Showing papers by "Ashok Pandey published in 2021"

A critical review on advances in the practices and perspectives for the treatment of dye industry wastewater.

Abstract: Rapid industrialization has provided comforts to mankind but has also impacted the environment harmfully. There has been severe increase in the pollution due to several industries, in particular due to dye industry, which generate huge quantities of wastewater containing hazardous chemicals. Although tremendous developments have taken place for the treatment and management of such wastewater through chemical or biological processes, there is an emerging shift in the approach, with focus shifting on resource recovery from such wastewater and also their management in sustainable manner. This review article aims to present and discuss the most advanced and state-of-art technical and scientific developments about the treatment of dye industry wastewater, which include advanced oxidation process, membrane filtration technique, microbial technologies, bio-electrochemical degradation, photocatalytic degradation, etc. Among these technologies, microbial degradation seems highly promising for resource recovery and sustainability and has been discussed in detail as a promising approach. This paper also covers the challenges and future perspectives in this field.

A critical review on various feedstocks as sustainable substrates for biosurfactants production: a way towards cleaner production.

Abstract: The quest for a chemical surfactant substitute has been fuelled by increased environmental awareness. The benefits that biosurfactants present like biodegradability, and biocompatibility over their chemical and synthetic counterparts has contributed immensely to their popularity and use in various industries such as petrochemicals, mining, metallurgy, agrochemicals, fertilizers, beverages, cosmetics, etc. With the growing demand for biosurfactants, researchers are looking for low-cost waste materials to use them as substrates, which will lower the manufacturing costs while providing waste management services as an add-on benefit. The use of low-cost substrates will significantly reduce the cost of producing biosurfactants. This paper discusses the use of various feedstocks in the production of biosurfactants, which not only reduces the cost of waste treatment but also provides an opportunity to profit from the sale of the biosurfactant. Furthermore, it includes state-of-the-art information about employing municipal solid waste as a sustainable feedstock for biosurfactant production, which has not been simultaneously covered in many published literatures on biosurfactant production from different feedstocks. It also addresses the myriad of other issues associated with the processing of biosurfactants, as well as the methods used to address these issues and perspectives, which will move society towards cleaner production.

Techno-economics and life-cycle assessment of biological and thermochemical treatment of bio-waste

Abstract: The energy sector contributed to three-fourth of overall global emissions in the past decade. Biological wastes can be converted to useful energy and other byproducts via biological or thermo-chemical routes. However, issues such as techno-economic feasibility and lack of understanding on the overall lifecycle of a product have hindered commercialization. It is needed to recognize these inter-disciplinary factors. This review attempts to critically evaluate the role of technology, economics and lifecycle assessment of bio-waste in two processing types. This includes: 1. biological and, 2. thermo-chemical route. The key findings of this work are: 1. Policy support is essential for commercialization of a waste treatment technology; 2. adequate emphasis is necessary on the social dimensions in creating awareness; and 3. from a product development perspective, research should focus on industrial needs. The choice of the treatment and their commercialization depends on the regional demand of a product, policy support, and technology maturity. Utilization of bio-wastes to produce value-added products will enhance circular economy, which in turn improves sustainability.

A critical review on the development stage of biorefinery systems towards the management of apple processing-derived waste

Abstract: Apple is among the most consumed fruits in the world and the expansion of their processing is increasing the generation of waste such as apple pomace. It finds some applications in food and feed systems, anaerobic digestion, and composting; however it most ends in landfills or in informal disposal. Therefore, waste management strategies that address this waste accumulation need to be explored. This review provides a state-of-art of valorization strategies adopted for recovery of value added products from apple processing-derived waste and discusses on their development stage. The research community has laid most of its efforts on incorporation of apple pomace into feed and food systems and in the development of pectin- and phenolics-extraction methods. Incorporation of apple pomace in feed and food systems is still negligible due to its low protein and high fiber contents. Therefore, coupling apple pomace with microbial conversion for nutritional upgrade could change this scenario. Some environmentally-friendly techniques have been developed for extraction of pectin and phenolics, but major developments are needed on their integration to attain tailored extraction of several compounds. Recovery of value added routes of apple pomace towards production of bio-chemicals are characterized by lack of deep research studies and of a holistic approach. Integrated approach with techno-economic analysis, life-cycle assessment, and inter-sectorial initiatives will possibly reveal the most promising valorization routes.

