Recycle Mode Research Articles

Water Reuse via Membrane Technology: A Case Study for Producing Cooling Water from Soft Drink Wastewater

High volumes of water are used in the soft drink industry, where purification can be achieved via membrane technology, allowing it to be reused in operating cooling towers, steam boilers, and closed-loop systems. In this study, ultrafiltration (UF) and nanofiltration (NF) were applied to produce reclaimed water for cooling towers. In experimental studies conducted under a total recycle mode of operation, two UF membranes with molecular weight cut-offs (MWCO) of 10 kDa and 5 kDa, and one NF membrane were tested. The transmembrane pressure was set to 2 bars for UF and 4 bars for NF. Considering the water quality criteria for cooling towers, removal efficiencies were calculated for total suspended solids (TSS), turbidity, and chemical oxygen demand (COD). TSS and turbidity removal rates were 100% for both UF and NF; however, COD removal rates varied. In UF, feed and permeate COD concentrations were 718 - 796 mg/L and 255 - 286 mg/L, corresponding to a removal efficiency of 64-65%. On the other hand, in NF, the feed and permeate COD concentrations were 207 mg/L and 147 mg/L, indicating a 29% removal. Flux decline was not severe; it ranged from 10% to 20%. It was revealed that further treatment is required to meet the COD criteria of 75 mg/L for cooling towers.

Optimal strategies in electric vehicle battery closed-loop supply chain considering government subsidies and echelon utilization

This study examines an electric vehicle battery closed-loop supply chain including a battery manufacturer and a retailer, with a focus on echelon utilization and remanufacturing of waste electric vehicle battery. Optimal pricing strategies and technological effort decision of the supply chain members are derived based on a Stackelberg game model. Three government subsidy policies are considered to promote recycling and reuse of waste electric vehicle batteries, namely, no subsidies, production research and development (R&D) subsidies and recycling subsidies, respectively. Results show that both echelon utilization and recycling subsidies can notably contribute to recycling rate of waste electric vehicle batteries. While echelon utilization boosts the profit of retailer and the whole supply chain, it may have a negative impact on manufacturer's inclination to remanufacturing and its profit. Subsidies for production research and development are preferred by the supply chain and its members from the profit-oriented perspective. Further analyses are conducted under hybrid strategies: hybrid government subsidy policy and hybrid recycling mode. Results show that hybrid strategies could significantly increase the demand and recycling volume, thus positively affecting the profitability of the entire closed-loop supply chain. Our study comprehensively considers the game relationships among manufacture and retailer, enhancing the efficiency of recycling and profitability while also providing a theoretical basis for the government to formulate reasonable subsidy policies.

How to Choose Recycling Mode between Monopoly and Competition by Considering Blockchain Technology?

Enterprises adopting a circular economy approach can effectively solve the severe situation of resources and the environment, and recycling is considered an effective means to solve environmental issues. Simultaneously, blockchain technology (BT) has been used to enhance product quality trust. However, there is limited literature on how to choose between monopolistic and competitive recycling modes by considering BT. This paper uses a game involving a manufacturer, a retailer, and a third-party recycler (TPR) in a closed-loop supply chain (CLSC). The retailer can recycle on itself and compete with the TPR for recycling used products. The results show that BT adoption could increase the recycling rate and demand for remanufactured products. BT benefits the firms in the CLSC when they control usage costs, regardless of whether competitive recycling mode is used or not. In addition, whether BT is adopted or not, CLSC firms prefer competitive recycling mode only when the competitive intensity exceeds a specific threshold. Moreover, choosing an appropriate recycling mode can alleviate the negative impact of BT on the environment, then an all-win result can be obtained for CLSC firms, consumers, and society. These results can give suggestions for managers to optimize their supply chains regarding adopting BT and implementing recycling mode. In the future, we can expand our research on the transfer price of used products, the positive and negative effects of BT, and BT cost-sharing strategies.

