The last decade of the twentieth century has seen the emergence of a strong interest in the environmental impact associated with the products that surround us and by which we obtain the many services that civilization relies on. This interest has been accompanied by the development of methods for environmental assessment of products (1-9). Environmental assessment of products includes all the processes needed for the product to run through its life cycle — from the extraction of raw materials through production of the materials which are used in the manufacture of the product to the use of the product and its disposal, with possible recycling of some of its constituents.
To perform Life Cycle Analysis (LCA) of any product, the whole life cycle starting from its birth to death or, in other words, from “cradle to grave” is to be taken into consideration. Raw material acquisition would include timber harvesting. The second stage is the material manufacturing stage. In this stage raw materials are processed into basic material of product manufacture. These materials move to the product manufacture stage where they are made into plastics. Product disposal by various ways and product recycling is the last stage in the life cycle.
The present study examines the detailed scenario of use of jute bags, and paper sacks as packaging, materials such as plastic (HDPE, LDPE) and non-plastic (tin, glass, jute and paper) packaging material for commodity products such as wheat flour (5kg), milk (1 lt), lube oil (5 lt) etc. using life cycle analysis as the principal methodology.
Product Life Cycle — Various stages
To start with, the whole life cycle of two packaging material viz PP-HDPE and jute has been completed. Life cycle of the above materials are divided into four phases: (I) Raw materials manufacture (II) Production of sacks (III) Usage (packaging and Transportation) (IV) Waste management (figure 2). Each phase has been evaluated taking into consideration energy and water requirement for the operation and emissions of harmful chemicals and gases during the same. Other effects as a result of these processes on the environment, such as depletion of natural resources, greenhouse effect etc is also evaluated.
Life cycle analysis is an effective tool to measure the impact of a product or process on the environment. The present study covers the environmental and resource impact of plastic pouches vis-à-vis glass bottles used for packaging milk; plastic film bags vis-à-vis jute bags used for packaging wheat flour; HDPE cans vis-à-vis tinplate cans used for packaging ‘lube oil’, from the stage of raw material extraction, production, use and disposal, taking into account all the inputs such as materials and energy consumption and the outputs like products, byproducts, waste materials and emissions at every stage.
The basis of this study has been considered as 100,000 litres of milk, 100,000 metric tonnes (MT) of wheat flour and one million MT of lube oil respectively in keeping with the view of the consumption in order of magnitude. This paper presents case studies of plastic bags against jute bags and glass containers.
Life Cycle Inventory
To start LCA, data has to be collected across all the different service groups and complied into one inventory called Life Cycle Inventory or LCI. A life cycle inventory consists of data collection and calculations to quantify the impact and outputs of a product life cycle. This inventory is the heart of the LCA method.
In a Life Cycle Inventory, the inputs and outputs of each life cycle stage are quantified. Process inputs can be divided into two kinds.
Environment Inputs — Inputs of raw materials and energy resources
Economic Inputs — Inputs of products, semifinished products or energy, which are outputs from other processes that must themselves be inventories.
Similarly there are two kinds of outputs:
Environmental Output — Outputs of emissions
Economic Output — Output of a product, a semifinished product or energy.
Data Collection and Treatment: When the system is defined, data for all the activities are collected. For each activity the data gathered comprise :
– Raw materials
– Products
– Energy use
– Emissions to air and water
– Solid waste
All data must be specified regarding to time and amount. They must be processed. Units must be commented to a standard set, preferably to SI units and data normalised, i.e., expressed in relation to a given output from each activity. The data required can be found in different places and data sources include:
– Producing companies
– Internal company and public statistics
– Waste management companies, wastewater treatment plant
– Legislation, e.g., regarding permitted air emissions from combustion plants.
– Branch organisations
– Other industrial experts or LCA experts
– Reports from LCAs carried out and similar projects
– Other literature, e.g., reports concerning average energy requirements for different forms of transport or on how consumers handle different types of products etc.
