Advances in Wastewater and Solid Waste Treatment Processes

A special issue of Processes (ISSN 2227-9717). This special issue belongs to the section "Environmental and Green Processes".

Deadline for manuscript submissions: 31 May 2025 | Viewed by 5425

Special Issue Editors


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Guest Editor
Department of Environmental Ecology and Landscape Management, Faculty of Natural Sciences, Comenius University, Ilkovičova 6, Mlynská dolina B2, 842 15 Bratislava, Slovakia
Interests: environmental qality (water, soil, and biota) monitoring; water and solid waste treatment by physico-chemical and biological method (bioremediation techniques); environmental policy; natural zeolites
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Guest Editor
School of Applied Sciences, University of Wolverhampton, Wolverhampton WV1 1LY, UK
Interests: zeolites; microporous and mesoporous materials; pollution remediation

Special Issue Information

Dear Colleagues,

Mankind is currently facing urgent challenges in meeting rising demands for clean water as the available supplies of freshwater are decreasing due to population growth and extended water pollution. This also includes inadequate water treatment infrastructure due to global climate change and increasing consumption of ultrahigh-quality water from various modern and sophisticated industrial branches. The protection of water treatment systems against potential chemical and biological contamination, in the time of increasing diversity, is also becoming a critical issue in water resources planning. Environmental requirements are becoming of great importance in today´s society, since there is an increased interest in the industrial use of renewable resources. Biomimetics and bioinspiration is one of the most progressive, recently developed sciences, which deals with nature and living systems in order to provide sustainable life for future generations. With a more complex insight into living  organisms and an understanding of their functions, the ability to mimic nature has increased dramatically over several decades and, thus, nature-driven solutions have  brought technological progress to a higher level. Nevertheless, the above-mentioned discipline offers then a substantial scientific portfolio for the development of current material chemistry, specifically for novel nanoscale adsorbent synthesis. It is supposed that basic constructional processes of matter like biomineralisation, biomimetics, supramolecular preorganisation or interfacial molecular recognition (templating), and other recent techniques and new advanced nanomaterials contribute to a certain portfolio for potential Green Synthesis or Processing of the future. Moreover, there is a gradual insistence that clean industrial production, water reuse and solid waste recycling can provide sustainable living for the next generations.

Municipal solid waste (MSW) management can be defined as the discipline associated with the generation, storage, collection, transfer, processing, and disposal of MSW, in a way which is governed by the best principles of public health, economics, engineering, aesthetics, and other environmental considerations. Waste utilization management is explored in the context of the dominant principle of the circular economy: waste should be processed into secondary resources, reducing environmental risks. It is emphasized that separate waste collection is an important condition for creating a responsible "garbage culture" in society. Secondary methods (recycling) are the next stage, with mechanical, chemical, and thermal techniques used on the waste for processing in order to obtain an usable end result.

The main objective of the contributions for this Special Issue of Processes is to provide a view of the state of the art and the future prospects of Green Synthesis (Processing), with special emphasis on environmentally friendly, biocompatible nanoadsorbents and using natural renewable products or resources in order to support their valorization in environmental protection and sustainable development.

Prof. Dr. Eva Chmielewská
Prof. Dr. Craig Williams
Guest Editors

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Keywords

  • bioinspiration and biomimetics
  • sustainable life
  • reuse and recycling of water and human goods
  • green processing
  • nanomaterials
  • circular economy

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Published Papers (5 papers)

