Product Recovery System Research Articles

Decision and information interoperability for improving performance of product recovery systems

Enterprises around the world are employing product/resource recovery practices to overcome global competition, meet heightened environmental regulations, and seek additional profit making opportunities. These factors in addition to the inherent cost and complexity of recovery processes are due to multidimensional factors and relationships associated with the quality, variety, timeliness, demand changes, and logical processing of product returns. A Reverse Enterprise System (RES) perspective will give scope to develop a flexible system that can handle products with various options and greater return volumes and variability. It explores the various recovery functions and product lifecycle stages and suggests some key business and performance measurement strategies that can be employed to be successful in returns handling. We observed that different recovery nodes act in a relatively autonomous fashion to decide what type and level of flexibility to use, what and when the information is required to be shared for improving decision performance and obtaining benefits from the recovery process. Finally, this paper proposes a semi/partially and fully flexible decision model that facilitates decision and information interoperability functions from the perspective of an enterprise engaged in or planning to be engaged in product recovery processes.

Integrating reverse logistics into the strategic planning of a supply chain

This paper proposes a mixed-integer programming (MIP) model for the strategic production and distribution planning of a supply chain (SC) integrating reverse logistics system. Such reverse logistics planning addresses the collection, recovery and marketing of recovered products, in addition to returned components and packing/wrapping materials. The model includes an approach that uses retail outlets as a two-way channel for marketing new products, collecting used/returned products and remarketing recovered products as a way of promoting an effective product recovery system in SC operation and optimising costs. The recovery of products/components is planned through a pool of recovery service providers (RSPs), so that maximum recovery can be ensured through combining the expertise of RSPs within optimum costs. The model follows a two-step process that addresses strategic decisions about product recovery in the first step, and the integration of the recovery process into overall SC decisions in the final step. A numerical example illustrates the applicability of the model. A sensitivity analysis has been conducted to show the effects that changes in the recovered product quantity have on the overall SC performance.

Lot sizing for a single product recovery system with variable setup numbers

Inventory systems for joint remanufacturing and manufacturing have recently received considerable attention. In such systems, used products are collected from customers and are kept at the recoverable inventory warehouse for future remanufacturing. In this paper a production–remanufacturing inventory system is considered, where the demand can be satisfied by production and remanufacturing. The cost structure consists of the EOQ-type setup costs, holding costs and shortage costs. The model with no shortage case in serviceable inventory is first studied. The serviceable inventory shortage case is discussed next. Both models are considered for the case of variable setup numbers of equal sized batches for production and remanufacturing processes. For these two models sufficient conditions for the optimal type of policy, referring to the parameters of the models, are proposed.

An analysis of E-waste flows in China

In Europe, legislation about waste of electrical and electronic equipment (WEEE) recovery and recycling has been introduced in 2002, and corresponding legislation in the EU Member States was in place in August 2005 (EU-EC 2003). In the same period, China has been developing WEEE regulation as well. The main contribution to date to the Chinese legislative framework is the ‘Circular Economy Promotion Law of the People’s Republic of China’ that was approved on August 29, 2008, and came into force as of January 1, 2009. Both these legislative systems contain the Extended Producer Responsibility as a core concept, as well as a formal, and, in the case of China, centralised, recovery system. Given the conceptual similarities of legislation on WEEE, but striking differences in the product recovery systems in China and the EU, it is of interest to investigate if the existing recovery and recycling system in China actually fits the new legislation. Currently, there is anecdotal evidence that, in China, much of the WEEE flows into informal recycling channels such as secondhand market and manual recycling workshops. Not much is known otherwise because a formal governance system and official statistics collection do not exist yet. More particularly, the actual WEEE flow in China, or in particular cities, is virtually unknown, as is the relationship between collection, treatment, re-selling and disposal. This paper suggests a Markov chain model that allows for the analysis of the flow of WEEE through the reverse chain from point of collection through to final disposal. We analyse this system in its equilibrium state and investigate the impact of scenarios that reflect key elements of the new WEEE regulation in China. In addition, we offer a qualitative analysis of the various scenarios for the three dimensions of sustainability: people, planet and profit. This research offers specific suggestions to strengthen the Chinese WEEE recovery and recycling system that would bring the actual system more in line with the current policy.