Optimal decisions and coordination of a supply chain in the hybrid recycling mode with traceability and fairness concern

Considering the case of recycling competition between a manufacturer and a retailer, we construct game models under centralised and decentralised decision-making with or without fairness concern, respectively. By comparatively analysing the optimal decisions and profits under the three models, we design an improved two-part tariff contract to realise supply chain coordination. We have the following findings: First, in the supply chain with traceability, consumers’ preference for traceability and the impact of traceability on recycling are not only beneficial to the environment but also to each enterprise. Second, the retailer’s concern for fairness can harm the profits of the manufacturer and system. Moreover, the retailer’s disproportionate focus on fairness of the distribution of revenues hinders the introduction and development of the traceability system, leading to lower recycling volume and demand. Third, the traceability system is most efficient under centralised decision-making, attaining the highest traceability level, recycling volume, and system profit. The retail price and manufacturer’s recycling price are lower than those under decentralised decision-making. Our findings also suggest that improved two-part tariff contract can enhance the chain members’ performance. While fairness concern and fierce recycling competition hinder implementation of the coordination mechanism, and improved traceability facilitates the attainment of coordination.

How can the recycling of power batteries for EVs be promoted in China? A multiparty cooperative game analysis

While electric vehicles (EVs) are developing at a high speed in China, the power battery market is facing a decommissioning peak. The problem is that the recycling situation of domestic power batteries is not ideal, partly due to neglect by consumers. By considering the recycling system, mode, and policy of China’s EV power batteries, we construct a tripartite evolutionary game model of the government, consumers and EV manufacturers; analyse the stable strategy adjustment mechanisms of tripartite participation in this recycling cooperation game; and simulate the tripartite evolutionary game. The results show that when the initial willingness of the government, consumers and EV manufacturers to recycle power batteries is not strong, the government takes the lead, driving EV manufacturers and consumers to participate in power battery recycling. When the government, consumers and EV manufacturers have medium or high levels of initial willingness, the government evolves and chooses a nonregulation strategy. In addition, by simulating the impact of changes in consumer-related influencing factors on this tripartite evolutionary game, we find that subsidies for recycling power batteries are a key factor affecting consumers’ strategy choices and that boosting recycling compensation for consumers can improve their enthusiasm to participate in such recycling. Therefore, to improve the recycling of power batteries for EVs, in terms of both efficiency and percentage of deployment, the Chinese government should strengthen public education on power battery recycling, further integrate informal recycling channels, and balance the distribution of profits among consumers for recycling compensation.

Recycling Mode Choice in a Textile and Apparel Closed-Loop Supply Chain considering Blockchain

The development of the textile and apparel (T&A) industry has led to an increasing focus on recycling used products. Remanufactured product quality raises consumer concerns, and blockchain can effectively solve this problem. We establish a closed-loop supply chain (CLSC) in which a manufacturer, a retailer, or a third-party recycler collects used T&A products to examine the most efficient recycling mode with and without blockchain and the impact of blockchain on CLSC decisions. The results show that (1) if the manufacturer’s recycling cost coefficient is relatively low, used T&A products are collected directly by the manufacturer. Otherwise, the responsibility for recycling used T&A products falls to the retailer or the third-party recycler. It is noteworthy that the manufacturer’s choice of recycling mode remains unchanged whether a blockchain is implemented or not. (2) The implementation of blockchain by the manufacturer and the retailer can increase profits and consumers also benefit when the cost of validating blockchain units remains below a certain threshold. (3) When the recycling cost coefficient exceeds a certain threshold, the implementation of blockchain increases prices and recycling rates. These findings offer CLSC members’ management insights into how to select the optimal recycling mode and the consequences of implementing blockchain.