– Open databases intended for LCA are in the process of being established.
Allocation of Inputs and Outputs
In LCA, the term allocation means” distribution of environmental burdens”. When the life cycle includes processes that include several products, and the system being analysed is not expanded so that commend systems provide the same function, then allocation is necessary, i.e., there must be distribution of environmental burdens caused by a process with several products among different products. The following allocation methods have been used:
– The product being observed is accountable for all environmental burdens
– The environmental burdens are divided in proportion to the weights of the products
– The burdens are divided in proportion to the energy contents of the products
– The burdens are divided on a molar basis (in the case of chemical processes)
– The burdens are divided in proportion to the economic values of the products.
Not all allocation principles are relevant to all types of products.
Calculation
When the flow chart is complete, the system delimited and data collected, then the environmental burdens of the system can be calculated by following three steps.:
– The mass balance is solved i.e., the flow through each activity of the flow chart is calculated in relation to the flow represented by the functional unit.
– The contribution of each activity is calculated through multiplying the flow through the activity by its normalised data set.
– The environmental burdens of the whole system are calculated by summing up the calculations of all its activity.
The results of inventory analysis in an LCA are generally represented as a table or a chart of resources used and emissions and possibly also include the solid waste associated with a functional unit of the product. The results of momentary analysis in an LCA may be evaluated as such or further in an input assessment.
Data Quality
Different types of data may be used in LCA inventory analysis. Data based on best technology currently available is appropriate to use for LCA for product development. It is important to have input data as up to date as possible for more efficient processing.
Recycle Loops
Recycle loops in the lifecycle of a product add another layer of complexity to completing a life cycle inventory. Products can be recycled in a number of different ways. If glass bottles are cleaned and refilled it is called recycled product. Thus, product recycling is reuse of an item after its original use.
Producted remanufacture occurs when an item is put to different use after its original purpose has been fulfilled, such as when newspapers are shredded and used for packaging.
In material recycle, the materials in an item are used as feedstock in material production. An example of material recycle is the production of steel ingots from junked cars.
Aggregation Categories
Other than the resource consumption, most evaluation schemes aggregate into at least four categories or environmental compartments, viz. energy consumption, air emissions, water emissions and solid waste.
Energy consumption: Energy consumption can be conveniently aggregated using the common currency of physical units, i.e. megajoules (MJ). Using the megajoules of thermal energy allows inclusion of electrical energy by use of the appropriate conversion efficiency. Combining all forms of energy, however, may obscure significant information, since energy may be consumed as inherent energy of raw materials, or in processing or transport. To determine where energy savings might be made, it is useful to distinguish between these categories, as occurs in at least one model.
Most models do not generally consider energy released during the life cycle, but this can have major environmental effects. Energy emissions to air may have negligible effects, but heat energy released to water may alter ecosystems significantly.
Emissions: Major problems arise in attempting to aggregate emissions for this same reason, i.e. the different nature of the materials released. Again, the simplest method of aggregation is to sum the masses of materials released, but this is not appropriate or useful, since a gram of sodium chloride emitted is not equivalent to emission of one gram of potassium cyanide! Emissions need to be weighted before aggregation to take into account their different properties.
Results and Discussion
Case Study I: Plastic Pouch vis-à-vis Glass Bottle for Milk Packaging:
The study discloses that for producing plastic pouches for packaging of 100,000 litres of milk, the plastic raw material required is only 0.40 MT (Table 1) but for packaging of same quantity of milk with glass bottles, the raw material required is 45.4 MT of glass. The results of this analysis are organized in two categories: resource utilization and atmospheric emission.
The emission of CO2 for the materials has approximately the same profile. However, the analysis of input effects indicates remarkably high emission of CH4 emission in case of production of glass. The comparative study on emission during transportation also shows significantly excess generation of CO, CO2 and NOx as compared to that in case of plastic pouches [Table 2(a) and 2(b)].
