Editorial

2 pages, 188 KiB

Open AccessEditorial

Special Issue on Frontier Research in Waters, Air and Wastes

by Marco Carnevale Miino, Alessandro Abbà and Maria Cristina Collivignarelli

Appl. Sci. 2023, 13(7), 4278; https://0-doi-org.brum.beds.ac.uk/10.3390/app13074278 - 28 Mar 2023

Viewed by 743

To solve global problems about water and air pollution and waste production, research plays a key and essential role [...] Full article

(This article belongs to the Special Issue Frontier Research in Waters, Air and Wastes)

Research

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17 pages, 4644 KiB

Open AccessArticle

Implementing Circular Economy Techniques for the Optimal Management of Recyclable Solid Waste Using the M-GRCT Decision Support Model

by Camilo-A. Vargas-Terranova, Javier Rodrigo-Ilarri, María-Elena Rodrigo-Clavero and Alejandro Parra-Saad

Appl. Sci. 2022, 12(16), 8072; https://0-doi-org.brum.beds.ac.uk/10.3390/app12168072 - 12 Aug 2022

Cited by 3 | Viewed by 1303

Abstract

This article analyzes the implementation of a circular economy model for the management of reusable solid waste in the Colombian municipalities of Arbeláez (province of Cundinamarca) and Tibasosa (province of Boyacá). The analysis is conducted using M-GRCT, a circular economy decision support model [...] Read more.

This article analyzes the implementation of a circular economy model for the management of reusable solid waste in the Colombian municipalities of Arbeláez (province of Cundinamarca) and Tibasosa (province of Boyacá). The analysis is conducted using M-GRCT, a circular economy decision support model for the design of recyclable waste management systems in low-income municipalities. The model allows for performing calculations on a set of two scenarios integrating a sociocultural dynamics assessment—this being a characteristic feature of this type of municipalities. Results show that both the linear and circular models of waste management are economically viable. However, the particular conditions of each municipality, the tariff system, the number of subscribers and the variations in costs and inflation in each municipality affect the results of economic viability. In addition, the waste production scale and the volumes of recoverable waste also affect the results. All these factors are reflected in the scenarios analyzed. In terms of economic viability, the circular model presents better results in Arbeláez, while in the municipality of Tibasosa, the best results are obtained with a linear economy approach. Full article

(This article belongs to the Special Issue Frontier Research in Waters, Air and Wastes)

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12 pages, 3451 KiB

Open AccessArticle

An Evidence-Based Survey on Full-Scale Membrane Biological Reactors: Main Technical Features and Operational Aspects

by Mentore Vaccari, Alessandro Abbà, Giorgio Bertanza and Carlo Collivignarelli

Appl. Sci. 2022, 12(13), 6559; https://0-doi-org.brum.beds.ac.uk/10.3390/app12136559 - 28 Jun 2022

Cited by 2 | Viewed by 1253

Abstract

This paper presents the results of a survey on full-scale membrane biological reactors (MBRs) wastewater treatment plants (WWTPs) in Italy. Alongside the main technical characteristics of the Italian MBR plants, the opinions of the plant managers on the operational advantages and disadvantages are [...] Read more.

This paper presents the results of a survey on full-scale membrane biological reactors (MBRs) wastewater treatment plants (WWTPs) in Italy. Alongside the main technical characteristics of the Italian MBR plants, the opinions of the plant managers on the operational advantages and disadvantages are described. As reported by the MBR technology suppliers, approximately 290 MBR municipal or industrial WWTPs are in operation in Italy, out of which 242 were studied in this survey. Data from more than one hundred municipal WWTPs were collected; these account for a total capacity of about 2,000,000 population equivalent (PE), which corresponds to 3% of the total organic load treated by the Italian WWTPs with secondary and advanced treatment. Usually, small installations adopt the flat-sheet rather than hollow-fiber membrane configuration. The main reasons why the MBR technology has been preferred to other options are its potential to be used for increasing the treatment capacity of existing plants and its compactness. Moreover, the followed operational advantages have been highlighted: easiness to comply with the discharge limits, removal of pathogens without specific disinfection units, possibility of internal reuse of the effluent, and process automation. Membrane fouling and plant shutdown have been recorded as the most relevant troubles, the last one indeed occurring only occasionally or rarely. Full article

(This article belongs to the Special Issue Frontier Research in Waters, Air and Wastes)

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22 pages, 17964 KiB

Open AccessArticle

Removal of Methylene Blue by Metal Oxides Supported by Oily Sludge Pyrolysis Residues

by Jinling Li, Lei Han, Tiantian Zhang, Chengtun Qu, Tao Yu and Bo Yang

Appl. Sci. 2022, 12(9), 4725; https://0-doi-org.brum.beds.ac.uk/10.3390/app12094725 - 07 May 2022

Cited by 4 | Viewed by 1490

Abstract

As a typical pollutant, methylene blue poses a serious threat to the environment and human health. Oily sludge pyrolysis residue loaded with metal oxides could be used to prepare composite materials, which is not only an effective way to treat oily sludge, but [...] Read more.