Flexibility Focused Decision and Information Sharing Model for Product Recovery System

As a result of rapid progress in technology and the shrinking product lifecycles faster than ever before, has led creeping realization of additional profits by performing the effective and efficient product recovery operations at a world-class level quintessential. Realization of these motives is complex due to the multidimensional relationships associated with the quality, variety, timeliness, demand changes, and logical processing of product returns and inherent complexity of recovery process. Therefore an Enterprise System (ES) perspective will give us a scope to develop a profit oriented recovery process as a flexible system that can handle products with various options and greater return volume and structural variability. This paper proposes generic model to enterprises engaged in or to be engaged in product recovery processes. A semi or partially flexible decision process model that facilitates flexible decision and information sharing (DIS) functions in product returns. This DIS model leads us to conceptualize the evolution of information associated with a product returns and how it might be encapsulated by Reverse Enterprise System (RES) to improve its profit and system performance.

Butanol, ‘a superior biofuel’ production from agricultural residues (renewable biomass): recent progress in technology

AbstractThis article reviews bioconversion of plant materials such as wheat straw (WS), corn stover (CS), barley straw (BS), and switchgrass (SG) to butanol and process technology that converts these materials into this superior biofuel. Successful fermentation of low‒value WS makes butanol fermentation economically attractive. Simultaneous hydrolysis, fermentation, and product recovery has been successfully performed in a single reactor using WS and C. beijerinckii P260. Research on the production of butanol from other agricultural residues including CS, BS, and SG has steadily progressed. Use of several product‒recovery technologies such as liquid‒liquid extraction, gas stripping, perstraction, and pervaporation has been successfully applied in laboratory‒scale bioreactors. It is expected that these recovery technologies will play a major role in commercialization of this fermentation. By employing in line/in situ product‒recovery systems during fermentation, butanol toxicity to the culture has been drastically reduced. In addition to the use of low‒cost plant materials for the production of this biofuel, process integration is expected to play a major role in the economics of this product. © 2008 Society of Chemical Industry and John Wiley & Sons, Ltd

Flexible decision modeling of reverse logistics system: A value adding MCDM approach for alternative selection

The most favorable reverse manufacturing alternative arriving to collection centers has always been a key strategic consideration of any product recovery system. The nature of these decisions usually is considered to be multidimensional, interdisciplinary, complex, and unstructured due to lack of certainty in environment and information regarding time, quantity and quality of returns, etc. Fuzzy decision methodology provides an alternative framework to handle these reverse logistics system (RLS) complexities and to determine the decision strategies for best alternative selection for reprocessing. Designing a decision-making model for the same requires quantitative and qualitative evaluation based on criteria such as cost/time, legislative factors, environmental impact, quality, market, etc. Performance must be considered on the basis of these criteria to determine a suitable reverse manufacturing option depending on the expert opinion in this domain. In this paper, we propose a multiple criteria decision-making (MCDM) model based on fuzzy-set theory. The proposed model can help in designing effective and efficient flexible return policy depending on the various criteria. Further, companies can use this analysis as a strategic decision-making tool to develop fresh reprocessing facilities or efficiently use the already exiting facility. Finally, an example has been illustrated to highlight the procedural implementation of the proposed model. Further, this paper also makes an attempt to bring fuzzy-based flexible MCDM and reverse logistics together as a well-suited group decision support tool for alternative selections.

