ORIGINAL RESEARCH PAPER
Environmental Engineering
A. Nuryadin; T. Imai
Abstract
BACKGROUND AND OBJECTIVES: Fixed-bed column has been considered an industrially feasible technique for phosphate removal from water. Besides the adsorption capacity, the effectiveness of an adsorbent is also determined by its reusability efficiency. In this study, phosphate removal by a synthesized amorphous ...
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BACKGROUND AND OBJECTIVES: Fixed-bed column has been considered an industrially feasible technique for phosphate removal from water. Besides the adsorption capacity, the effectiveness of an adsorbent is also determined by its reusability efficiency. In this study, phosphate removal by a synthesized amorphous zirconium (hydr)oxide/MgFe layered double hydroxides composite in a fixed-bed column system was examined. METHODS: The effects of flow rate, bed height, phosphate concentration, solution pH, and adsorbent particle size on the phosphate adsorption ability were examined through a series of continuous adsorption experiments. The appropriate breakthrough curve models, phosphate adsorption from real anaerobic sludge and synthetic seawater, column regeneration and reusability, and adsorption mechanism were also investigated for practical application feasibility. FINDINGS: The results showed that the increased bed height and phosphate concentration, and reduced flow rate, pH, and adsorbent particle size were found to increase the column adsorption capacity. The optimum adsorption capacity of 25.15 mg-P/g was obtained at pH 4. The coexistence of seawater ions had a positive effect on the phosphate adsorption capacity of the composite. Nearly complete phosphate desorption, with a desorption efficiency of 91.7%, could be effectively achieved by 0.1 N NaOH for an hour. Moreover, the initial adsorption capacity was maintained at approximately 83% even after eight adsorption-desorption cycles, indicating that the composite is economically feasible. The high phosphate adsorption capacity of the composite involves three main adsorption mechanisms, which are electrostatic attraction, inner-sphere complexation, and anion exchange, where the amorphous zirconium hydr(oxide) on the surface of the layered double hydroxides likely increased the number of active binding sites and surface area for adsorption. CONCLUSION: The amorphous zirconium (hydr)oxide/MgFe layered double hydroxides composite, with its high adsorption capacity and superior reusability, has the potential to be utilized as an adsorbent for phosphorus removal in practical wastewater treatment. This study provides insights into the design of amorphous zirconium (hydr)oxide/MgFe layered double hydroxides composite for phosphorus removal and recovery in a practical system. ==========================================================================================COPYRIGHTS©2021 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.==========================================================================================
ORIGINAL RESEARCH PAPER
Environmental Engineering
J. O. Castillo-Miranda; F. J. Rodríguez-Gómez; J. Genescá-Llongueras; L. G. Ruiz-Suárez; J. A. García-Reynoso
Abstract
BACKGROUND AND OBJECTIVES: Atmospheric zinc corrosion in the Mexico City Metropolitan area has long been attributed mainly to the effect of pollutants such as sulfur dipxide. There are changes in the urban atmosphere's chemical composition due to the implementation of air quality policies focused on ...
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BACKGROUND AND OBJECTIVES: Atmospheric zinc corrosion in the Mexico City Metropolitan area has long been attributed mainly to the effect of pollutants such as sulfur dipxide. There are changes in the urban atmosphere's chemical composition due to the implementation of air quality policies focused on reducing the emission of sulfur dipxide and other pollutants. This study's objectives were to estimate and map the contribution of nitric acid on zinc's atmospheric corrosion process METHODS: The impact of nitric acid on zinc is feasible to estimate using a function for a multi-pollutant situation. This function contemplates the sum of two contributions: one of nitric acid and another that includes sulfuric acid and climatic parameters. The multi-pollutant function is suitable to apply in areas without the strong influence of chlorides and tropical and subtropical climates, comparable to the Mexico City Metropolitan area. FINDINGS: The results showed that spatial and temporal estimation of corrosion rates in grams per square meter of zinc was made for 2015-2019, using data modeling in a geographic information system. The maps of corrosion rates allowed us to visualize that, in general, the "southwest" zone has the most significant effects and that the lowest corrosion rates were presented in 2019 as an outcome of the implementation of air quality programs. Furthermore, a contribution of nitric acid up to 32% to the zinc corrosion rate was estimated. CONCLUSION: The construction of corrosion rate maps provides a spatial and temporal estimate that allows visualizing areas where zinc materials are at risk corrosion due to the dispersion of atmospheric pollutants and climatic parameters. Likewise, it can represent a decision-making tool for the implementation of atmospheric corrosion studies of materials. ==========================================================================================COPYRIGHTS©2021 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.==========================================================================================
ORIGINAL RESEARCH PAPER
Environmental Management
M. Pinskaya; O. Meleshchenko; O. Kovalchuk; O. Karpenko; E. Kompanets
Abstract
BACKGROUND AND OBJECTIVES: The requirements of stakeholders for the qualitative transformation of the approaches of industrial enterprises – environmental users to introduction of economic activities cause an increase in the role of environmental responsibility as their strategic priority for development. ...