Separation of heavy metals from dilute solutions using D2EHPA carrier fixed onto the outer surface of coaxially electrospun core-sheath fibers

In this study, porous membranes based on core-sheath fibers covered with fixed carriers were prepared by coaxial electrospinning for the separation of heavy metal ions from dilute solutions. Cellulose triacetate (CTA) and an extractant di(2-ethylhexyl)phosphoric acid (D2EHPA) were mixed to prepare a sheath-layer solution and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) was adopted to prepare a core-layer solution for electrospinning. The morphological and textural properties as well as chemical composition of the fabricated core-sheath fibers were first analyzed to determine the optimal preparation conditions. The ability and selectivity of such fixed D2EHPA carriers were evaluated via the adsorption of Zn2+, Cu2+, and Ni2+ ions from dilute solutions. Dynamic tests revealed that the adsorption of metal ions on the core-sheath fibrous membrane made of 52 wt% PVDF-HFP, 18 wt% D2EHPA, and 30 wt% CTA (on a dry basis) reached equilibrium within 8 h. As expected, all adsorption isotherms at specific equilibrium pH values were well described by the Langmuir equation, ascribed to the chemical reaction nature between metal ions and D2EHPA carrier. The crossflow permeation-adsorption tests of a multi-metal solution in a total recycling mode revealed the adsorption selectivity of Zn2+ over Cu2+ and Ni2+, as observed in conventional liquid–liquid extraction. Four repeated adsorption-regeneration experiments revealed an adsorption efficiency beyond 95 % relative to the first route, demonstrating the satisfactory reusability and stability of the as-prepared core-sheath fibrous membranes for this purpose.

Analysis of Packaging Recycling Mode in Chinese Express Delivery Industry

With the widespread adoption of smartphones and Internet technology, China's express delivery industry has experienced explosive growth. Concurrently, this surge has resulted in the substantial generation of express packaging waste, leading to substantial resource wastage and environmental pollution. There is a need to improve reuse of express packaging in order to reduce the express packaging garbage, and recycling constitutes a crucial step in the reutilization of express packaging materials. The purpose of this study is to investigate the recycling patterns in Chinese Express Industry. This study employed a systematic literature review synthesis method to assess trends, identify gaps, and recommend future approaches to enhance the reuse of express packaging. The focus was on analysing the recycling status, influencing factors, and improvement strategies related to express packaging recycling. Research findings indicate that the recycling of express packaging is confronted with challenges such as high recycling costs and low recycling efficiency in China. Therefore, this paper proposes the combination of low-cost standardized packaging for express delivery, along with consumer awareness of environmental protection and an efficient recycling system, can significantly boost the recycling and reutilization of express delivery packaging. This study will contribute to enhancing the reusability and recycling of express packaging by improving the recycling process, thereby reducing the generation of express waste and minimizing resource wastage.

Tuning selectivity in low-temperature Fischer-Tropsch synthesis by applying gas recycle mode

While hydrocarbons production by Fischer-Tropsch synthesis (FTS) is widely recognized, commercial interest in FTS products is mainly constrained by oil prices. The FTS-derived fuels, although higher quality and greener, cannot currently compete with cheaper fossil fuels, motivating to shift the FTS products distribution to higher value-added chemicals, such as olefins-C5+. The high olefin selectivity in FTS over Co-based catalysts is usually ascribed to Co2C on the catalyst surface with its inherent deficiencies. This study demonstrates a novel approach to alter low-temperature FTS selectivity by applying off-gas recycling. At slow gas recycling rates, C19+ selectivity increases due to re-adsorption and re-incorporation into the growing chain of gaseous olefins from the off-gas. High-intensity gas recycling facilitates C5+ olefin vapors removal from the reactor by enhanced gas flow with their subsequent cut-off in the cold trap, thus reducing residence time of condensed olefins and probability of their secondary reactions.