Sustainable Reverse Logistics for Distribution of Industrial Waste/Byproducts: A Joint Optimization of Operation and Environmental Costs

Byproducts and waste materials are potentially valuable inputs into a variety of industrial processes. Markets are being developed to capitalize on the use and reuse of these materials as inputs. The literature on reverse logistics analysis mostly concentrates on the end-of-life product recovery systems and mainly does not address the recovery process for waste/byproduct streams in an exchange network among industries. We have developed a reverse logistic model that minimizes the operational and environmental costs of exchanging waste and byproduct materials in a business-to-business network. The network contains firms, value-added process (VAP) centers (e.g., disassembly, recycling, or remanufacturing), disposal centers, and a virgin material market. The model takes the form of a mixed integer linear model. The model output contains the locations of the VAP centers and the material movement that minimizes the weighted sum of the operational and environmental costs. Because the problem is NP-hard, we developed a genetic algorithm (GA) to efficiently solve the model for large-sized problem instances. We demonstrated the modeling and solution approach for aluminum waste/byproducts in Los Angeles County. For this demonstration, we used data results from numerous past studies to assess the operational costs of waste/byproduct collection, processing, and movement. To estimate the environmental costs and parameters, we utilized published economic input-output results from previous studies. This model can be used as a guide for policies to encourage the development of sustainable supply networks.

Quality Based Model for Reverse Logistics: A KM View

Reverse Logistics comprises of all operations and decision making related to the reverse-flow of used products from customers to the manufacturers. It involves reuse of used products, remanufacturing or recycling, surplus inventory and packaging materials based on their configuration as well as condition. Excellent literature, related to quality modeling has been available for many years. A lot of discussion has taken place extolling the virtues of flexibility and its effect on the overall successful operation of enterprises. Considering in its generic form, quality based modeling can be applied to develop it as a flexible product recovery system. This paper examines the feasibility and practicality of applying a quality based self-assessment approach with a focus on flexibility for reverse logistic system improvements. It suggests that demonstration simulation models can play an important role in sharing the flexible work flow structures and the improvements in them. It is proposed that self-assessment based quality models to be developed to promote flexibility related issues, while dealing with the reverse logistics problems. One such model is presented and discussed in this paper.

An inventory approach for a Local Collection Point in reverse supply chains

Product recovery has received increasing attention in recent years. For a product recovery system, collection of used products is one of the key concerns. This article focuses on a special Local Collection Point (LCP) which handles a single type of used products. This special LCP can either to recover the used products and resell them in second-hand markets, or to deliver them to the Centralised Returns Center directly. For such a reverse system, we initiate and develop a joint inventory policy to improve its efficiency. The arrival process of used products, the handling/repairing time and the customer arrival process for repaired products are all assumed random. By formulating the system into a continuous-time Markov chain, the system's stationary distribution and its profit formulation are obtained. An algorithm for optimal inventory policies is developed. Managerial implications of the system characters and policies are discussed through the article.

Recovery of urokinase from integrated mammalian cell culture cryogel bioreactor and purification of the enzyme using p‐aminobenzamidine affinity chromatography

An integrated product recovery system was developed to separate urokinase from the cell culture broth of human kidney cells HT1080. Supermacroporous monolithic cryogels provided ideal matrices with respect to surface and flow properties for use as cell culture scaffold as well as for affinity chromatographic capture step of the enzyme in the integrated system. The urokinase was produced continuously in the reactor running for 4 weeks with continuous circulation of 500 ml of culture medium. The enzyme activity in the culture medium reached to 280 Plough units (PU)/mg protein. Cu(II)-iminodiacetic acid (IDA)-polyacrylamide (pAAm) cryogel column was used to capture urokinase by integrating with the gelatin-coupled pAAm-cryogel bioreactor for HT1080 cell culture. After removing the urokinase capture column from the integrated system the bound protein was eluted. The metal affinity capture step gave 4.5-fold purification of the enzyme thus achieving a specific activity of 1300 PU/mg protein. The enzyme eluate from Cu(II)-IDA-pAAm cryogel capture column was further purified on benzamidine-Sepharose affinity column. This step finally led to a homogeneous preparation of different forms of urokinase in two different elution peaks with a best urokinase activity of 13 550 PU/mg of protein. As compared to initial activity in the cell culture broth, about 26.2- and 48.4-fold increase in specific activity was achieved with enzyme yields corresponding to 32% and 35% in two different peak fractions, respectively. Native electrophoresis and SDS-PAGE showed multiple protein bands corresponding to different forms of the urokinase, which were confirmed by Western blotting and zymography.