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BACKGROUND AND OBJECTIVES: The requirements of stakeholders for the qualitative transformation of the approaches of industrial enterprises – environmental users to introduction of economic activities cause an increase in the role of environmental responsibility as their strategic priority for development. The purpose of the study is to improve the practical tools for calculating and developing strategies for the development of environmental responsibility of industrial enterprises. METHODS: In the study, tools for assessing the level of environmental initiative of an industrial enterprise as an integrated indicator of environmental initiative are suggested. It is expressed as the arithmetic mean of ten factors of environmentally proactive behavior of industrial enterprises. To achieve the objectives of the study, methods of criterion-qualitative assessment are suggested, such as expert assessment and survey. The assessment system includes ten factors rated on a 10-point scale and weighted by significance. The integrated indicator of the environmental initiative acquires values within, is a stimulant of environmental responsibility. FINDING: One justified a scientific and methodological approach to assessing the level of environmental responsibility or the industrial enterprise, including calculation of the corresponding taxonomic indicator with consideration of the quantitative factors of its environmental responsibility and the qualitative and quantitative factors of environmental initiative. This enables the possibility to assess the relevant state of environmental responsibility and determine the volumes for further correction of the ecological strategy for the development of the industrial enterprise. CONCLUSION: As a conclusion, practical recommendations are made for the implementation of organizational and economic support of environmental responsibility in the development strategy of an industrial enterprise taking into account the impact of its environmental initiative and environmental duty. The level of environmental responsibility of industrial enterprises taken into account when developing recommendations on adjustment of their environmental strategy of development is determined, which as a whole allowed to form organizational and economic support for environmental responsibility of the enterprises under study. Thus, an enterprise, which only ensures compliance with environmental emission standards (compensation strategy or sufficiency strategy) cannot be characterized by a high level of environmental responsibility. To ensure a high level of environmental responsibility, an industrial enterprise must rely on a proactive strategy or a strategy for sustainable use of nature. ==========================================================================================COPYRIGHTS©2021 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.==========================================================================================
ORIGINAL RESEARCH PAPER
Environmental Engineering
M. Ikhwan; R. Wafdan; Y. Haditiar; M. Ramli; Z. A. Muchlisin; S. Rizal
Abstract
BACKGROUND AND OBJECTIVES: El Niño - Southern Oscillation is known to affect the marine and terrestrial environment in Southeast Asia, Australia, northern South America, and southern Africa. There has been much research showing that the effects of El Niño - Southern Oscillation are extensive. ...
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BACKGROUND AND OBJECTIVES: El Niño - Southern Oscillation is known to affect the marine and terrestrial environment in Southeast Asia, Australia, northern South America, and southern Africa. There has been much research showing that the effects of El Niño - Southern Oscillation are extensive. In this study, a simulation of an El Niño event is carried out, which is ideal in the vertical layer of the Pacific Ocean (0-250 meters). The fast Fourier transform is used to process the vertical modeling data so that the results can accurately represent El Niño. METHODS: A non-hydrostatic 3-dimensional numerical model is used in this research. To separate the signal produced and obtain the quantitative difference of each sea layer, the simulation results are analyzed using the fast Fourier transform. Winds blow from the west to the east of the area in perfect El Niño weather, with a reasonably high wind zone near the equator (forming a cosine). Open fields can be found on the north and south sides, while closed fields can be found on the west and east sides. Density is uniform up to a depth of 100 meters, then uniformly increases by 1 kilogram per cubic meter from 100 to 250 meters. FINDINGS: The results of the model simulation show that one month later (on the 37th day), the current from the west has approached the domain's east side, forming a complete coastal Kelvin wave. The shape of coastal Kelvin waves in the eastern area follows a trend that is similar to the OSCAR Sea Surface Velocity plot data obtained from ERDDAP in the Pacific Ocean in October 2015. In this period, the density at a depth of 0-100 meters is the same, while the density at the depth layer underneath is different. CONCLUSION: Strong winds could mix water masses up to a depth of 100 meters, implying that during an ideal El Niño, the stratification of the water column is influenced by strong winds. The eastern domain has the highest sea level amplitude, resulting in perfect mixing up to a depth of 100 m, while wind effect is negligible in the lower layers. The first layer (0-50 m) and the second layer (50-100 m) have the same density and occur along the equator, according to FFT. The density is different and much greater in the third layer (100-150 m). ==========================================================================================COPYRIGHTS©2021 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.==========================================================================================
REVIEW PAPER
Environmental Management
G. Saini; P. S. Deepak
Abstract
The entire world is reeling under the worst pandemic of last 100 years. Over 128 million people have been infected with it and 2.8 million deaths have already taken place, till 30th March 2021. The identification of materials positive cases is the first step towards its containment and treatment. However, ...
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The entire world is reeling under the worst pandemic of last 100 years. Over 128 million people have been infected with it and 2.8 million deaths have already taken place, till 30th March 2021. The identification of materials positive cases is the first step towards its containment and treatment. However, testing of individuals is an extensive, expensive and time-consuming exercise. In addition, societal taboos are also associated with infected individuals resulting in very few people volunteering for testing, esp. in the developing and under-developed world. An alternative approach that circumvents individual testing is the wastewater-based epidemiology. A state-of-the-art review of this method is provided in context of its utility for COVID-19 detection. This technique relies on collecting and testing samples from sewers and/or wastewater treatment plants for the presence of pathogens and then using that data to determine and predict the spread of the infection, thereby allowing the provision of appropriate containment and treatment steps. The study covers key aspects of wastewater-based epidemiology application for COVID-19 detection including its need, detailed process of detection and assessment, data analysis, economics and challenges to its application. Findings from a number of case studies are presented to elucidate the utility of this technique. It is clearly seen that WBE-based approach is a much better strategy as compared to individual testing and can be adopted to prevent further spread of Covid-19. The work is expected to further emphasize the application of this method for COVID (and other pandemic) detection and implementing containment strategies. This is clearly a much more economical and non-intrusive approach as compared to the individual testing. ==========================================================================================COPYRIGHTS©2021 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.==========================================================================================
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