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Research

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16 pages, 3324 KiB  
Article
Research on the Harmless Treatment of Barium Slag Using Flue Gas Desulfurization Gypsum
by Yang Wan, Zhou Chen, Xiaohui Cao, Xin Song, Yu Zhan, Chunting Ma, Siqi Zhang and Wen Ni
Processes 2025, 13(1), 55; https://doi.org/10.3390/pr13010055 - 30 Dec 2024
Viewed by 628
Abstract
This study proposes an innovative method for the harmless treatment of barium slag using the industrial by-product Flue Gas Desulfurization Gypsum. Barium slag is a by-product of the barium carbonate production process, and due to its high content of barium ions and corrosive [...] Read more.
This study proposes an innovative method for the harmless treatment of barium slag using the industrial by-product Flue Gas Desulfurization Gypsum. Barium slag is a by-product of the barium carbonate production process, and due to its high content of barium ions and corrosive properties, it poses a significant threat to the environment and human health. It is classified as barium-containing hazardous waste (code HW47) in China. In this study, barium slag was optimally combined with FGD gypsum, utilizing a synergistic precipitation mechanism to solidify the easily leachable barium ions and form stable sulfate minerals. Mechanical and heavy metal leaching tests showed that the harmlessly treated barium slag had a certain compressive strength, and the concentration of barium ions in the leachate was below the national hazardous waste identification standards (100 mg/L) and the drinking water quality standards (0.7 mg/L). Microstructural analysis using X-ray diffraction, Fourier Transform Infrared Spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy indicated that FGD gypsum promotes the solidification of barium slag, and through the synergistic precipitation mechanism, low-solubility barium sulfate minerals are formed. This treatment method also has a low cost and good potential for resource utilization, providing effective technical support for the green treatment of industrial waste. Full article
(This article belongs to the Special Issue Advances in Wastewater and Solid Waste Treatment Processes)
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21 pages, 7683 KiB  
Article
Coffee-Waste-Based ZnCl2 Activated Carbon in High-Performance Supercapacitor Electrodes: Impact of Graphitization, Surface Morphology, Porosity and Conductivity
by Sami Mukhiemer, Allan Daraghmah, Heba Nassar, Shahzad Hussain, Hanyi Lim, Hyobin Han, Tae Woo Kim, Ameed N. Amireh and Hikmat S. Hilal
Processes 2024, 12(12), 2832; https://doi.org/10.3390/pr12122832 - 10 Dec 2024
Viewed by 718
Abstract
Activated carbon (AC) electrodes from coffee waste (CW) were earlier assessed in supercapacitors but showed lower supercapacitor performance in terms of specific capacity (Cs), specific power (Ps) or both, compared to other biowastes. This work describes how [...] Read more.
Activated carbon (AC) electrodes from coffee waste (CW) were earlier assessed in supercapacitors but showed lower supercapacitor performance in terms of specific capacity (Cs), specific power (Ps) or both, compared to other biowastes. This work describes how CW-based AC electrode performance may be improved if carefully prepared. Careful processing yields higher graphitization, carbon content (aromaticity), conductivity and porosity free of any residues. Thus, AC electrodes will exhibit higher Cs and Ps simultaneously. CW was first pyrolyzed (CPyrol) and then chemically activated by ZnCl2 (ACChem). Both materials were characterized using SEM, TEM, BET, FT-IR spectra, Raman spectra and XRD. The ACChem exhibited much higher graphitization, crystallinity, specific surface area (SSA), porosity and conductivity. From cyclic voltammetry, the ACChem electrode exhibited a Cs of 261 F/g, an energy density of 18.3 Wh/kg and a Ps of 360 W/kg at 0.33 A/g. From galvanostatic charge–discharge, there was a stable Cs of 150 F/g at 0.33 A/g over 5000 charge–discharge cycles. From electrochemical impedance spectroscopy, the Cs was ~180 F/g, with a low equivalent series resistance (ESR) of 0.56 Ω at a frequency of 0.01 Hz, compared to the literature. The ACChem electrode was superior to the CPyrol electrode and to earlier CW-based AC counterparts, with much lower resistance. Moreover, the electrode competed with other biowaste-based electrodes. Full article
(This article belongs to the Special Issue Advances in Wastewater and Solid Waste Treatment Processes)
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15 pages, 4471 KiB  
Article
Plasma Gasification of a Simulated Low-Level Radioactive Waste: Co, Cs, Sr, and Ce Retention Efficiency
by Juan Ariel Pullao, Franco Emmanuel Benedetto, Gian Franco Binetti Basterrechea, Leonardo Andrés Neira Poblete, Diana Carolina Lago and Miguel Oscar Prado
Processes 2024, 12(9), 1919; https://doi.org/10.3390/pr12091919 - 6 Sep 2024
Viewed by 826
Abstract
Thermal plasma is a versatile technology that can be used to treat various types of wastes, including vegetal and mineral oils, solvents, plastics, paper and cardboard, glasses, bricks and rocks, metals, clothes, and mixtures of these materials. In this study, we utilized a [...] Read more.
Thermal plasma is a versatile technology that can be used to treat various types of wastes, including vegetal and mineral oils, solvents, plastics, paper and cardboard, glasses, bricks and rocks, metals, clothes, and mixtures of these materials. In this study, we utilized a commercial plasma cutter as a thermal plasma source to decrease the volume of a simulated low-level radioactive mixed solid waste. The simulated waste included papers, plastics, clothes, gloves, metals, and stable Co, Cs, Sr, and Ce additives as surrogates of 60Co, 137Cs, 90Sr, and 144Ce, respectively, the latter being typical contaminants in nuclear LLW. As a result of the process, two products were obtained: a solid phase, on which we focused this work, and a gaseous phase. To retain as many as surrogates as possible in the solid final phase, crushed glass from broken bottles was included as a vitrification additive to the original waste. After undergoing heat treatment, a dense vitreous slag was produced along with ashes. The process resulted in a volume reduction of 70%, indicating the successful gasification of organic excess materials. The surrogate elements were retained in the process and were found in the ashes composition: Co (3.4% w/w), Cs (37.7% w/w), and Ce (0.6% w/w) and in the glass matrix composition of Co, Cs, Sr and Ce: 72.4 ± 14.7, 32 ± 18.2, 125.3 ± 31.6, 80 ± 13.1% w/w, respectively. For the actual experimental conditions, retention efficiencies were estimated for cobalt (Co) at 72.4 ± 14.7%, cerium (Ce) at 80 ± 13.1%, strontium (Sr) at 125.3 ± 31.6%, and notably cesium (Cs) at 32 ± 18.2%. Full article
(This article belongs to the Special Issue Advances in Wastewater and Solid Waste Treatment Processes)
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16 pages, 2045 KiB  
Article
Plant-Based Substrates for the Production of Iron Bionanoparticles (Fe-BNPs) and Application in PCB Degradation with Bacterial Strains
by Marcela Tlčíková, Hana Horváthová, Katarína Dercová, Michaela Majčinová, Mariana Hurbanová, Katarína Turanská and Ľubomír Jurkovič
Processes 2024, 12(8), 1695; https://doi.org/10.3390/pr12081695 - 13 Aug 2024
Viewed by 1173
Abstract
Removing polychlorinated biphenyls (PCBs) from the environment is an important process for the protection of biota. This work examines three different approaches to the degradation of such contaminants. The first involves the use of iron bionanoparticles (Fe-BNPs) prepared through green synthesis from selected [...] Read more.
Removing polychlorinated biphenyls (PCBs) from the environment is an important process for the protection of biota. This work examines three different approaches to the degradation of such contaminants. The first involves the use of iron bionanoparticles (Fe-BNPs) prepared through green synthesis from selected plant matrices. The second approach entails the use of the bacteria Stenotrophomonas maltophilia (SM) and Ochrobactrum anthropi (OA) isolated from a PCB-contaminated area, Strážsky canal, located in the Slovak republic, which receives efflux of canal from Chemko Strážske plant, a former producer of PCB mixtures. The third approach combines these two methods, employing a sequential hybrid two-step application of Fe-BNPs from the plant matrix followed by the application of bacterial strains. Fe-BNPs are intended to be an eco-friendly alternative to synthetic nanoscale zero-valent iron (nZVI), which is commonly used in many environmental applications. This work also addresses the optimization parameters for using nZVI in PCB degradation, including the pH of the reaction, oxygen requirements, and dosage of nZVI. Pure standards of polyphenols (gallic acid, GA) and flavonoids (quercetin, Q) were tested to produce Fe-BNPs using green synthesis at different concentrations (0.1, 0.3, 0.5, 0.8, and 1 g.L−1) and were subsequently applied to the PCB degradation experiments. This step monitored the minimum content of bioactive substances needed for the synthesis of Fe-BNPs and their degradation effects. Experimental analysis indicated that among the selected approaches, sequential nanobiodegradation appears to be the most effective for PCB degradation, specifically the combination of Fe-BNPs from sage and bacteria SM (75% degradation of PCBs) and Fe-BNPs from GA (0.3 g.L−1) with bacteria OA (92% degradation of PCBs). Full article
(This article belongs to the Special Issue Advances in Wastewater and Solid Waste Treatment Processes)
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Review

