Sustainable environmental practices of tea waste-a comprehensive review.

Tea, the major beverage worldwide, is one of the oldest commercial commodities traded from ancient times. Apart from many of its advantages, including health, socio-economic, climatic, and agro-ecological values, FAO has recognized that the tea value chain covering its growth in the field, processing and marketing, and finally, the hot cup at the user's hand needs to be made sustainable during all these stages. Tea generates a lot of waste in different forms in different stages of its growth and processing, and these wastes, if not managed properly, may cause environmental pollution. A planned utilization of these wastes as feedstocks for various processes can generate more income, create rural livelihood opportunities, help grow tea environmentally sustainable, avoid GHG emissions, and make a real contribution to SDGs. Thermochemical and biological conversion of tea wastes generates value-added products. This review provides an overview on the impacts of the tea wastes on the environment, tea waste valorization processes, and applications of value-added products. The application of value-added products for energy generation, wastewater treatment, soil conditioners, adsorbents, biofertilizers, food additives, dietary supplements, animal feed bioactive chemicals, dye, colourant, and phytochemicals has been reviewed. Further, the challenges in sustainable utilization of tea wastes and opportunities for commercial exploitation of value-added products from tea wastes have been reviewed.

Monitoring of land use land cover dynamics and prediction of urban growth using Land Change Modeler in Delhi and its environs, India.

In the recent decades, cities have been expanding at a great pace which changes the landscape rapidly as a result of inflow of people from rural areas and economic progression. Therefore, understanding spatiotemporal dynamics of human induced land use land cover changes has become an important issue to deal with the challenges for making sustainable cities. This study aims to determine the rate of landscape transformations along with its causes and consequences as well as predicting urban growth pattern in Delhi and its environs. Landsat satellite images of 1989, 2000, 2010 and 2020 were used to determine the changes in land use land cover using supervised maximum likelihood classification. Subsequently, Land Change Modeler (LCM) module of TerrSet software was used to generate future urban growth for the year 2030 based on 2010 and 2020 dataset. Validation was carried out by overlaying the actual and simulated 2020 maps. The change detection results showed that urban and open areas increased by 13.44% and 2.40%, respectively, with a substantial decrease in crop land (10.88%) from 1989 to 2020 and forest area increased by 3.48% in 2020 due to restoration programmes. Furthermore, the simulated output of 2030 predicted an increase of 24.30% in urban area and kappa coefficient 0.96. Thus, knowledge of the present and predicted changes will help decision-makers and planners during the process of formulating new sustainable policies, master plans and economic strategies for rapidly growing cities with urban blue-green infrastructures.

Bioengineering to Accelerate Biodiesel Production for a Sustainable Biorefinery.

Biodiesel is an alternative, carbon-neutral fuel compared to fossil-based diesel, which can reduce greenhouse gas (GHGs) emissions. Biodiesel is a product of microorganisms, crop plants, and animal-based oil and has the potential to prosper as a sustainable and renewable energy source and tackle growing energy problems. Biodiesel has a similar composition and combustion properties to fossil diesel and thus can be directly used in internal combustion engines as an energy source at the commercial level. Since biodiesel produced using edible/non-edible crops raises concerns about food vs. fuel, high production cost, monocropping crisis, and unintended environmental effects, such as land utilization patterns, it is essential to explore new approaches, feedstock and technologies to advance the production of biodiesel and maintain its sustainability. Adopting bioengineering methods to produce biodiesel from various sources such as crop plants, yeast, algae, and plant-based waste is one of the recent technologies, which could act as a promising alternative for creating genuinely sustainable, technically feasible, and cost-competitive biodiesel. Advancements in genetic engineering have enhanced lipid production in cellulosic crops and it can be used for biodiesel generation. Bioengineering intervention to produce lipids/fat/oil (TGA) and further their chemical or enzymatic transesterification to accelerate biodiesel production has a great future. Additionally, the valorization of waste and adoption of the biorefinery concept for biodiesel production would make it eco-friendly, cost-effective, energy positive, sustainable and fit for commercialization. A life cycle assessment will not only provide a better understanding of the various approaches for biodiesel production and waste valorization in the biorefinery model to identify the best technique for the production of sustainable biodiesel, but also show a path to draw a new policy for the adoption and commercialization of biodiesel.