Journal of the Indian Institute of Science最新文献

Plastic waste is a growing concern globally on account of the increasing use of plastic worldwide, compounded by single-use applications, poor waste collection and management practices, and its consequent leakage into the environment. In addition, plastics are derived from non-renewable fossil resources, and their growing demand is also partly responsible for greenhouse gas emissions and climate change. The aim of this paper is to explore the potential of plastic waste as a material resource, and thermocatalytic pyrolysis as a recycling process, to produce aliphatic and aromatic hydrocarbons, which are important chemical intermediates for various industries. We show that plastic pyrolysis can achieve a high yield of liquid hydrocarbons (~ 80%) with a suitable distribution of aliphatic and aromatic compounds, by using different pyrolysis conditions and a catalyst. Specifically, this paper demonstrates the possibility of deriving two key classes of hydrocarbons, i.e., aliphatic (C10–C20 hydrocarbons) and aromatic hydrocarbons (xylene, toluene and benzene derivatives) with a yield of ~ 80% liquid hydrocarbons via catalytic pyrolysis. We also briefly discuss the challenges and opportunities, and the environmental and economic implications.

Biomass as an energy source for the millions of under-privileged families in rural and semi-urban settings in India and over a large part of the World remains an ever-present necessity that remains acknowledged only in scholarly publications. Modern solutions for the combustion applications even when available are allowed to remain without adoption. This has resulted in attempts to deal with commercial applications as well as larger scale drying of perishables with novel techniques for fast drying while preserving the quality of dried products as approaches to make waste biomass use valuable to the society. This article provides a very brief history of improved cook stove development and dissemination both of fixed and portable forms with further evolution of fan-based technologies—batch and continuous combustion modes aimed at higher combustion efficiency and lower emissions. The role of biomass quality that has remained unaddressed all along will be discussed with solution strategy for production and commercial supply of solid fuels. That biomass fraction of urban solid waste is largely a renewable biomass source and can be treated to obtain quality biomass-based fuels for societal use is discussed in some detail and is argued to be a continuous source of supply of fuels to meet the energy demands.

Wetlands (lakes, tanks, ponds, etc.), transitional lands linking hydrologically the terrestrial ecosystem with aquatic ecosystems with biophysical interactions, are the most productive and diverse ecosystems and provide numerous ecological, economic, and social benefits for human well-being. These vital ecosystems sustain ecological processes to provide services such as nutrient cycling, water purification, reducing pollution, carbon sequestration, groundwater recharge, provision of fish, fodder, fuel, and water, flood reduction, erosion control, aquatic biota habitats, education opportunities, aesthetics, and recreation. However, due to globalization, these fragile ecosystems are vulnerable to unplanned developmental activities and rapid urbanization, leading to large-scale land cover changes and hydrologic regimes. The sustained inflow of untreated wastewater (from the industrial and domestic sectors) into wetlands has altered the chemical integrity, which necessitates inventorying, mapping, and regular wetland monitoring to evolve conservation strategies. Integrating spatial and non-spatial data, analysis, and visualization with decision models through decision support systems enables informed decisions. In this context, the Bangalore Lake Information System (BLIS) is designed with information on water quality, biodiversity (microalgae, zooplankton, ichthyofauna, macrophytes, and birds), threats (encroachments, inflow of untreated sewage, etc.) and ecosystem services of lakes in Bangalore, Karnataka State, India. Rapid large-scale land use changes have resulted in an alteration in the hydrologic regime, the loss of habitats, and the disappearance of native species. BLIS empowers decision-making through knowledge of lake distribution in terms of the physical, chemical, and biological aspects and the value of ecosystem services, which is crucial for evolving strategies for prudent management of water bodies in Greater Bangalore.

The paper focuses on review of developments in low carbon building technologies since the inception of ASTRA/CST. Five decades of R&D and dissemination of alternative building technologies has been traced in three phases. The narrative highligts many building technologies developed, R&D work through doctoral programmes and sponsored research, capacity building and design of special courses. The impact of the low-C technologies on the construction industry, emission reduction and public investment on these technologies have been highlighted. The ASTRA/CST work ultimately resulted in over 4 million tonnes of carbon emission reductions. Apart from training many building professionals and the work provinded innovative topics for the doctoral reseach programmes at Indian Institute of Science.

