A Cradle to Grave Approach: An Effective Solution for Reduction in Environmental Pollution

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1 A Cradle to Grave Approach: An Effective Solution for Reduction in Environmental Pollution SAMPATRAO D. MANJARE Chemical Engineering Group, Birla Institute of Technology & Sciences (BITS), Pilani, Goa Campus, Zuari Nagar, Goa. Fax: ANEES Y. KHAN Chemical Engineering Group, Birla Institute of Technology & Science (BITS) Pilani, Rajasthan, India. ABSTRACT Due to the environmental aareness among the people, industries have started to shift their attention from pollution remediation to pollution prevention. Industries and businesses have started to assess ho their activities affect the environment. Society has become concerned about the issues of natural resource depletion and environmental degradation. Many businesses have responded to this aareness by providing greener products and using greener processes. The environmental performance of products and processes has become a key issue, hich is hy some companies are investigating ays to minimize their effects on the environment. Many companies have found it advantageous to explore ays of moving beyond compliance using pollution prevention strategies and environmental management systems to improve their environmental performance. One such tool is called life cycle assessment (LCA). This concept considers the entire life cycle of a product. The complex interaction beteen a product and the environment is dealt ith in the LCA method. LCA systematically describes and assesses all flos to and from nature, from a cradle to grave perspective. This article provides an introductory overvie of LCA. The uses of and major components of LCA and ho LCA is the most effective environmental performance tool for industries and business activities are discussed. INTRODUCTION Environmental issues have gained greater public and legal scrutiny in the past 25 years. The public has become more aare and interested in the consumption of goods and services and their impact on the natural resources and the quality of the environment. In the past 12 years, an increasing number of firms have been shifting their focus from remediation of pollutants to pollution prevention. This has included green design activities and replacing some materials and manufacturing processes ith more ecofriendly ones. These efforts on behalf of the companies have drastically reduced the levels of industrial pollution. Industry is realizing that the impact of a product on the environment starts ith the design and ends at the ultimate disposal of the product after its use. What considerations are made during the design phase of a product affects the hole life cycle. It is important to determine the environmental impacts of the manufacturing process, the product and its ability to be recycled. While reducing the impact a company and its product make on the environment is a good idea, the cost associated ith minimizing these impacts must be considered. Environmental compliance has been considered a cost of doing business and staying out of jail. The increased use of aste minimization programmes has not only reduced the cost of compliance (hich goes up over time), but has loered the cost of producing products. In a number of cases, the quality of product has improved. This, in itself, reduces costs and improves competitiveness of the products. In the global marketplace, the reduced impact of products on the environment has serious marketing impact. Sound environmental practices ill result in designs that meet or exceed the requirement of the countries here they ill be sold. It is reasonable therefore to consider the total impact on the environment of a product and plan means of reducing that impact during the planning and design phase of the product life cycle(1). This is possible by utilizing Life Cycle Assessment (LCA) methodology, hich has been referred as the green technology in this paper. This paper discusses about the conceptual background of LCA, its frameork and also the implementation of the various phase of the methodology. Chemical Weekly October 24,

2 Life Cycle Assessment LCA is a quantitative environmental performance tool, essentially based around mass and energy balances but applied to a complete economic system rather than a single process. In terms of system boundary definition, this represents an extension to the conventional system analysis, in hich the system boundary is dran around the process of interest only. Materials 2 Extraction and Processing 1 Transportation Production Transportation Use Figure 1 illustrates the ay in hich LCA can complement conventional process analysis. While chemical or process engineering is normally concerned ith the operations ithin the system 1, LCA considers the hole material and energy supply chains, so that the system of concern becomes everything ithin system boundary 2. The material and energy flos that enter, exist in or leave the system