As a typical pollutant, methylene blue poses a serious threat to the environment and human health. Oily sludge pyrolysis residue loaded with metal oxides could be used to prepare composite materials, which is not only an effective way to treat oily sludge, but also a possible method to treat methylene blue pollutants. In this paper, composite materials (AC-CuO, AC-ZnO, and AC-TiO₂) were prepared by oily sludge pyrolysis residue-loaded CuO, ZnO, and TiO₂ directly, and characterized by XRD, SEM, EDS, BET, FT-IR, and XPS, and it was shown that the metal oxides were successfully supported on the pyrolysis residue. Then, the composite materials were applied to the removal of methylene blue solution. The removal effect of composite materials on methylene blue with respect to the impregnation time, impregnation ratio and dosage, and the contact time and number of regenerations were investigated, and the removal parameters were optimized by response surface methodology. The removal process for methylene blue was described by applying Lagergren, McKay, Langmuir isotherm, Freundlish isotherm and intraparticle diffusion models. According to the response surface methodology and the main factors affecting the removal effect of methylene blue, the results indicate that the removal effect of 5 mg/L methylene blue could reach 95.28%, 94.95%, and 96.96%, respectively, and the corresponding removal capacities were 4.76, 4.75, and 4.85 mg/g. In addition, kinetic studies showed that the removal process of methylene blue was mainly constituted by chemical adsorption. The intraparticle diffusion showed that the removal of methylene blue may be controlled by both liquid film diffusion and intraparticle diffusion. The isotherms showed that the adsorption sites of composites for methylene blue were uniformly distributed and had the same affinity. Furthermore, regeneration experiments showed that the composite materials were stable and had relatively reusability. Full article

(This article belongs to the Special Issue Frontier Research in Waters, Air and Wastes)

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19 pages, 4654 KiB

Open AccessArticle

Study of the Dissolution of Stainless-Steel Slag Minerals in Different Acid Environments to Promote Their Use for the Treatment of Acidic Wastewaters

by Mattia De Colle, Ross Kielman, Andreas Karlsson, Andrey Karasev and Pär G. Jönsson

Appl. Sci. 2021, 11(24), 12106; https://0-doi-org.brum.beds.ac.uk/10.3390/app112412106 - 19 Dec 2021

Cited by 2 | Viewed by 1842

Abstract

Several stainless-steel slags have been successfully employed in previous studies as substitutes for lime in the treatment of industrial acidic wastewaters. This study deepens the knowledge of such application, by analyzing the neutralizing capacity of different slags related to their mineral compositions. To [...] Read more.

Several stainless-steel slags have been successfully employed in previous studies as substitutes for lime in the treatment of industrial acidic wastewaters. This study deepens the knowledge of such application, by analyzing the neutralizing capacity of different slags related to their mineral compositions. To do so, firstly the chemical and mineral compositions of all the slag samples are assessed. Then, 0.5 g, 1 g, 2 g of each slag and 0.25 g and 0.5 g of lime are used to neutralize 100 g of 0.1 M HCl or HNO₃ solutions. After the has neutralization occurred, the solid residues are extracted and analyzed using XRD spectroscopy. Then, the solubility of the minerals is assessed and ranked, by comparing the XRD spectra of the residues with the obtained pH values. The results show that minerals such as dicalcium silicate and bredigite are highly soluble in the selected experimental conditions, while minerals such as merwinite and åkermanite, only partially. Moreover, Al-rich slags seem to perform poorly due to the formation of hydroxides, which generate extra protons. However, when the weight of slag is adequately adjusted, Al-rich slags can increase the pH values to higher levels compared to the other studied slags. Full article

(This article belongs to the Special Issue Frontier Research in Waters, Air and Wastes)

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11 pages, 2304 KiB

Open AccessFeature PaperArticle

End-of-Life Tyres: Comparative Life Cycle Assessment of Treatment Scenarios

by Isabella Bianco, Deborah Panepinto and Mariachiara Zanetti

Appl. Sci. 2021, 11(8), 3599; https://0-doi-org.brum.beds.ac.uk/10.3390/app11083599 - 16 Apr 2021

Cited by 25 | Viewed by 3726

Abstract

Waste tyres and their accumulation is a global environmental concern; they are not biodegradable, and, globally, an estimated 1.5 billion are generated annually. Every year around 350,000 tons of end-of-life tyres (ELT) are managed in Italy, collected from cars, two-wheeled vehicles, trucks, up [...] Read more.