Pricing and Quality Improvement Decisions in the End-of-Life Vehicle Closed-Loop Supply Chain Considering Collection Quality

This article investigates the effects of end-of-life vehicle (ELV) collection quality on pricing and quality improvement decisions for different recycling modes by considering the discrepant heterogeneity of ELVs due to individual utilization and component degradation. This article examines the pricing and quality improvement decisions within an ELV closed-loop supply chain with heterogeneous collection quality that includes one manufacturer and one retailer. Stackelberg game models are formulated to examine the equilibrium solution in relation to three recycling modes (ELVs are recycled by the manufacturer, retailer, and third-party). We study the pricing and quality improvement decisions of ELV recycling to probe the influential mechanism of ELV collection quality under different recycling scenarios. The numerical experiment provides empirical guidance for ELV recycling management practices. Results show that wholesale and retail prices decrease with increasing ELV collection quality. In addition, there is a positive correlation between collection quality and the overall performance of the ELV supply chain. This article enhances better understanding on pricing and quality improvement decision-making in relation to ELV collection quality and helps participants in the closed-loop supply chain to determine the best recycling mode.

Research on blockchain-based recycling mode of used power batteries led by the government

With the rapid development of the new energy automobile industry, the environmental safety problems brought by a large number of retired and used batteries have become increasingly prominent. Based on the analysis of the existing market, this paper summarizes the existing recycling mode of manufacturers as the main body, automobile dealers as the main body, and third parties as the main body, proposes a blockchain-based government-led strategic recycling alliance waste and new energy power battery recycling system model, and builds a waste power battery recycling cost model based on cost accounting. The problems encountered in reverse supply chain recycling and relevant countermeasures are proposed, which has important theoretical and practical significance for promoting the development of waste and new energy power battery recycling industry in Shandong Province.

Recycling Strategy of Green Closed-Loop Supply Chain Under Urban and Rural Low-Carbon Planning

Abstract The low-carbon ecological city aims to harmonise sustainable urban development with low-emission planning approaches. Emissions from business production processes are central to low-carbon planning. This paper explores three closed-loop supply chain recycling models - manufacturer, retailer, and third-party -considering carbon trading and emission reduction technology investment. Respective Stackelberg game models are developed incorporating carbon emission reduction costs, recycling costs, carbon trading price, emission intensity, and recycling price. The influence of these variables on carbon emission reduction and profit is examined through numerical analysis. Results indicate the government’s free carbon quota does not impact per-unit carbon reduction or manufacturer profit, nor optimal recycling mode selection. Under specific remanufacturing emission intensity and production cost saving conditions, carbon quota trading can substantially incentivise manufacturers to invest in emission reduction and recycling. With carbon trading and emission reduction technology investment, manufacturer recycling optimises economic and environmental benefits when remanufactured products provide high production cost savings. This fosters sustainable development supporting low-carbon planning.

Efficient wastewater treatment in petroleum refineries: Hybrid electro-fenton and photocatalysis (UV/ZnO) process

In this study, a new hybrid system composed of a photo-catalysis (UV/ZnO) process combined with an electro-Fenton (EF) process equipped with a micro porous graphite air diffusion cathode (MPGADC) was used to treat petroleum refinery wastewater (PRW). The hybrid system was operated in a batch recycle mode and its performance was investigated and optimized using a response surface methodology (RSM). Three operating parameters affecting on the removal efficiency (RE%) of chemical oxygen demand (COD) were investigated including current density (2–10 mA/cm2), ZnO dosage (0.05–0.35 g/L), and Fe2+concentration (0.05–0.15 mM). Results showed that the optimum operating conditions can be achieved using a current density of 6.44 mA/cm2, with ZnO dosage of 0.35 g/L, and concentration of Fe2+ ions at 0.05 mM in which RE% of 90.15% was obtained with requiring a total electrical energy consumption (EECT) of 19.102KWh/m3. Furthermore, analysis of variance (ANOVA) exhibited a high value of determination coefficient (R2) close to 98.24% indicating a satisfactory fit between the obtained regression model and the experimental results. Moreover, ANOVA results revealed that current density has the most significant effect on RE% with a contribution of 52.41% followed by ZnO dosage and Fe2+ concentration both of them with a contribution of 11.64%. The comparison between the individual photo-catalysis process and hybrid process showed that RE% increases from 77.83% to 90.15% making an enhancement by 15.83% in RE% while EECT decreased from 27.171to 19.102KWh/m3 making a reduction by 29.7% in EECT. Hence, combining EF with photo-catalysis process improves the efficiency and reduced the required energy in comparison with the individual photo-catalysis process. Therefore, the combined process could be considered as an alternative, sustainable, green and cost-effective method for treatment of refinery wastewaters.