Bioremediated techniques for remediation of metal pollutants using metagenomics approaches: A review

Abstract: Microbe-induced remediation of toxic metals has attained more research interests by implementing the bioremediation process for sustainable development. Heavy metals are known to be naturally occurring elements, but they are released in vast quantities into different environmental sources due to anthropogenic activity. Metals are persisting and non-biodegradable, which can enter the food chain via crop plants, and might accumulate in the animal body through biomagnification. At the molecular level, microbial treatment of metals provides an excellent and new perspective for the prevention of environmental pollution. Novel bioremediation organisms provide excellent and new perspectives through their specific biodegradation mechanisms at the molecular level. All DNA found within the metagenomic analysis of a populated environment includes several screening approaches that might be used to simplify the processing and examination of specific genomic information in bioremediation experiments. Development in next-generation sequencing (NGS) demands detailed metagenomic analysis of environmental microbes offering unparalleled perspectives through key biosorption mechanisms. The present review explored how the metagenomic approaches could help in analyzing the functional and structural characteristics of microbial communities in response to metal detoxification.

Kinetic and thermodynamic investigations of sewage sludge biochar in removal of Remazol Brilliant Blue R dye from aqueous solution and evaluation of residual dyes cytotoxicity

Abstract: Biochar derived from sewage sludge has emerged as an alternative for sustainable utilization as a soil amendment. However, the use of sewage sludge biochar (SSB) has been less explored in the field of wastewater treatment. Therefore, the purpose of this study was to investigate the efficiency of biochar prepared from sewage sludge at 450 °C (SSB-450), as an adsorbent for the removal of Remazol Brilliant Blue R (RBBR) from an aqueous solution. Brunauer–Emmett–Teller (BET), Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) spectroscopy were used to characterize SSB-450, with maximum RBBR removal efficiency. The removal of RBBR from aqueous solution by SSB-450 was investigated in batch mode at varying adsorbent dose, contact time, initial RBBR dye concentration temperature and pH. The BET analysis showed the type IV isotherm that indicates the mesoporous structure of SSB-450. The total pore volume and BET specific surface area of SSB-450 particles were found to be 3.936 cm −3/g and 12.447 m2/g, respectively. The RBBR dye adsorption ( q e ) at equilibrium by SSB-450 was found to increase from 8.56 to 80.6 mg g−1 with an increase in initial dye concentration from 10 to 100 mg L−1. The maximum monolayer adsorption capacity (qmax) was 126.59 mg/g of SSB-450, determined by the Langmuir adsorption model. At various RBBR dye concentrations (10 to 100 mg/g), the range of the separation factor ( R L ) was 0.98–0.9, which indicates the favourable adsorption of RBBR dye onto the surface of SSB-450. Besides, Evans blue and triphenyl tetrazolium chloride (TTC) staining of Allium cepa L. roots germinated with dye solutions revealed that biochar treated residual RBBR was non-cytotoxic.

Sustainable green processing of grape pomace for the production of value-added products: An overview

Abstract: In recent years, the recovery of valuable compounds from food waste like grape pomace is an emerging issue in the food sector. Grape pomace or marc can be considered as an important solid waste that is produced from the wine industries after the pressing and fermentation process. The waste produced from the wine industry causes pollution, difficulties in disposal/management, and also economic loss. Grape pomace consists of approximately 10%–30% of the crushed grape mass and other value-added products like unfermented sugars, polyphenols, pigments, alcohol, and tannins, etc. The recovery of these compounds by the most suitable and eco-friendly manner extraction techniques and able to maximize yield without compromising the stability/quality of the product is a challenging task. Grape pomace has greater potential values, there are technologies still to be developed and adopted in the winery and other associated industries. Since grape pomace is a natural plant product, it is rich in lignocellulosic compounds and could be used as a promising feedstock for the production of renewable energy. This review gives a brief overview of the extraction techniques like, Solid–Liquid Extraction, Supercritical Fluid Extraction, Accelerated Solvent Extraction, Microwave-Assisted Extraction, Enzyme Assisted Extraction, etc. Besides, the extraction of value-added products from the grape pomace and the biochemical and thermo-chemical management for recovery of energy, production of alcohol, fuel, and beverage, other novel products, and various applications such as environmental remediation and bio-surfactants are described briefly.