Impact of uncertainties on recovery behavior in a remanufacturing environment

PurposeRemanufacturing of used products is an emerging business area, which is attractive from both an economic and an environmental point of view. Aims to investigate to what extent profit orientation in product recovery management will stimulate an environmentally conscious behavior in the sense that it promotes high recovery levels. This study also seeks to focus on a product recovery system where, in the context of extended product responsibility, a manufacturer of original products is also engaged in remanufacturing used products taken back from its customers.Design/methodology/approachFor this type of a closed‐loop supply chain the optimal recovery and production policy is evaluated. By a numerical analysis, it is shown how cost‐efficient decision making affects the product recovery behavior. In a sensitivity analysis it is evaluated how various problem determinants influence the preference for product recovery. Specifically, the impact of different sources of uncertainty is investigated.FindingsTaking advantage of the respective insights, it is discussed which measures can be taken to harmonize economical and environmental‐driven behavior in product recovery management. It is shown that uncertainty in returns and demands can be a considerable obstacle to follow a consequently environmental‐benign recovery strategy within a reverse logistics system.Research limitations/implicationsThe analysis in this paper is restricted to stationary demand and return patterns. In a non‐stationary situation the impact of uncertainties could be even stronger, since excessive returns might happen more often.Originality/valueFocuses on important issues in product recovery management.

Acetone butanol ethanol (ABE) production from concentrated substrate: reduction in substrate inhibition by fed-batch technique and product inhibition by gas stripping.

Acetone butanol ethanol (ABE) was produced in an integrated fed-batch fermentation-gas stripping product-recovery system using Clostridium beijerinckii BA101, with H(2) and CO(2) as the carrier gases. This technique was applied in order to eliminate the substrate and product inhibition that normally restricts ABE production and sugar utilization to less than 20 g l(-1) and 60 g l(-1), respectively. In the integrated fed-batch fermentation and product recovery system, solvent productivities were improved to 400% of the control batch fermentation productivities. In a control batch reactor, the culture used 45.4 g glucose l(-1) and produced 17.6 g total solvents l(-1) (yield 0.39 g g(-1), productivity 0.29 g l(-1) h(-1)). Using the integrated fermentation-gas stripping product-recovery system with CO(2) and H(2) as carrier gases, we carried out fed-batch fermentation experiments and measured various characteristics of the fermentation, including ABE production, selectivity, yield and productivity. The fed-batch reactor was operated for 201 h. At the end of the fermentation, an unusually high concentration of total acids (8.5 g l(-1)) was observed. A total of 500 g glucose was used to produce 232.8 g solvents (77.7 g acetone, 151.7 g butanol, 3.4 g ethanol) in 1 l culture broth. The average solvent yield and productivity were 0.47 g g(-1) and 1.16 g l(-1) h(-1), respectively.

Computational issues in a stochastic finite horizon one product recovery inventory model

Inderfurth [OR Spektrum 19 (1997) 111] and Simpson [Operations Research 26 (1978) 270] have shown how the optimal decision rules in a stochastic one product recovery system with equal leadtimes can be characterized. Using these results we provide in this paper a method for the exact computation of the parameters which determine the optimal periodic policy. Since exact computation is, especially in case of dynamic demands and returns, quite time consuming, we also provide two different approximations. One is based on an approximation of the value-function in the dynamic programming problem while the other approximation is based on a deterministic model. By means of numerical examples we compare our results and discuss the performance of the approximations.