Optimization of carton recycling site selection using particle swarm optimization algorithm considering residents' recycling willingness.

With the development of the express delivery industry, how to increase the recycling rate of waste cartons has become a problem that needs to be solved. Recycling enterprises began to provide the new recycling mode, door-to-door recycling services, to residents with waste cartons. In this article, we constructed a site selection model for a carton recycling site with the aim of maximizing total profits. Considering the residents' recycling willingness and the government subsidy earned through the contribution to carbon emission reduction, this model achieves the task of site selection and unit price fixation for carton recycling. We used the particle swarm optimization (PSO) algorithm to solve the model and compared it with the genetic algorithm (GA) for validity testing. PSO algorithm was also used to carry out sensitivity analysis in this model. The proposed model and the results of the sensitivity analysis can be used for decision-making in recycling enterprises as well as for further research on waste recycling and reverse logistics.

MILD-Oxy Combustion Characteristics of Pulverized Coal Affected by Oxidizer O2 Concentrations under Dry and Wet Recycle Modes

MILD-Oxy Combustion Characteristics of Pulverized Coal Affected by Oxidizer O₂ Concentrations under Dry and Wet Recycle Modes

An indigenous tubular ceramic membrane integrated bioreactor system for biodegradation of phthalates mixture from contaminated wastewater.

Endocrine-disrupting phthalates (EDPs) are widely used as plasticizers for the manufacture of different plastics and polyvinyl chloride by providing flexibility and mechanical strength. On the other hand, they are categorized under priority pollutants list due to their threat to human health and the environment. This study examined biodegradation of a mixture of dimethyl, diethyl, dibutyl, benzyl butyl, di-2-ethylhexyl, and di-n-octyl phthalates using a CSTB (continuous stirred tank bioreactor) operated under batch, fed-batch, continuous, and continuous with biomass recycle operation modes. For operating the CSTB under biomass recycle mode, microfiltration using an indigenous tubular ceramic membrane was employed. Ecotoxicity assessment of the treated water was carried out to evaluate the toxicity removal efficiency by the integrated bioreactor system. From the batch experiments, the EDPs cumulative degradation values were 90 and 75% at 1250 and 1500mg/L total initial concentration of the mixture, respectively, whereas complete degradation was achieved at 750mg/L. In the fed-batch study, 93% degradation was achieved at 1500mg/L total initial concentration of the mixture. In continuous operation mode, 94 and 85% degradation efficiency values were achieved at 43.72 and 52.08mg/L⋅h inlet loading rate of phthalate mixture. However, continuous feeding with 100% biomass recycle revealed complete degradation at 41.67mg/L⋅h inlet loading rate within the 84h operation period. High seed germination index and low mortality percentage of brine shrimps observed with phthalate degraded water from the integrated bioreactor system revealed its excellent potential in the treatment and toxicity removal of phthalates contaminated environment.

Impacts of sales mode and recycling mode on a closed-loop supply chain

This paper forms a closed-loop supply chain (CLSC) consisting of a manufacturer and a retailer, within which the retail channel or dual-channel sales mode is chosen for selling products while the manufacturer, retailer or hybrid recycling mode is chosen for collecting used products. Based on different sales modes and recycling modes, six-game theory models are formulated to derive the optimal pricing and recycling rate decisions. Through the model comparisons and the numerical analysis, we investigate the strategies for choosing the optimal sales mode and the optimal recycling mode. We find that the customers, the environment and the manufacturer always prefer the dual-channel sales mode. However, the retailer prefers the dual-channel (retail channel) sales mode when the discount coefficient of demand is relatively low (high). Moreover, the customers, the environment and the manufacturer prefer the hybrid (retailer) recycling mode when the competing intensity of recycling is relatively low (high). However, the retailer prefers the hybrid (retailer) recycling mode in the retail channel CLSC while preferring the hybrid (manufacturer) recycling mode in the dual-channel CLSC when the competing intensity of recycling is relatively low (high).