Technological perspectives for utilisation of waste glycerol for the production of biofuels: A review

Abstract: The depletion of fossil fuel reserves and the ever-increasing demand for energy due to growing industries, rapid population growth, and increasing concerns about environmental pollution have led to the exploration of green and alternative fuels. Bioethanol is one of the most promising biofuels and a key factor in shifting the transportation sector’s dependence from petroleum-based sources to renewable and sustainable energy sources. This review highlights the development of bioethanol from first to third-generation. First-generation sources include food crops, second-generation sources include feedstocks from agricultural residues, municipal waste or forestry waste, and third-generation sources include algal biomass to produce bioethanol for commercial scale in world are emphasised. Various methods such as pre-treatment, hydrolysis by acid and enzymes, fermentation to produce bioethanol, and distillation a separation processes to obtain anhydrous ethanol are described. Current advances in using biodiesel industrial by-product crude glycerol waste as the best alternative, renewable and sustainable source for ethanol production in the circular economy are also presented. The significant role of crude glycerol in various applications and the conversion of glycerol to ethanol are focused. In addition, the challenges and opportunities for future work are highlighted. The potential application of bioethanol as a biofuel to reduce environmental impact for a clean and sustainable future is described.

Resource recovery through bioremediation of wastewaters and waste carbon by microalgae: a circular bioeconomy approach.

Abstract: Microalgal biomass-based biofuels are a promising alternative to fossil fuels. Microalgal biofuels' major obstacles are the water and carbon sources for their cultivation and biomass harvest from the liquid medium. To date, an economically viable process is not available for algal based biofuels. The circular bioeconomy is an attractive concept for reuse, reduce, and recycle resources. The recovery of nutrients from waste and effluents by microalgae could significantly impact the escalating demands of energy and nutraceutical source to the growing population. Wastewaters from different sources are enriched with nutrients and carbon, and these resources can be recovered and utilized for the circular bioeconomy approach. However, the utilization of wastewaters and waste seems to be an essential strategy for mass cultivation of microalgae to minimizing freshwater consumption, carbon, nutrients cost, nitrogen, phosphorus removal, and other pollutants loads from wastewater and generating sustainable biomass for value addition for either biofuels or other chemicals. Hence, the amalgamation of wastewater treatment with the mass cultivation of microalgae improved the conventional treatment process and environmental impacts. This review provides complete information on the latest progress and developments of microalgae as potential biocatalyst for the remediation of wastewaters and waste carbon to recover resources through biomass with metabolites for various industrial applications and large-scale cultivation in wastewaters, and future perspectives are discussed.

Glycerol waste to value added products and its potential applications

Abstract: The rapid industrial and economic development runs on fossil fuel and other energy sources. Limited oil reserves, environmental issues, and high transportation costs lead towards carbon unbiased renewable and sustainable fuel. Compared to other carbon-based fuels, biodiesel is attracted worldwide as a biofuel for the reduction of global dependence on fossil fuels and the greenhouse effect. During biodiesel production, approximately 10% of glycerol is formed in the transesterification process in a biodiesel plant. The ditching of crude glycerol is important as it contains salt, free fatty acids, and methanol that cause contamination of soil and creates environmental challenges for researchers. However, the excessive cost of crude glycerol refining and market capacity encourage the biodiesel industries for developing a new idea for utilising and produced extra sources of income and treat biodiesel waste. This review focuses on the significance of crude glycerol in the value-added utilisation and conversion to bioethanol by a fermentation process and describes the opportunities of glycerol in various applications.

Bioengineered Biochar As Smart Candidate For Resource Recovery Toward Circular Bio-Economy: A Review.

Abstract: Biochar's ability to mediate and facilitate microbial contamination degradation, as well as its carbon-sequestration potential, has sparked interest in recent years. The scope, possible advantages (economic and environmental), and future views are all evaluated in this review. We go over the many designed processes that are taking place and show why it is critical to look into biochar production for resource recovery and the role of bioengineered biochar in waste recycling. We concentrate on current breakthroughs in the fields of engineered biochar application techniques to systematically and sustainable technology. As a result, this paper describes the use of biomass for biochar production using various methods, as well as its use as an effective inclusion material to increase performance. The impact of biochar amendments on microbial colonisation, direct interspecies electron transfer, organic load minimization, and buffering maintenance is explored in detail. The majority of organic and inorganic (heavy metals) contaminants in the environment today are caused by human activities, such as mining and the use of chemical fertilizers and pesticides, which can be treated sustainably by using engineered biochar to promote the establishment of a sustainable engineered process by inducing the circular bioeconomy.