include material and energy resources and emissions to air, ater and land. These are often referred to as environmental burdens and they arise from activities encompassing extraction and refining of ra materials, transportation, production, use and aste disposal of a product or process. The potential effects of the burdens on the environment, i.e., environmental impacts, normally include global arming potential (GWP), acidification, ozone depletion (OD), eutrophication etc. The LCA methodology is still under development. At present, the methodology frameork comprises four phases: (2) Goal and Scope Definition: Selecting the system boundaries (Fig. 1) to ensure that no relevant parts of the system are omitted. Inventory Analysis: Performing Disposal Transportation Re-use or recycling Transportation Disposal Waste mass and energy balances to quantify all material and energy inputs, astes and emissions from the system, i.e., the environmental burdens. Impact Assessment: Aggregating the environmental burdens quantified in the inventory analysis into a limited set of recognized environmental impact categories, such as global arming, acidification, ozone depletion, etc. Interpretation: Using the results to reduce the environmental impacts associated ith the product or process. Goal and Scope Definition The most common LCA goal is to conduct an assessment of the environmental attributes of a specific product or process and to derive information from that assessment on ho to improve the environmental performance. If this exercise is conducted early in the design phase, the goal may be to compare to or three alternative designs. If the design is formalized, the product is in the manufacture, or the process is in operation, the goal can probably be no more than to achieve modest changes in environmental attributes at minimal cost and minimal disruption of an existing operation(1). Scope definition refers to hat is included and excluded from each step in the process. The scope plays the major role in the effort, time, and expense that ill be involved in the LCA. If confined to the subset of life stages or a limited selection of impacts, the LCA ill be much more efficiently carried out. Figure 1: Stages in the lie cycle of a product (system boundary: 1, process analysis: 2) The results may be a report of limited usefulness, hoever, if potentially important factors have been omitted. 186 Chemical Weekly October 24, 2006

3 Resource conservation Nonetheless, experienced assessors often opt for restricting the LCA scope in order to increase the tractability. Their concept is that significant benefits can often come from a limited LCA(1). It is, in fact, not assured that more substantial benefits ill emerge from more extensive LCA, and an LCA so broadly scoped that its successful completion is uncertain may turn out to yield no benefits at all. The outcome of the LCA study can have a positive impact on human health, the ecosystem, and natural resources, as shon in the Figure 2. It should be apparent that the choice of LCA boundaries can have enormous influence on the time scale, cost, and tractability of the LCA. The best guidance that can be given is that the boundaries should be consistent ith the goals of the exercise. The goals of the LCA thus define much of the LCA scope, as ell as the depth of the inventory and impact analysis activities. Functional unit can become crucial hen actually implemented in LCA, Pollution Prevention Life Cycle Assessment Sustainable Ecosystem Figure 2: Life cycle goals hich is defined as amount of product, material, or service to hich the LCA is applied. This definition becomes especially important hen to rather dissimilar items are being compared. The choice of the functional unit is not straightforard, and it requires the knoledge of ay in hich the product, material, or service ill be used, the actual function that is being satisfied, and perhaps even the anticipated longevity of the item being assessed. A good choice can support a useful LCA outcome; a poor choice may render the LCA essentially meaningless. Inventory Analysis Economic System It refers to performing mass and energy balances to quantify all material and energy inputs, astes and emissions from the system i.e., the environmental burdens. It should be noted that inventory in LCA refers to the ra materials inputs and emission outputs, rather than to a quantity of stored materials. After the scale of the LCA has been established by defining the scope, necessary data is collected. The process is begun by constructing, in cooperation ith the design and manufacturing team, an inventory flo diagram. The aim is to list, at least qualitatively, but preferably quantitatively, all inputs and outputs of the materials and energy throughout most or all life stages. The cataloging of inputs and outputs must have an objective. The specific objectives for conducting the inventory include, but are not limited to, the folloing (3): Compare input and output