Optimal control of a one product recovery system with leadtimes

In this paper a recovery system for a single product is investigated. Besides a remanufacturing and a manufacturing facility the system consists of one inventory for returned and recoverable items and one for serviceable items. Demands are satisfied from serviceable inventory, which can be replenished by remanufactured returned items, which are as good as new, or by new produced items. Additionally, there is the possibility of disposing of returned items. We determine the cost optimal manufacturing, remanufacturing and disposal rates for the system under the assumptions of a linear cost structure, a finite planning horizon and deterministic and dynamic demand and return rates. Thereby we study two classes of policies, one where backorders are forbidden and another one where they are allowed. In contrast to the existing literature positive leadtimes are considered.

A continuous time inventory model for a product recovery system with multiple options

Increasing environmental consciousness, limited availability of natural resources to manufacture new products, recovery quotas to avoid disposal, manufacturers assigned to be responsible for used products, and materials value of components included in returned products are incentives for product recovery. The fact that we now have two possible sources to service demand raises new operational questions. For instance, when is remanufacturing of used and returned products preferred to producing the requirements. Most production and inventory management models for reverse logistics are restricted to stationary demands and returns and do not address seasonal effects and product life cycles. Therefore, we consider a deterministic model with dynamic demands and returns. Then there might exist time periods where returns exceed demands and vice versa. The question has to be answered whether excess returns should be stored for future recovery or disposed of. In our work, there are different demand classes, e.g. different product qualities or different markets. This adds yet another aspect to be examined. It has to be determined for which demand class returns should be used. As a result returns can either be stored for later use for a certain demand class or being used instantly for another class. Demands have to be satisfied either from production or remanufacturing of returned products and returns not needed for recovery may be disposed of. In this paper we determine the optimal production, remanufacturing, and disposal policy for a linear cost model by applying Pontryagin's Maximum Principle.

Analysis of a product recovery system

The continuous growth in consumer waste in recent years has seriously threatened the environment. Environmentally conscious manufacturing and product recovery has become an obligation to the environment and to society. Many countries are contemplating regulations that force manufacturers to take back used products from consumers so that the components and materials retrieved from the products may be reused and/or recycled. We focus on a product recovery system in a remanufacturing system. Product recovery aims to minimize the amount of waste sent to landfills by recovering materials and parts from old or outdated products by means of recycling and remanufacturing. It should be considered when designing and managing the manufacturing systems. We propose a new analytical approach to evaluating the product recovery system with stochastic variability. This model applies the traditional inventory theory to the production/inventory management with consideration for disposal and return. The system is formulated by a discrete time Markov chain. It is composed of the states denoted by the number of the inventory, the transition probabilities between states and the costs associated with the transitions. Using the Markov analysis, we can calculate the total expected average cost per period exactly. Numerical examples are given to show the property of the management system and optimize the product recovery system.

Product recovery system – from a Pig

Product recovery system – from a Pig

Planning stability in a product recovery system

Recovery of used products is an issue of growing importance due to customer expectations and environmental regulation. As a consequence, companies need to adapt their material management taking into account inbound flows of used products. Corresponding inventory control models have been proposed in literature. In this paper we address the issue of planning stability in a product recovery context. To this end, we consider rolling horizon planning for a stock point facing stochastic demand and product returns. We analyze the impact of the return flow on planning stability and compare the system behaviour with a traditional production environment. We show that structural results derived for traditional inventory models remain valid in a product recovery context. Moreover we discuss counterintuitive effects resulting from interaction between planning stability and stock levels.

Optimal control of a one product recovery system with backlogging

In this paper a product recovery system for one product is investigated. The system contains one inventory for returned and recoverable items and one for serviceable items. Demands are satisfied from serviceable inventory where backlogging of demands is allowed. In addition, there is the possibility of disposal for the returned products. We assume deterministic but dynamic return and demand rates and a linear cost structure. The Pontryagin maximum principle is used to determine the optimal production, remanufacturing and disposal policy.