed "Eco-Functional Assessment". This research discusses the concept of eco-functional assessment and demonstrates the applications of the concept by considering shopping bags used for grocery purposes as an example. Knowledge gaps were identified by a systematic and extensive literature review in the areas pertaining to eco-functional assessment and shopping bags, specifically. The primary aim of this research is to fill the knowledge gaps by establishing a theoretical framework of eco-functional assessment, which has not been reported in the literature to date. An eco-functional assessment model was developed with four inputs (raw materials, process of manufacture, functional properties and ecological properties) and five outputs (quality, functionality, 3Rs, human impact and environmental impact). These inputs and outputs and their interrelation can provide a profile of the essential characteristics for the eco-functional assessment of any textile product. An eco-functional assessment combined with the life cycle assessment (LCA) study was also conducted to assess the influence of functional, ecological properties and consumer behaviour on carbon footprint, ecological footprint and eco-damage throughout the life cycle of various shopping bags. Research questions were formulated to identify the contribution of each phase in the life cycle to the final life cycle impact of the shopping bags. Beginning from raw material, since no approach or model has been reported for the quantification of various textile fibres and raw materials used for shopping bags in terms of their environmental impact and ecological sustainability, a model was created to evaluate and quantify the environmental impact index (EI) and ecological sustainability index (ESI) of different textile fibres and other raw materials used for shopping bags. From the developed model, it was found that organic cotton is the most and acrylic the least sustainable fibre. For the process of manufacture, it is worthwhile to conduct a life cycle audit to develop a comprehensive life cycle inventory of the manufacturing process of a product from the cradle to gate stage. This research demonstrates an approach to conduct a life cycle audit in a factory that manufactures a range of nonwoven shopping bags to obtain the primary data for the production processes of different types of nonwoven bags. Life cycle impacts of the manufacturing phase of various shopping bags were quantified by characterizing and normalizing the impacts pertaining to consumers living in Mainland China. The manual calculation results were verified with the commercial software, SIMAPRO version 7.2. For functional properties, a comprehensive list was drawn up and evaluated in this study. With regard to shopping bags, there are some properties which lie at the interface of functional and ecological properties, which I term here the "Eco-functional properties" of shopping bags. They are: reusability, impact strength and weight-holding capacity. Currently, there are no instruments available to evaluate these properties scientifically. Hence in this research, a new instrument termed "Eco-functional Tester" was developed to quantify these properties in various shopping bags. From the experimentation results, it was clear that reusable bags made out of cotton exhibited better results in terms of eco-functional properties.
In the disposal phase of shopping bags/textile products, recyclability is one of the primary factors that need to be considered in evaluating the eco-impact. There are no models or approaches to quantify the recyclability potential of various textile fibres and raw materials used for shopping bags in terms of their environmental and economic gains. An attempt was made in this research to develop a model to quantify the recyclability potential index (RPI) of various textile fibres and raw materials used for shopping bags. Results of the RPI model indicate that polypropylene and polyester outscored all the other materials in question. Apart from reusability and recyclability, biodegradability is also an important focus in the ecological category. This research employed the results of a biodegradability test conducted for various shopping bags on the same platform using the soil burial test. Soil burial test results showed that paper bags followed by cotton bags demonstrated better biodegradation results. Regarding consumption behaviour, the perceptions or opinions of consumers have to be taken into consideration to make the end-of-life scenario values in the life cycle assessment calculations rather than using assumptions of the usage and disposal values. LCA studies reported to date on various shopping bags have used an assumption to model the end-of-life scenarios of various shopping bags, but this may not reflect reality. Hence a questionnaire survey was conducted in this research among different user groups in Mainland China, Hong Kong and India and the results from the real users were utilized to model the end-of-life phase of the various shopping bags. With the aid of the eco-functional model where the values from the discussed aspects are synthesized, eco-functional capacities of any product can be assessed and an "eco-functional" score can be assigned to any product. 23 samples made out of different types of shopping bags were assessed in terms of their eco-functional properties and the eco-functional score of each bag was evaluated and the results are presented. The results of the eco-functional assessment reveal the importance of every aspect of a product to meet the requirements of eco-functional assessment. For the eco-functional assessment combined with LCA study various shopping bags, a suitable functional unit based on consumption statistics from Mainland China, Hong Kong and India was earmarked for this LCA study. Detailed life cycle inventory details were collected for various life cycle phases of different types of shopping bags. Carbon footprint, ecological footprint and eco-damage assessments were made to quantify the life cycle impacts of each phase of the various shopping bags with the aid of SIMAPRO version 7.3 of LCA software. The LCA results revealed that each phase of life cycle impacted the final result and the reusable bags outscored single use bags in all three territories. Nonwoven bags made out of polypropylene followed by polyester and woven cotton bags caused fewer life cycle impacts. LDPE bags were shown to create higher impacts in the list of samples chosen for this study. Also the life cycle impacts of shopping bags used by an average Indian were found to be less compared to those for Chinese and Hong Kong residents. It was also apparent from the LCA results that the greater degree of reuse selected, the less the carbon footprint, ecological footprint and eco-damage in all the three territories. Even a small contribution from the consumer's side, to reuse a bag one more time, would make a great difference in terms of mitigating environmental impact. Consumer's support in terms of reusing a bag till its last point in life cycle and recycling it rather than disposing to landfill, supported by government recycling policies, will reduce the environmental impacts made by different types of shopping bags.

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