associated ith alternative products, materials, or processes. Determine points ithin the life cycle or given process here the greatest reduction in resource requirements and fugitive emissions might be achieved. Establish a comprehensive baseline. Assist in training personnel responsible for reducing the environmental impacts associated ith product or processes. Assist in the substantiation of product claims about reducing their impact on the environment. Supply information for the evaluation of public policy affecting resource uses, recycling, or releases. The obtaining of ra materials and the manufacturing stages can be and usually are complex. Because of this e can establish sub-boundary conditions for these activities. An example is shon in Figure 3. In this figure the manufacturing boundary has included three fundamental steps i.e., material manufacture, product processing and packaging and distribution. Figure 4 shos more specifically about preparation of inventory for sulphur dioxide gas treatment ith limestone. Block diagram representations Chemical Weekly October 24,

4 Ra Materials Limestone Process ater Cooling ater Electricity Material Manufacture Product Processing Packaging & Distribution Figure 3: Manufacturing stage SO 2 Limestone scrubbing ith forced oxidation and filtration (Including et gas cleaning) Saleable gypsum Products & Wastes SO 2 CO 2 Sludge Wasteater Figure 4: Ra materials, utilities, products and aste per ton of SO 2 treated for limestone scrubbing options Replicable: The sources of information and methodology are sufficiently described or referenced so the same results could be obtained by a skilled person and evidence ould be available to explain any deviation. Scientific: Scientific based analysis is used to obtain and process the data. Comprehensive: All significant materials and energy uses and aste releases are included. Any element missing because of data unavailability or cost and time are clearly documented. Details: The inventory is conducted in a manner and to a level of detail commensurate ith the purpose of study. Peer revieed: If the study results are to be used in public manner, they should be peer revieed using accepted protocol. Useful: The users of the study can make appropriate decisions in areas covered by inventory. Any limitation regarding the utility of the study should be clearly noted. are helpful for making material and energy balances more clear and tangible. Input and output material streams are shon ith the help of arros. These block diagrams can be used for breaking the system into subsystems. The use of this type of modeling facilitates both simple and complex processes and systems(3). The model makes use of data gathering and checksheets for easier understanding and minimizes the missed data. A sample checksheet is shon in Table 1. Because the user may ant to determine here the opportunities are in the product stream to minimize environmental impacts, this method can 188 provide a less costly means of analysis and data gathering than conventional methods. Spreadsheets are also useful for data integration as shon in Table 2, giving idea about the complete process. It is recognized that inventories ill vary from screening to extremely technical and practical as possible. To be useful tool, hoever, a life cycle inventory should meet, as a minimum, the folloing criteria(1): Quantitative: All data should be quantified and documented ith suitable quality control. Any assumptions in the data and methodology must be specified. The meeting of these criteria should make the life cycle inventory report useful, technically supportable, unbiased, and applicable. Impact Assessment Quantitative information on materials and energy flos is acquired in the inventory stage of the LCA. No the environmental influences on the activities revealed by the LCA inventory analysis on the specific environmental properties must be accurately assessed, and the relative changes in the affected environmental properties must be given some sort of priority ranking. Together, these steps constitute LCA s impact assessment. Chemical Weekly October 24, 2006

5 Table 1 Sample checksheet Data Checksheet Project Name: Investigator: Date: Reference no. : Project ID no.: Company: Input items Quantity Units Ra materials kgs/litres KW/ Hp/ MJ Other Output items Quantity Units Materials kgs/litres KW/ Hp/ MJ Other Assessing environmental influences is complicated procedure, but it can be, in principle at least, be performed by employing stressors, hich are items identified in the inventory analysis that have the potential to produce changes in the environmental properties. Conceptually, hoever, the needed stressor relationships can be imagined to established and available for use. By combining LCA inventory results ith stressor relationships, a manufacturing process might be found, for example, to have a minimal impact on local ater quality, a modest impact on regional smog, and a substantial impact on stratospheric