A review of the valorization and management of industrial spent catalyst waste in the context of sustainable practice: The case of the State of Kuwait in parallel to European industry

Identifying the socioeconomic determinants of industrial hazardous waste generation: South Korea as a case study

The South Korean government has set an ambitious target to reduce industrial hazardous waste (IHW) as part of its transition towards a circular economy. Moreover, effective management of IHW within the country has become crucial, given that IHW trade is regulated by the Basel Convention. Despite the urgent need for well-founded environmental policies, there is a lack of essential information on the characteristics and determinants of IHW generation, which hinders the effectiveness of existing IHW policies. To address this information gap, this study developed a South Korean extended IHW input-output model for 2008 and 2018 to characterize IHW generation and applied structural decomposition analysis to identify the socioeconomic determinant of change of IHW generation. The results reveal that consumption, export, and direct IHW intensity change of 'Chemical', 'Electronic and electrical equipment', 'Basic metal', and 'Other service' emerge as dominant determinants for IHW growth. Conversely, technology change, including technological structure change and direct IHW intensity change, of 'Basic metal' and 'Other service' is the key driver for IHW reduction. In addition, an intriguing aspect of the study relates to the supply chain's influence on IHW generation. The indirect growth of IHW resulting from expanding exports and consumption contributes nearly twice as much to the overall increase in IHW as direct IHW growth. These valuable insights pave the way for the South Korean government to establish holistic and customized environmental policies regarding IHW. It emphasizes the importance of considering expanded global system boundaries, technological advancements, and purchasers' consumption patterns as dominant factors in formulating these policies. Furthermore, this study not only provides crucial guidance for the government's decision-making but also suggests strengthening environmental management and monitoring practices.

On the implementation of the circular economy route for E-waste management: A critical review and an analysis for the case of the state of Kuwait

Electronic waste (e-waste) has become one of the major causes of environmental concerns due to its large volume, high generation rate and toxic environmental burdens. Recent estimates put e-waste generation at about 54 million tonnes per annum with figures reaching approximately 75 million tonnes per annum by 2030. In this manuscript, the state-of-the-art technologies and techniques for segregation, recovery and recycling of e-waste with a special focus on the valorisation aspects of e-plastics and e-metals which are critically reviewed. A history and insight into environmental aspects and regulation/legislations are presented including those that could be adopted in the near future for e-waste management. The prospects of implementing such technologies in the State of Kuwait for the recovery of materials and energy from e-waste where infrastructure is lacking still for waste management are presented through Material Flow Analysis. The information showed that Kuwait has a major problem in waste accumulation. It is estimated that e-waste in Kuwait (with no accumulation or backlog) is generated at a rate of 67,000 tpa, and the imports of broadcasting electronics generate some 19,428 tonnes. After reviewing economic factors of potential recovered plastics, iron and glass from broadcasting devices in Kuwait as e-waste, a total revenue of $399,729 per annum is estimated from their valorisation. This revenue will open the prospect of ventures for other e-waste and fuel recovery options as well as environmental benefits and the move to a circular economy.

Accessing Metals from Low-Grade Ores and the Environmental Impact Considerations: A Review of the Perspectives of Conventional versus Bioleaching Strategies

Mining has advanced primarily through the use of two strategies: pyrometallurgy and hydrometallurgy. Both have been used successfully to extract valuable metals from ore deposits. These strategies, without a doubt, harm the environment. Furthermore, due to decades of excessive mining, there has been a global decline in high-grade ores. This has resulted in a decrease in valuable metal supply, which has prompted a reconsideration of these traditional strategies, as the industry faces the current challenge of accessing the highly sought-after valuable metals from low-grade ores. This review outlines these challenges in detail, provides insights into metal recovery issues, and describes technological advances being made to address the issues associated with dealing with low-grade metals. It also discusses the pragmatic paradigm shift that necessitates the use of biotechnological solutions provided by bioleaching, particularly its environmental friendliness. However, it goes on to criticize the shortcomings of bioleaching while highlighting the potential solutions provided by a bespoke approach that integrates research applications from omics technologies and their applications in the adaptation of bioleaching microorganisms and their interaction with the harsh environments associated with metal ore degradation.

Fungal bioleaching of metals from refinery spent catalysts: A critical review of current research, challenges, and future directions

Petroleum refining operations such as hydroprocessing and fluid catalytic cracking (FCC) generate huge quantities of spent catalysts containing toxic and valuable metals (Ni, V, Mo, Co, W, Al, etc.), the management of which is a serious environmental issue. Besides environmental concerns, the different metals present in the spent catalysts are also a valuable commodity to modern industries. Therefore, these spent catalysts also provide an opportunity to use it as a source of value to the refiners. In recent years, a biotechnological based leaching process 'bioleaching' has emerged as a promising eco-friendly technique for the extraction of metals from these refinery spent catalysts. Among various bioleaching agents such as archean, bacterial, or fungi, the process mediated by the fungi (Aspergillus niger, Penicillium simplicissimum, and many others) is gaining attention owing to the high metal extraction ability of the various fungal produced metabolites (organic acids) under moderately acidic conditions. Furthermore, the ability of these fungi to withstand wide process conditions (pH, spent catalyst concentration, substrate types, etc.), high metal toxicity and use of low-cost organic substrate make them an ideal candidate for bioleaching. In this review article, we shed light on the role and mechanisms of fungi involved in extracting different metals from spent hydroprocessing and FCC catalysts. Key process parameters that affect the efficiency of fungal based bioleaching are discussed. The techno-economic challenges associated with the process are elaborated, and the needed future research directions to promote its commercial applications are highlighted. Based on our analysis, it can be argued that the fungi bioleaching has potential, however, some challenges (slower kinetics, and health and safety) should be addressed before the process can be scaled up for the commercial application.