PFAS, ubiquitous in various industrial and consumer products, poses significant environmental and health concerns due to their persistence and bio-accumulative nature. This review hence discusses sources, potential exposure pathways, ecological and health impacts of PFAS. The review further explores various PFAS degradation and removal technologies, including bioremediation, chemical oxidation, advanced oxidation processes, adsorption, membrane filtration, plasma-based degradation, thermal treatment, and hydrolysis, highlighting their potential applications in addressing PFAS contamination. It is observed that significant obstacle is the inefficiency of many technologies in eliminating short-chain PFAS, which are more environmentally stable than long-chain counterparts, raising concerns about converting long-chain PFAS into short-chain forms, during degradation process. Moreover, thorough toxicological assessments are crucial to verify the effectiveness of each technology and prevent the generation of new PFAS or toxic byproducts during treatment. Currently, there exists a pressing societal demand exists to explore affordable and environmentally safe PFAS degradation technologies, minimizing negative environmental repercussions, and being feasible for large-scale field applications. Also, there is a need to establish maximum allowable contamination level data for PFAS in drinking water, treated water for reuse and soil, for Indian context. Overall, this review provides insights into understanding PFAS contamination issues and highlights the potential of degradation technologies in addressing this pressing environmental challenge.

Dumpsite remediation has become a crucial aspect of sustainable waste management. This study reviews the current state of knowledge on dumpsite remediation, identifying key gaps in the literature. It explores site investigation, characterization of dumpsites, and remediation techniques, with a focus on dumpsite mining and rehabilitation measures. In the context of dumpsite mining, the study examines the potential recoverable fractions, challenges in recyclability and processing, and the economic aspects of mining operations. For rehabilitation, it discusses the importance of slope stabilization, leachate and gas management, and long-term monitoring strategies. Given the lack of specific criteria for selecting appropriate remediation methods based on site requirements, the study proposes criteria for choosing sustainable approaches. Additionally, case studies are reviewed to demonstrate the successful application of dumpsite remediation for environmental protection and containment, as well as the potential of mining to generate value-added products within a circular economy perspective. However, challenges observed in the case studies, such as heterogeneous waste composition, technological limitations, and economic viability, present significant barriers. The study suggests that overcoming these challenges requires legislative support, infrastructure development, and stakeholder collaboration. The paper concludes with recommendations for advancing circular economy solutions, emphasizing the need for integrated waste management, innovative technologies, and cooperative efforts to achieve sustainable waste management.

The extensive use of fossil resources in fuel production, leading to the emission of high levels of anthropogenic gases and atmospheric degradation, is a cause for concern. Consequently, exploring substitutes for fossil fuels and renewable raw materials in the production of sustainable fuels has become a critical area of research. Over the past decades, significant efforts have been dedicated to researching renewable and eco-friendly fuels from diverse sources. A prominent avenue of investigation involves biodiesel production from fats and oils through the uncomplicated process of transesterification, utilizing acid–base catalysts. The design of these catalysts is pivotal, not only for ensuring efficient conversion but also for achieving high biodiesel selectivity and enhancing the techno-economics of the process. Strategic selection of raw materials, such as non-edible fats and oils, is crucial to elevate the process's importance and mitigate potential conflicts between food and fuel resources. Furthermore, catalyst design and synthesis play a crucial role in refining the biodiesel production process. Particularly, catalysts derived from waste, featuring precise active sites, are recognized as important tools for achieving enhanced catalyst activity at reduced costs. Therefore, this review examines the trajectory of catalyst development for biodiesel production from various feedstocks, with a primary focus on the design of waste-derived catalytic nanostructured materials for sustainable development. It is anticipated that this review will provide insights into the next generation of sustainable biodiesel production methods.

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Source-separation of urine (urine diversion) is a well-established concept with proven sanitation benefits, promoting sustainable (waste)water management and circular economy, gaining increased attention worldwide. Although urine comprises only 1% in municipal wastewater by volume, it mostly accounts for nutrient loads in wastewater (85–90% of N, 50–80% of P, and 80–90% of K). Source-separation of urine: improves sanitation, conserves water, can partly substitute synthetic fertilizers in agriculture, and reduces energy and space requirements at wastewater treatment plants. This paper reviews the developments in source separation and valorization of urine, its benefits, methods for treatment, and challenges for implementation. Further, implications of source-separation of urine in Indian context (as an example of developing/emerging economy) is highlighted.

Graphical Abstract