ozone depletion. For example, lead in motor vehicle exhaust is a stressor because lead is the systematic poison for animals and humans. The relationship among stressors and the environment are developed by the environmental science community, and are not alays available ith the degree of detail and precision required. Thus, the first stage of LCA impact assessment is the identification of stressors and environmental concerns to hich they are related. The result of this stage is an estimation of burdens, that is, of potential impacts. Table 3 shos the environmental impact categories. The impact assessment can be structured according to the folloing steps: Classification It begins ith the ra data from the inventory analysis on flos of materials and energy. Given that data, the classification steps consists of identifying environmental concerns suggested by the inventory analysis flos. Some of the pollutants emitted during product manufacturing, use or reuse are given here. These pollutants are classified as: carbon dioxide (CO 2 ), nitrogen oxide (N 2 O), methane (CH 4 ), volatile organic compounds (VOCs), chlorofluorocarbons (CFCs), chlorinated hydrocarbons (HC), sulphur dioxide (SO 2 ), nitrogen oxides (NO x ), hydrochloric acid, ammonia (NH 3 ), hydrogen fluoride (HF), phosphate ion (PO 4 3- ), phosphorous (P), alcohols, ketones, ethers, olefins, acetylenes, aromatic and aldehydes. Characterization It is process of combining different stressor-impact relationships into a Table 2 Sample spreadsheet for data integration Purpose: What is being studied? Why? Scope/ Limitation: What are the boundaries? Assumptions? Inputs Outputs Other Process no. Air Water Materials Air Water Materials Ra materials Packaging Products Wastes Chemical Weekly October 24,

6 Table 3 Environmental life cycle assessment categories for impacts(4) Enhancement of the greenhouse effect Depletion of ozone layer Acidification Potential Nitrification Human toxicity Ecotoxicity Photochemical Oxidant Formation Depletion of abiotic resources Depletion of biotic resources Waste heat Noise Damage of ecosystem & landscapes Corrosion Visibility Odour Victims common frameork. For example, on a time scale of 100 years the contribution of 1-kg methane to global arming is 42 times as high as the emission of 1-kg CO 2. This means that if the characterization factor of CO 2 is1; the characterization factor of CH 4 is 42. Thus, the impact category indicator result for global arming can be calculated by multiplying the life cycle inventory result ith the characterization factor. The above-mentioned pollutants are characterized in Table 5. Localization It is the operation of comparing environmental impacts occurring in different regions ith different characteristics. For example, the process of localization attempts to compare the emission of 1-kg of moderately toxic material into a pristine ecosystem ith the impact of the same emission into a highly polluted ecosystem. Valuation 190 Environmental Index = It is process of assigning eighting factors to the different impact categories based on their perceived relative importance as set by social consensus. For example, as assessor or some international organization might choose to regard ozone depletion impacts as tice as importance as loss of visibility, and apply eighting factors to the normalzed impacts accordingly. The most contentious aspect of LCA methodology is the evaluation phase arising from the selection of the relative eightings for various environmental effects. One approach to a single index in the evaluation phase has been described by Annema (6). In this method, the score for each category from the classification step is divided by the national score for that category. The resulting fractions are then added for all classification categories. Thus, The national scores for each classification category are calculated using pertinent national emission consumption data. The approach involves some inherent eighting classification categories derived from the contribu- magnitude of category i for product under study magnitude of category i from all man made sources ithin specified region tion of the product under study to national effects for each category. An important consideration that plays a role in the prioritization of impacts is that a single impact generally has many stressors, and a single stressor has many impacts. As a consequence, the industry-environment interaction generally embodies a summation of impacts of different magnitudes and different spatial and temporal scales. The result is that a choice beteen to design options may involve tradeoffs such as choosing beteen having a modest influence on a single impact of high importance or smaller influences on several impacts of loer importance. One approach of linking stressors and impacts is a series of matrix displays, the axes of matrices being Technological Activities (specific activities or industries that generate stressors such that gases or