Waste tyres and their accumulation is a global environmental concern; they are not biodegradable, and, globally, an estimated 1.5 billion are generated annually. Every year around 350,000 tons of end-of-life tyres (ELT) are managed in Italy, collected from cars, two-wheeled vehicles, trucks, up to large quarry vehicles and agricultural vehicles. ELTs are collected and sent for material or energy recovery, in line with the circular economy principles. This paper investigates the environmental impacts of two common scenarios of ELT treatments. Specifically, it is analysed the recycling of crumb rubber (CR, deriving from the tyre shredding) for the composition of bituminous mixtures for the wearing course of roads. This scenario is compared with the energy recovery route in a dedicated incinerator. To this aim the standardised methodology of Life Cycle Assessment (ISO 14040-44) is employed. Results shows that for most part of the impact categories analysed, the material recovery presents higher environmental benefits if compared with energy recovery. Full article

(This article belongs to the Special Issue Frontier Research in Waters, Air and Wastes)

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Review

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13 pages, 609 KiB

Open AccessReview

Reuse or Disposal of Waste Foundry Sand: An Insight into Environmental Aspects

by Flavio Cioli, Alessandro Abbà, Carlotta Alias and Sabrina Sorlini

Appl. Sci. 2022, 12(13), 6420; https://0-doi-org.brum.beds.ac.uk/10.3390/app12136420 - 24 Jun 2022

Cited by 10 | Viewed by 2854

Abstract

From a circular economy perspective, the recovery and reuse of waste plays a fundamental role. Foundries purchase hundreds of millions of siliceous sands every year to create molds and cores that give shape to the casting. These sands, after several uses, become waste [...] Read more.

From a circular economy perspective, the recovery and reuse of waste plays a fundamental role. Foundries purchase hundreds of millions of siliceous sands every year to create molds and cores that give shape to the casting. These sands, after several uses, become waste that must be properly recovered or disposed of; they are called waste foundry sands (WFS). The reuse of WFS leads to a reduction in: (i) the consumption of raw materials; (ii) the emissions into the atmosphere; and (iii) the amount of waste sent to landfill—on the other hand, the impact that their use generates on the environment and human health must be carefully assessed. Leaching tests are a fundamental tool for establishing the hazardousness of a waste and its release of contaminants into the environment. This paper presents an analysis of the scientific literature regarding the chemical characteristics of WFS and their release following leaching tests carried out in the laboratory; the environmental standards adopted by the countries that have issued guidelines regarding the reuse of WFS will also be presented. Full article

(This article belongs to the Special Issue Frontier Research in Waters, Air and Wastes)

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26 pages, 2308 KiB

Open AccessReview

Rice Industry By-Products as Adsorbent Materials for Removing Fluoride and Arsenic from Drinking Water—A Review

by Maria Cristina Collivignarelli, Sabrina Sorlini, Chiara Milanese, W. A. M. A. N. Illankoon, Francesca Maria Caccamo and Silvia Calatroni

Appl. Sci. 2022, 12(6), 3166; https://0-doi-org.brum.beds.ac.uk/10.3390/app12063166 - 20 Mar 2022

Cited by 11 | Viewed by 4249

Abstract

In drinking water, high concentrations of fluoride and arsenic can have adverse effects on human health. Waste deriving from the rice industry (rice husk, rice straw, rice bran) can be promising adsorbent materials, because they are (i) produced in large quantities in many [...] Read more.

In drinking water, high concentrations of fluoride and arsenic can have adverse effects on human health. Waste deriving from the rice industry (rice husk, rice straw, rice bran) can be promising adsorbent materials, because they are (i) produced in large quantities in many parts of the world, (ii) recoverable in a circular economy perspective, (iii) at low cost if compared to expensive conventional activated carbon, and (iv) easily manageable even in developing countries. For the removal of fluoride, rice husk and rice straw allowed to obtain adsorption capacities in the range of 7.9–15.2 mg/g. Using rice husk for arsenic adsorption, excellent results were achieved with adsorption capacities above 19 mg/g. The best results both for fluorides and arsenic (>50 mg/g) were found with metal- or chemical-modified rice straw and rice husk. Identifying the next steps of future research to ensure the upscaling of biochar from recovered by-products, it is fundamental to perform: (i) tests on real waters for multicomponent adsorption; (ii) experiments with pilot plants in continuous operation; (iii) cost analysis/real applicability of modification treatments such as metal coupling or chemical synthesis; (iv) more studies on the biochar stability and on its regeneration or recovery after use. Full article

(This article belongs to the Special Issue Frontier Research in Waters, Air and Wastes)

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