تجزیه و تحلیل اقتصادی بازیافت کاغذ چوب رو در رو به عنوان ماده خام

Concerns for the environment has forced many firms define policies that protect the environment within which they operate. This paper presents a linear optimization model for paper industry to compare total system cost of wood as a raw material with recycling of waste paper. Objective of the proposed model is to minimize the cost of paper in the supply chain. Costs included in the objective functions are: costs for collection of raw material, transportation, inventory, manufacturing, segregation and disposal (during recycling). The model also includes the economic implications of using these alternative material sources on environment as well as quality of final product. To gain further insights into system behavior, sensitivity analysis, shortage analysis and indifference curve analysis have been performed. The analysis clearly reveals that the paper recycling is an economical option compared to wood as a raw material. The paper analysis highlights various strategies that could be followed under different market conditions.

Environmental issues are becoming increasingly important for the product designers and manufacturers. The traditional assumption that the cost of ecological burdens is to be shared by the society as a whole is no longer acceptable. In several countries, waste management policies are characterized by the hierarchy of options in which waste minimization, reuse and material recycling are all considered preferable to energy recovery. This concern for the environment has motivated increased interest in the reverse material flows, which has become the subject of growing attention over the last decade (Fleschmann et al., 1997). The reverse flow is a part of a closed loop supply chain, which consists of forward supply chain and reverse supply chain. According to the Council of Reverse Logistics Management, reverse logistics is defined as the process of planning and controlling the efficient, cost effective flow of raw material, in-process inventory, finished goods and related information from the point of consumption to the point of origin for the purpose of recapturing value or proper disposal (Krumwiede and Sheu, 2002). The initiatives that generate a reverse flow are basically of three types (Murphy, 1986): from customer who returns goods, from industry interested in recycling and from the government which aims to promote practices of this type. Recent reviews and literature compilation either on models to support reverse logistics or on the business prospective could be found in Fleischmann et al. (1997) and Guide et al. (2000). Waste accumulates over time unless decomposed in the ecosystem or recycled. Waste is a strategic issue for a variety of reasons. Companies are seeking to reduce cost by minimizing all types of waste in the supply chain. There has been a considerable increase in the degree of national and international regulation and legislations governing waste management. Finally, the customers are becoming more concerned about the impact of product and services on the environment. Correspondingly, organizational paradigms have been created as ecological and environmental issues play a more important role in corporate strategies (Sarkis, 1995). Piler et al. (2004) suggests that the management of reverse logistics may suppose a significant difference with respect to the competitive edge of the firm within the industry and become a beneficial as well as sustainable business strategy for the company. This new concern has led companies to develop strategies that integrate environmental management (Brysson and Donohue, 1996; Handfield et al., 1997); in many cases actually constituting a competitive edge for the organization (Sarkis, 1995; Autry et al., 2001). Due to these reasons, waste management has received increasing attention in the last decades and the emphasis has been shifting towards recycling as one of the alternative ways of managing waste. Several researchers have used functional methods to model waste and waste management process. Sarkis (1995) modeled the product development lifecycle and its impact on the environment using the integrated CAM functional modeling method, known as IDEF0 (Bravoco and Yadev, 1985). A functional model of the supply chain for waste management, product recovery and reuse that gave an idea about the forward and return flows of material was investigated by Thierry et al. (1995). Far reaching policy measures have also been undertaken in many economically advanced countries, to promote recycling of municipal waste. Huhtala (1997) use dynamic models to analyze waste management in general. He has developed a model for determining optimal levels of material recycling and land filling, in which recycling benefits from a contingent valuation study are included. Incineration is however not included. Eichner and Pethig (2001) use a static general equilibrium model to study efficiency restoring policies. In their model, material is first extracted, then used for producing a consumption good, recycled and finally treated to reduce environmental damage. The composition of waste collected by the waste pickers in Mumbai, India (Beukering et al., 1996) and the composition of municipal waste in an advanced economy, the USA (EPA, 2000) reveal that the proportion of plastic and paper in waste generated are very significant and need immediate attention in order to save the environment from getting polluted. Recycling provides a better option to reduce paper and plastics wastes. Studies specially addressing the problems related to the issues of recycling of wastes/hazardous wastes such as effluents, glass, plastics, paper, etc. are fewer (Koo et al., 1991; Stepnowski et al., 2002; Bartels, 1998; Van Notten, 2000; Gupta and Chakraborty, 1984; Chang and Wei, 2000). The driving forces behind the above-mentioned studies were primarily cost saving or concern for environment (through regulations or motives). Recycling is thus one of the most important techniques through which the rate of degradation of the environment can be slowed down. However, there exists limited literature on the economic analyses for recycling of paper to assist the management in decisions-making, formulating policies and strategies. Recent publications about wastepaper concentrate on the high volatility of wastepaper prices (Ackerman and Gallagher, 2002), examine inter-country differences in wastepaper recovery and utilization (Bystrom and Lonnstedt, 1995; Berglund et al., 2002) or discuss whether wastepaper should be recycled or incinerated (Hanley and Slark, 1994; Leach et al., 1997; Hekkert et al., 1999; Samakovlis, 2003; Klieineidam et al., 2000). Grace et al. (1978) and Yohne (1979) carried out economic studies of the supply and demand or trade, with wastepaper. They examined international trade and its importance to price. Price expectations and the effect of price changes have been analyzed by Edwards (1979), Deadman and Turner (1981), and Kinkley and Lahiri (1984). Anne and Timo (1998) and Huttunen and Pirttila (1998) analyzed the structure of the recovered paper market. Both the researchers use statistical approach supported with a qualitative market analysis to get a view of the short-term price trend. Some literatures could also be found on the effect of environment and environmental regulations on the paper industry. Gray and Shadbegian (1998) estimated the impact of environmental regulation on investment decision for the US pulp and paper industry between 1972 and 1990. They analyze two aspects of the investment decisions: the specific production technology installed in a new mill, and annual investment spending at existing mills. Baumgartner and Winkler (2003) discussed in details the case of price ambivalence in wastepaper. They analyzed how environmental policy, regulatory institutions, market forces and technology have interacted over time to generate this phenomenon and identified the underlying causes. Sharma et al. (1997) conducted a comprehensive case study of Mumbai (India) to investigate the economic, social and environmental impact of international trade of wastepaper for recycling purposes between industrialized and developing countries. Results of static material balance flow model indicate that environmental impacts are less with increased trade and economically the paper sector in India benefits from free trade. Bloemhof-Ruwaard et al. (1996) developed an environmental life cycle optimization model for the European pulp and paper sector. This was done through a network flow model (using linear programming (LP) technique) to derive environmental policies that are defendable and predictable, and can explore the potential for reducing the environmental impact on the sector. Despite the current relevance that recycling of paper seems to have, literature considering the combined economic effect of environmental, quality produced and other related supply chain costs on paper industry with different basic raw material is yet to be studied. The manufacturer still prefers to produce paper mainly from virgin wood pulp vis-à-vis wastepaper as raw material in a country like India (which faces shortage of virgin wood pulp). The purpose of this paper is to convince the manufacturer about the economic advantage of recycling as compared to virgin wood pulp and suggest strategies to encourage the manufacturer to prefer recycling option. A LP optimization model is developed to compare the supply chain cost for the recycling of paper vis-à-vis wood as raw material in Indian context. Shortage analysis of input raw material at each echelon of supply chains (wood as well as wastepaper) are studied to help manufacturers, know the maximum limit of raw material shortage which makes recycling an economical option for manufacturing paper. To analyze the degree of influence of raw material and its collection costs on the reverse supply chain, sensitivity analysis has been performed on the collection cost and raw material cost of wastepaper. Further, trend analysis of wastepaper recovery has also been conducted to know the minimum degree of paper recovery required to make recycling a viable option. Finally, indifference curve analysis with raw material cost and its collection cost is performed on the models to provide the manufacturer an insight of various strategies to be followed in different shortage (wood vs. wastepaper) scenarios.