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25 pages, 1583 KiB  
Review
Biosand Reactors for Municipal and Industrial Wastewater Treatment: Status Quo, Challenges and Opportunities
by Pamela Jean Welz
Processes 2024, 12(4), 641; https://doi.org/10.3390/pr12040641 - 23 Mar 2024
Cited by 4 | Viewed by 1394
Abstract
Biosand reactors (BSRs), alternatively known as slow or biological sand filters, are passive systems that are used to remove contaminants from domestic wastewater, industrial wastewater and drinking water. This review focuses specifically on their application for remediation of industrial effluent and sewage-containing municipal [...] Read more.
Biosand reactors (BSRs), alternatively known as slow or biological sand filters, are passive systems that are used to remove contaminants from domestic wastewater, industrial wastewater and drinking water. This review focuses specifically on their application for remediation of industrial effluent and sewage-containing municipal and household effluent. The relationships between the physicochemical characteristics of the sand grains (size, size distribution, shape, chemical composition) and the hydraulic conductivity of the sand employed in BSFs are critically discussed in relationship to the achievable loading rates and hydraulic retention times. The modes of operation and influence of the functional microbial biomass as well as biodegradable and recalcitrant particulates on these parameters is comprehensively reviewed. Finally, the bioremediation of sewage-based and industrial wastewater is examined. This includes an account of the biotic and abiotic removal mechanisms and the limitations of BSRs for removal of pollutants such as phosphorus/phosphate and nitrates/nitrites. The removal mechanisms and removal efficiencies of macronutrients, micropollutants, fecal indicators and other microorganisms such as antibiotic-resistant bacteria in BSRs are discussed. Full article
(This article belongs to the Special Issue Advances in Wastewater and Solid Waste Treatment Processes)
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