Case Study II:
Plastic Bag vis-à-vis Jute Bag for Wheat Flour Packaging:
The study discloses that for producing packaging with plastic film bags for one 100,000 MT of wheat flour, the raw material required for packaging is only 680 MT (Table 5). But for the same quantity of packaging with jute bags require 1960 MT of packaging material. The results of this analysis are organised in two categories: resource utilisation, water and atmospheric emission.
Phase I of jute involves absorption of CO2 from the atmosphere [Table 6(c)] but Phase II involves emission of CO2 as shown in Table 6(b). This benefit of Phase I is lost during the transportation phase, where, because of excess weight, it leads to consumption of excess fuel resulting in severe atmospheric pollution. The emissions of CO2 for plastic film bags are higher in phase I but lead to overall less CO2 emission because of its light weight during the transportation phase. The analysis of input effects indicates remarkably high emission of CH4 emission in case of production of jute. The comparative study on emission during transportation also shows significantly excess generation of CO, CO2 and NOx in case of jute bags as compared to that in the case of plastic film bags.
Case Study III :
HDPE Cans vis-à-vis Tinplate Cans for Lube Oil Packaging:
The study discloses that for producing packaging with HDPE cans for one million MT of Lube Oil, the raw material required for packaging is only 63,218 MT (Table 3). But for the same quantity of packaging with tinplate cans, we require 86,207 MT of packaging material. The results of this analysis are organised in two categories: resource utilisation, water and atmospheric emission.
During the transportation phase, excess weight of the tinplate cans leads to consumption of excess fuel resulting in severe atmospheric pollution. The emission of CO2 for HDPE cans is higher in Phase I [Table 4(a)] but leads to overall less CO2 emission because of its light weight during the transportation phase. The analysis of input effects indicates remarkably high emission of CH4 emission in case of production of Tin. The comparative study on emission during transportation also shows significantly excess generation of CO, CO2 and NOx in case of tinplate cans as compared to that in case of HDPE cans.
Conclusions
Though plastics are relative newcomers, their use in packaging of milk/wheat flour/lube oil commodities adheres to the basic tenets of sustainable development more than alternative materials like glass, jute and tinplate, if one considers the consumption of energy and emission of gases. An analysis of the comparable life cycle with conventional materials clearly tells us that plastics are economically affordable, socially acceptable and environmentally effective.
From this study we can claim that the overall loss to environment from plastic pouches is less than that from alternative materials. The difference seems significant. The choice of product end-of-life (work) management strengthens this assessment.
The need of the hour is educating the public of what to do with such waste packaging materials and how to dispose of them for recycling — to lessen the stress on waste management and to do proper justice to resource management.
References
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– Boustead, I. A practical Guide to choosing the methodologies Proceedings of IIR Conference: The Practical Application of Product Life Cycle Analysis. IIR, London, UK (1991).– ENDS (1990). Life-cycle Analysis: an environmental management tool for the 1990s. Environmental Data Services Report 188: 19-21 (1990).
– Hunt, R.G., Sellers, J.D. and Franklin, W.E. Environmental Impact Assessment Review, (eds L. Susskind and T. Hill) Elsevier (1992).
– SETAC A Technical Framework for Life-cycle Assessments. Society for Environmental Toxicology And Chemistry, Washington. DC, USA (1991).
– ISO 14042 (1999) Environmental Management- Life Cycle Assessment- Life Cycle Impact Assessment. ISO/FDIS (1999).
– ISO 14043 (1999) Environmental Management- Life Cycle Assessment- Life Cycle Interpretation. ISO/FDIS(1999)
– Boustead, G.F. Hancock Energy and packaging. Ellis Horwood publishers (1981).
– Ghosh, A.K., Life cycle Analysis of PP-HDPE Woven Sacks vis-à-vis Jute/Paper sacks in terms of environmental studies, Indian Centre for Plastics in Environment, Thompson press, New Delhi (2002).