particles) and Critical Properties (specific impacts). A matrix of this type for atmospheric concerns is shon in Table 6. To construct this figure, a critical atmospheric concern such as precipitation acidification and its direct and indirect chemical causes are linked ith sources responsible for initiating those interactions. The result is a matrix that shos the impact of each potential source of atmospheric change on each critical atmospheric component. A rough qualitative assessment of significance is included. The diagram also includes estimates of reliability, an important component of an assessment effort. The matrix is constructed ith separate ros for industrial operations and for the major energy generating processes, and can obviously expanded Chemical Weekly October 24, 2006

7 Table 4 Classification of the pollutants (5) Impact Categories Pollutants Global arming Carbon dioxide (CO 2 ), nitrogen oxide (N 2 O), methane (CH 4 ), volatile organic compounds (VOCs) Ozone depletion CFCs, chlorinated HCs Acidification potential Sulphur dioxide (SO 2 ), nitrogen oxides (NO x ), hydrochloric acid, ammonia (NH 3 ), hydrogen fluoride (HF) 3- Eutrophication NO x, NH 4+, N, phosphate ion (PO 4 ), phosphorous (P). Photochemical oxidant potential VOCs including alkanes, halogented HCs, alcohols, ketones, ethers, olefins, acetylenes, aromatic and aldehydes Interpretation This step essentially combines the finding from the inventory analysis and impact assessment to develop conclusions and recommendations. It uses the goals and scope of LCA, as the basis for the development of conclusions and recommendations. It results in a report containing methodologies, data sources, calculations, and findings of LCA in a format consistent ith the goals for the study. CONCLUSIONS in much greater details than is shon here. The simplest impact assessments of Table 6 involve only a single cell of the matrix. A typical example is the study of the impacts of a single source, such as a ne coal-fired poer station, on a single critical atmospheric component, such as acidification potential. For the purpose of policy and management, it is desirable to assess the impacts of a single source on several critical environmental properties. The coal combustion study noted above ould fall into this category if the impacts ere assessed not only on acidification, but also on photochemical oxidant production, material corrosion, visibility degradation, heavy metal emissions, etc. If desired, the columns could be summed in some ay (such as assigning numbers to potential importance ratings) to give the net impact of the ensemble of sources on each critical property. Similarly, the ros could be summed in some ay to give the net effect of each source on the ensemble of properties. LCA is a quantitative environmental performance tool, essentially based around mass and energy balances, but applied to a complete economic system rather than a single process. LCA has to main objectives. The first is to quantify and evaluate the environmental performance of the process or product from cradle to grave. Another objective is to provide a basis for assessing improvements in the environmental performance of the system. LCA includes green design activities and replacing some Table 5 Characterization of pollutants (5) Classification Pollutants Characterization Global arming Carbon dioxide (CO 2 ), Nitrogen oxide (N 2 O), Global arming is expressed relative to CO 2. Methane (CH 4 ), Volatile organic compounds (VOCs) Ozone depletion CFCs, chlorinated HCs. Ozone depletion is expressed relative to CFC-11. Acidification potential Sulphur dioxide (SO 2 ), nitrogen oxides (NO x ), Acidification potential is expressed relative hydrochloric acid, ammonia (NH 3 ), hydrogen to SO 2 fluoride (HF) Eutrophication 3- NO x, NH 4+, N, phosphate ion (PO 4 ), Eutrophication potential is expressed relative phosphorous (P) to phosphate ion Photochemical oxidant potential VOCs including alkanes, halogented HCs, Photochemical oxidant potential is expressed alcohols, ketones, ethers, olefins, acetylenes, relative to ethylene aromatic and aldehydes Chemical Weekly October 24,

8 Table 6: An initial ensemble assessment of impacts on the global atmosphere (3) materials and manufacturing processes ith more environmentally friendly ones. REFERENCES 1. Caimborne D., Environmental Life Cycle Analysis, Leis Publishers, Ne York 2. ISO (1997), Environmental Management-Life Cycle Assessment 192 Part 1: Principles and Frameork. ISO 3. Graedel T., Streamlined Life Cycle Assessment, Prentice Hall NJ 4. Heijungs, R. (final editor), 1992, Environmental life cycle assessment of Products, Guide-October 1992 (Centre of Environmental Science, Leiden, The Netherlands). 5. Azapagic A., R. Clift, The Applications of life cycle assessment to process optimization, Computers and Chemical Engineering, 23 (1999), ISO (1997), Environmental Management-Life Cycle Assessment Part 1: Principles and Frameork. ISO Chemical Weekly October 24, 2006