Current Happenings ENVS News

Dr Pankaj Pathak from the Department of Environmental Science has been keenly involved in research studies involving solid waste management and the effective conversion of wastes to energy. Her latest research publication Sustainable approach for valorization of solid wastes as a secondary resource through urban mining proposes an enhanced solution for the sustainable management of different types of solid wastes. It was published in the Journal of Environmental Management with an impact factor 8.98.

In this paper, sustainable alternative valorisation techniques that aid in maximum recovery from waste materials, and associated challenges and limitations have been highlighted. These solid wastes mainly include construction and demolition wastes, organic food wastes, plastic, and WEEE (Waste electrical and electronic equipment) from various sources. In order to overcome these challenges, a sustainable circular model is recommended in this paper that will help minimise the negative environmental impacts, maximise the life cycle of material, reduce the consumption of fossil fuels, and thereby sustainably manage waste. Implementation of this recommendation can help in achieving the target of sustainable development goals (SDGs).

The article was published in collaboration with her PhD Scholar MSSR Tejaswini, and D.K. Gupta, Member Secretary in the Hazardous Substance Management Division in the Ministry of Environment, Forest and Climate Change, New Delhi.

Abstract

The incessant population has increased the production and consumption of plastics, paper, metals, and organic materials, which are discarded as solid waste after their end of life. The accumulation of these wastes has created growing concerns all over the world. However, conventional methods of solid waste management i.e., direct combustion and landfilling have caused several negative impacts on the environment (releasing toxic chemicals and greenhouse gases, huge land use) besides affecting human health. Therefore, it is requisite to determine sustainable alternative technologies that not only help in mitigating environmental issues but also increase the economic value of the discarded solid wastes. This process is known as urban mining where waste is converted into secondary resources and thereby conserves the natural primary resources. Thus, this review highlights the technological advancements in the valorisation process of discarded wastes and their sustainable utilization. We also discussed several limitations of the existing urban mining processes and further the feasibility of valorisation techniques was critically analysed from a techno-economical perspective. This paper recommends a novel sustainable model based on the circular economy concept, where waste is urban mined and recovered as a secondary resource to support the united nations sustainable development goals (SDGs). The implementation of this model will ultimately help the developing countries to achieve the target of SDGs 11, 12, and 14.

Continue reading →

Rampant exploitation of resources has indisputably contributed to an enormous rise in solid waste generation. It has been estimated that solid waste generation will shoot up from 1.3 billion tons to 2.2 billion tons in 2025. While 16% of the high-income countries’ population corresponds to 34% of waste being generated, only 5% of the waste generated is attributed to the low-income countries. However, it is a meagre volume of 39% that is collected leaving the rest to rot. This open dumping affects the environment and creates pollution. In addition, improper waste disposal techniques have resulted in emissions of 1.6 billion tons of CO2eq in 2016. Effective waste management is thus a matter of concern in third-world countries.

Assistant Professor Dr Karthik Rajendran and his post-doctoral scholar Dr V S Vigneswaran from the Department of Environmental Science in collaboration with Dr Mukesh Kumar Awasthi from the College of Natural Resources and Environment, Northwest A&F University, PR China, have published their research papers on solid waste management in the journal Bioresource Technology having an Impact Factor of 11.8. This is the second-best journal in the Environmental Engineering category according to SCImago Journal Rank (SJR). The journal aims to disseminate knowledge in the areas of biomass, biological waste treatment, bioresource systems analysis, and technologies associated with conversion or production.

The paper titled “Recovery of value-added products from biowaste: A review” introduces microbial biotechnology for the valorisation of solid wastes. Microbial biotechnology offers several solutions for the utilisation of waste resources. The carbon present in solid and gaseous wastes can be utilised by the microbes as carbon feedstock for their growth. During the growth of microbes on wastes, it produces primary and secondary metabolites, which are of significant use to humankind. The microbes can also be engineered biotechnologically to use waste resources and produce new compounds. Microbial biotechnology, with the use of various genetic engineering tools, can be efficiently explored for the microbes’ modification to utilise different wastes thereby making the environment clean by reducing GHG emissions.

Abstract of the Research

This review provides an update on the state-of-the art technologies for the valorization of solid wastes and its mechanism to generate various bio-products. The organic content of these wastes can be easily utilized by the microbes and produce value-added compounds. Microbial fermentation techniques can be utilized for developing waste biorefinery processes. The utilization of lignocellulosic and plastic wastes for the generation of carbon sources for microbial utilization after pre-processing steps will make the process a multi-product biorefinery. The C1 and C2 gases generated from different industries could also be utilized by various microbes, and this will help to control global warming. The review seeks to expand expertise about the potential application through several perspectives, factors influencing remediation, issues, and prospects.

Read the full article here

Food waste in solid forms has been generated throughout the entire food life cycle, from the agricultural production process to the distribution of processed foods and even to their consumption in the market. Considering that approximately 1.3 billion tons of edible food waste is leftover annually, recycling it in the biorefinery will contribute both economically and socially. Another of their publication “Myco-biorefinery approaches for food waste valorization: Present status and future prospects” discusses various types of food waste sources and their evaluation targets. Food waste can be evaluated in fungi-based bioproduction processes for this purpose. In addition, potential biorefinery systems, circular bioeconomy processes, techno-economic studies, and social/ethical aspects of food wastes in the evaluation of valuable products are discussed.

Abstract of the Research

The increase in population and urbanization leads to the generation of a large amount of food waste (FW) and its effective waste management is a major concern. Its putrescible nature and high moisture content are the major limiting factors for cost-effective FW valorization. Bioconversion of FW for the production of value-added products is an eco-friendly and economically viable strategy for addressing these issues. Targeting the production of multiple products will solve these issues to a greater extent. The article provides an overview of the bioconversion of FW to different value-added products.

Read the full article here