Dynamic Two‐Phase Flow Modeling of Melt Segregation in Continental Crust: Batholith Emplacement Versus Crustal Convection, With Implications for Magmatism in Thickened Plateaus

AbstractMagmatic processes in the continental crust such as crustal convection, melt ascent, magma emplacement, and batholith formation are not well understood. We solve the conservation equations for mass, momentum, and energy for two‐phase flow of melt and solid in 2D, for a thick continental crust heated from below by one or several heat pulses. A simplified binary melting model is incorporated. We systematically vary (a) the retention number, characterizing melt mobility, (b) the intensity of heat pulses applied at the bottom, and (c) the density of the solidified evolved rock. Two characteristic modes are identified: (a) in the “batholith emplacement mode,” segregation is sufficiently strong allowing melts to separate from the convective flow. This melt freezes to form buoyant SiO2‐rich layers. (b) In the “convective recycling mode,” melts are formed in the lower crust, rise together with the hot rock with little segregation, freeze at shallow depth but are partly recycled back to the lower crust where they remelt. Phase‐change‐driven convection dominates. Mode (a) is favored by high heat input, multiple heat pulses, high melt mobility, and low density of the evolved rock. Mode (b) is favored by less intense heating, less melt mobility, and denser evolved rocks. A scaling law is derived based on the thermal, melt, and compositional Rayleigh numbers and the retention number. The Altiplano‐Puna low‐velocity zone (LVZ) could represent the batholith emplacement mode with buoyant and voluminous magmas causing intense volcanism. The Tibetan LVZ is not associated with intense volcanism and might represent the convective recycling mode.

A novel hybrid system for continuous biodegradation and toxicity removal of low molecular weight phthalates

Dimethyl phthalate (DMP) and diethyl phthalate (DEP) are environmental toxicants that can interfere with the endocrine system and cause adverse health impacts by mimicking the natural hormone activity. The present study focused on the biodegradation of DMP and DEP mixture by Cellulosimicrobium bacteria in a bioreactor under batch, fed-batch, continuous and continuous with biomass recycle modes. Biomass recycling was done followed by microfiltration using an indigenous low-cost tubular ceramic membrane. Under the batch mode of operation, maximum degradation values of 85 % and 58 % were observed at 1000 and 2000 mg/L initial concentrations of DMP and DEP, respectively, in mixture, whereas, complete degradation was achieved in the fed-batch system at the same initial concentrations. In continuous operation mode at 24 h hydraulic retention time, complete degradation was achieved for all inlet DMP and DEP concentrations. The biomass recycle operation mode was found to be the best strategy owing to complete degradation of the phthalates, even at very high inlet concentrations and at a short hydraulic retention time (HRT) of 16 h. A high germination index (GI) value of 91.86 % and 0 % brine shrimp mortality further demonstrated the potential of the biomass recycle system for the treatment of phthalate containing wastewater.

Impacts of sales mode and recycling mode on a closed-loop supply chain

Statement of Removal Due to a technical issue, this article incorrectly published in the International Journal of Systems Science instead of the International Journal of Systems Science: Operations & Logistics. Therefore, this article has been removed from International Journal of Systems Science and republished in the International Journal of Systems Science:Operations & Logistics. The article is now available in the link: https://doi.org/10.1080/23302674.2023.2221076 Article title: Impacts of sales mode and recycling mode on a closed-loop supply chain Authors: N.Wan Journal: International Journal of Systems Science Version of Record Published Online: 06 April 2023 DOI: http://doi.org/10.1080/00207721.2023.2197434