Reverse logistics is an area of growing importance. In this paper a linear cost optimization model has been formulated for the two prominent alternatives of raw material in the paper supply chain viz. wood and wastepaper. Along with the commonly accounted logistics costs, i.e. costs of collection, transportation, inventory, manufacturing, segregation and disposal, the inclusions of quality and environmental costs added a new dimension to the objective function of the models. The model has taken care of the globally relevant topic of manufacturing eco-friendly products. The present study helps in selecting the most economical raw material for manufacturing paper by considering all the above mentioned supply chain related as well as environmental costs. Further, shortage analysis, sensitivity analysis, trend analysis and indifference curve analysis were performed on the model for developing various strategies under varying degree of wood and wastepaper shortage scenarios. As the prospect of shortage of raw material looms large over the industry, each of these analyses can simulate the effect of shortage of basic raw materials (wood pulp and wastepaper) on the supply chain costs. The shortage analysis confirms that for degree of supply chain shortage (below 80%) recycling is an economical option of manufacturing paper. The result will encourage the manufacturer/managers and supply chain partners to consider wastepaper as raw material for an alternative and economic option of manufacturing paper compared to virgin fiber (wood pulp) as raw material. Sensitivity analysis and indifference curve analysis guide the supply chain managers to devise techniques and formulate strategies for increasing the rate of wastepaper recovery. One alternative of increasing recovery rate is offering economic incentives to vendor–customer and investing in appropriate collection system. Using these analyses the maximum percentage increase in raw material collection cost and raw material cost can be ascertained. Paper industry also benefits from this strategy as it will lead to decrease in total segregation, transportation and inventory cost of non-relevant wastepaper in the recycled paper supply chain. Finally, trend analysis of wastepaper recovery guides the recycled paper supply chain manager to choose strategies for colleting at least the minimum required quantity of wastepaper to make recycling option economic vis-à-vis wood as raw material. It can thus be concluded that by offering certain incentives to vendor–customer and investing on the efficient collection system, recycling is a better option as compared to wood as raw material. This also improves the environment due to reduction in pressure on the limited natural resources (i.e. forest cover) as well as solid waste since the wastepaper in the surrounding is utilized in a desirable and profitable manner. It envisaged that the quantitative analysis presented in this paper can play a vital role in the decision process of a paper manufacturer. The choice for the supply chain strategy could be justified based on the quantitative reasons. However, limitations of the present study pertain to ignoring the effect of internal distributions on system wide supply chain cost and assumption of “no loss condition” of any variety. Difficulty in obtaining the estimates of the environmental cost is also a major limitation of the study. The linear model presented can possibly be extended to include non-linearities, stochasticity of parameters and multiplicity of objectives in future studies on this topic.