Anwesha Borthakur

Emerging trends in photodegradation of petrochemical wastes: a review

Various human activities like mining and extraction of mineral oils have been used for the modernization of society and well-beings. However, the by-products such as petrochemical wastes generated from such industries are carcinogenic and toxic, which had increased environmental pollution and risks to human health several folds. Various methods such as physical, chemical and biological methods have been used to degrade these pollutants from wastewater. Advance oxidation processes (AOPs) are evolving techniques for efficient sequestration of chemically stable and less biodegradable organic pollutants. In the present review, photocatalytic degradation of petrochemical wastes containing monoaromatic and poly-aromatic hydrocarbons has been studied using various heterogeneous photocatalysts (such as TiO2, ZnO and CdS. The present article seeks to offer a scientific and technical overview of the current trend in the use of the photocatalyst for remediation and degradation of petrochemical waste depending upon the recent advances in photodegradation of petrochemical research using bibliometric analysis. We further outlined the effect of various heterogeneous catalysts and their ecotoxicity, various degradation pathways of petrochemical wastes, the key regulatory parameters and the reactors used. A critical analysis of the available literature revealed that TiO2 is widely reported in the degradation processes along with other semiconductors/nanomaterials in visible and UV light irradiation. Further, various degradation studies have been carried out at laboratory scale in the presence of UV light. However, further elaborative research is needed for successful application of the laboratory scale techniques to pilot-scale operation and to develop environmental friendly catalysts which support the sustainable treatment technology with the “zero concept” of industrial wastewater. Nevertheless, there is a need to develop more effective methods which consume less energy and are more efficient in pilot scale for the demineralization of pollutant.

Generation and Management of Electronic Waste in the City of Pune, India

Electronic waste (E-waste) illustrates discarded appliances that utilize electricity for their functioning. It is one of the fastest growing waste streams across the globe. A study on the generation and management of E-waste was conducted in the city of Pune, India, involving four different stakeholders, namely, the information technology (IT) sector, banking sector, educational institutes, and households. All these stakeholders are listed by the Indian Ministry of Environment and Forest as major contributors to the problem of E-waste in the country. Semistructured interviews were carried out at 4 IT companies, 10 banks, 16 educational institutes, and 50 households. Results show that the generation of E-waste with respect to computer waste is highest at the IT sector, followed by the banking sector. Apart from a few exceptions, rudimentary management practices were prevalent among the stakeholders. There is a lack of awareness on concerns related to E-waste. Establishing sustainable E-waste management practices, formulation and implementation of appropriate policy initiatives, transparency in the system, and educating people on their responsibility toward global E-waste problem are essential in order to address the emerging concern of E-waste in India.

Generation and Management of Electronic Waste in India

Electronic waste (E-waste) or waste electrical and electronic equipment (WEEE) refers to obsolete and discarded appliances that operates on electricity. Due to our constantly evolving dependence on electrical and electronic equipments (EEEs) in every walk of lives, the amount of E-waste generated worldwide is thriving at an alarming rate, while the management practices and policy-level initiatives are still at an embryonic stage, especially in most of the developing countries. With respect to countries like India, the current methods of storage, processing, recycling, and disposal of E-waste have immense potential to harm human health and environment. This article is an attempt to evaluate the involvement of various stakeholders in the generation and management of E-waste in India by identifying and assessing them. The dominance of informal E-waste recycling sector along with its all socio-economic, health, and environmental implications is addressed. Current status of formal recycling units in the country is assessed upon. A case study assessing various stakeholders’ involvement is incorporated. The findings and conclusions of the article call for an integrated approach in Indian E-waste management scenario including significant considerations such as the identification of diverse range of stakeholders in the E-waste generation and management processes. A sustainable E-waste management system in the country is only possible by identification of the functionalities of various stakeholders.

Current and emerging trends in bioremediation of petrochemical waste: A review

ABSTRACT Various industries release harmful petrochemical contaminants into the environment. To treat these petrochemical contaminants at source, different physical, chemical, and biological methods have been proposed and applied worldwide. However, physical and chemical methods have their own advantages and limitations; in this review, we majorly focused on the biodegradation of petrochemical wastes. First, a background study on the literature available in this field is presented. Second is a review of the toxic effects of petrochemical waste and various physical and chemical processes, followed by elaborate biological processes available for petrochemical waste degradation. Further, different aspects of bioremediation, such as modes, factors, limitations, and future perspectives are critically reviewed and presented. It was found that most of the studies performed on bioremediation of petrochemical waste employed bacteria for the degradation purpose. Some studies also made use of algae, fungi, yeast, genetically modified organisms, biosurfactants, or a consortium of these microbes. Moreover, use of bioremediation is still limited at field scale due to certain limitations, which have been elaborated in this article. Overall, we strongly believe that with bioremediation capturing the attention of environmentalists worldwide, there is still a prevailing need to scale up from lab to land level applications and adaptations.

Exploring temple floral refuse for biochar production as a closed loop perspective for environmental management

Religious faith and ritual activities lead to significant floral offerings production and its disposal as waste to the nearby open lands and water bodies. These activities result into various social and environmental nuisances because of their high organic content. Alternatively, it can be used as valuable resources for various biochemical and thermo-chemical processes. Floral refuse has been utilized in natural dye extraction, however, the residual solid refuse is of significant environmental concern due to its nutrient rich nature. This study explores the potential utilization of solid residue of temple floral refuse after natural dye extraction by thermo-chemical decomposition of it. The slow pyrolysis of solid residue was performed at 350 °C and 500 °C, and the biochar yield of 42 and 36% was obtained, respectively. TGA-DTG analysis was performed to observe the thermo-chemical behaviour of floral refuse. The biochar products were further characterized by FTIR, SEM, EDX, BET, XRD, and RAMAN spectroscopy to observe the impact of pyrolysis temperature (PT) on the resulting material, i.e. biochar and its possible application measures. EDX results revealed the presence of various macro-nutrients such as C, N, P, K Ca and Mg in different proportions which showed its soil amelioration potential. Moreover, based on the SEM and BET results, biochar prepared at 500 °C was further explored for adsorption of methylene blue dye at various dose and pH conditions. Based on Langmuir (R2 = 0.98) and Freundlich (R2 = 0.97) isotherms, it is found as a potential adsorbent material for removal of methylene blue dye. The results revealed that biochar conversion of colour extracted floral refuse can be a vital option for quick and efficient management of it in a closed loop approach.

Electronic Waste in Urban India: A Major Sustainability Challenge

Environment- and resource-friendly management of electronic waste is a serious concern in contemporary urban India. The already existent solid waste management problem in India has been aggravated manifolds with the advent of domestically generated and illegal imported E-waste. This chapter evaluates the current E-waste scenario in urban India. Existing E-waste management challenges in urban India have been assessed taking into account the current E-waste disposal practices/preferences, dominance of the informal recycling sector, stakeholders’ awareness, etc. Our experience calls for stringent policy instruments and management strategies in order to address this crisis from its roots.

Computer and mobile phone waste in urban India: an analysis from the perspectives of public perception, consumption and disposal behaviour

Sustainable management of Electronic waste (E-waste) is a major challenge for contemporary India, an emerging economy burdened with both the domestic generation and illegal import of E-waste. Considering the ever-increasing complexities of E-waste in Indian cities, this paper aims to evaluate the current trends, opportunities and challenges associated with consumption of electronic items (with respect to computers and mobile phones) and disposal of E-waste in urban India. Bangalore, a city popularly known as the ‘Silicon Valley of India’, is considered as a case study in order to evaluate public awareness, household consumption and E-waste disposal behaviours. The city profile of Bangalore indicates that it has a rapidly emerging market for electronics and thus, has the potential to act as a ‘model’ for evaluating the issues concerning E-waste in metropolitan India. Questionnaires were distributed originally among 300 households with an effective response rate of 63.3%. The results indicate that the majority of households (59.3%) still retain their obsolete electronics due to lack of knowledge about proper E-waste management. High awareness about E-waste and high willingness to recycle/repair their E-waste (above 80% in both cases) are yet to be translated into responsible disposal/recycling behaviour as 95.8% of households have no knowledge about the presence of any formal recycling centre. Income, education, age and gender dimensions associated with E-waste disposal behaviour and awareness were also evaluated. Although we found no gender differences for most of the parameters, there have been some interesting correlations in age and income-wise segregation of disposal behaviour. We noted that the city of Bangalore still possesses some typical Indian socio-cultural characteristics, such as considering E-waste as ‘valuables’, changing several hands before final disposal, defying ‘brand’ or ‘looks’ consciousness, etc., which could be directed towards responsible E-waste disposal behaviours. We suggest that establishing appropriate and convenient E-waste collection/recycling facilities, ensuring responsible household disposal behaviour, implementing effective laws and legislation, and organizing mass E-waste awareness campaigns would aid in addressing the current E-waste concerns in the city.