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Clean Technologies, Volume 8, Issue 2

2026 April - 34 articles

Cover Story: Municipal wastewater treatment is shifting toward integrated strategies for the simultaneous removal of carbon and nutrients. This study explores the optimization of an acidogenic anaerobic process in a sequencing batch reactor (SBR) to enhance the conversion of organic matter into volatile fatty acids (VFAs), providing a readily biodegradable carbon source. By controlling temperature, the system promotes efficient carbon transformation pathways that support downstream nitrogen and phosphorus removal. A validated kinetic model describes process dynamics and enables optimization of operating conditions. The results highlight the potential of SBR-based configurations to achieve efficient, sustainable, and optimized carbon and nutrient removal, reducing dependence on external carbon sources and improving overall treatment performance in sensitive environments. View this paper
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Articles (34)

  • Article
  • Open Access
1,191 Views
24 Pages

Recycling of Sustainable Automotive Structural Composites via Pyrolysis, Technical and Climate Impact Evaluation

  • Ann-Christine Johansson,
  • Rebecka Nordsvahn,
  • André Selander,
  • Torun Hammar,
  • Jesper Eman and
  • Magdalena Juntikka

Sustainable structural composites can significantly lower vehicle-related emissions. To evaluate the recycling of different composite materials, laboratory-scale pyrolysis was conducted and assessed both technically and environmentally. Two demonstra...

(This article belongs to the Special Issue Selected Papers from Circular Materials Conference 2025)
  • Article
  • Open Access
1 Citations
1,665 Views
36 Pages

Emission Reduction Strategies for Cement Production in Mexico: A Scenario Analysis

  • Mariana Murrieta-Melchor,
  • Stephany Isabel Vallarta-Serrano,
  • Edgar Santoyo-Castelazo and
  • Sergio Alberto Navarro-Tuch

As the world faces the challenge of mitigating climate change, energy- and emissions-intensive industrial processes must be addressed urgently worldwide. The cement production industry accounts for over 8% of global greenhouse gas (GHG) emissions fro...

  • Review
  • Open Access
2 Citations
2,093 Views
29 Pages

Posidonia oceanica Ashore Waste Biomass: State-of-the-Art and Valorisation Perspectives Within the Circular Economy Framework

  • Manuel Hernández-Escaño,
  • Rafael Borja,
  • José Carlos García-Gómez and
  • Francisco Raposo

The accumulation of dead leaves from the Mediterranean seagrass Posidonia oceanica on beaches is a natural process that results in the formation of banquettes and, in some areas, spherical debris known as aegagropiles. These structures provide essent...

(This article belongs to the Collection Review Papers in Clean Technologies)
  • Article
  • Open Access
6 Citations
2,184 Views
26 Pages

Energy Recovery and Techno-Economic Analysis of Hydrothermal Carbonization and Anaerobic Digestion of Food Waste

  • Ahmed Mohammed Inuwa,
  • Victor Oluwafemi Fatokun,
  • Emmanuel Kweinor Tetteh,
  • Sudesh Rathilal and
  • Usman Mohammed Aliyu

The sustainable valorization of food waste is essential for advancing the circular bioeconomy and reducing the environmental impacts of organic waste disposal. This study presents an integrated approach combining hydrothermal carbonization (HTC) and...

(This article belongs to the Special Issue Valorization of Agrifood By-Products and Innovation in Sustainable Biological Resources)
  • Article
  • Open Access
1,748 Views
18 Pages

Air flotation is widely used in wastewater treatment for the removal of emulsified oils and suspended solids. The complex flow disturbances generated during the flotation process play a critical role in determining separation efficiency. This study e...

(This article belongs to the Topic Soil/Sediment Remediation and Wastewater Treatment)
  • Article
  • Open Access
1 Citations
1,390 Views
20 Pages

A Comprehensive Evaluation of Produced-Water Reuse Potential for Cementing Operations in the Delaware Basin

  • Kazhi Hawrami,
  • Bassel Eissa,
  • Abdulrahman Shahin,
  • Elvin Hajiyev,
  • Hossein Emadi and
  • Marshall Watson

Freshwater demand for cementing operations in the Delaware Basin continues to increase with expanding unconventional development, creating a high demand for an alternative source of water. This study develops a chemistry screening and operational fra...

  • Article
  • Open Access
3 Citations
1,622 Views
16 Pages

Enhancing Photocatalytic Performance of ZnO Nanoparticles Through Er/Al Co-Doping for Solar-Driven Environmental Remediation

  • Raúl Bahamonde Soria,
  • Jefferson Estupiñan,
  • Irma Gonza,
  • Monserrat Naranjo,
  • Billy D. Chinchin-Piñan,
  • Lucia E. Manangón,
  • Katherine Vaca,
  • Martha Romero-Bastidas,
  • Henry Pupiales and
  • Patricia Luis
  • + 1 author

Improving the absorption of visible light in photocatalysts could enhance photocatalytic reactions and reduce energy consumption, particularly in sunny regions like Ecuador. This study reports the synthesis of ZnO and ZnO nanoparticles doped with 1.5...

  • Review
  • Open Access
1 Citations
1,456 Views
20 Pages

This article presents a systematic literature review on methane (CH4) emissions from municipal solid waste (MSW) disposal sites and their implications for footprint outcomes. This review followed a PRISMA 2020 screening logic using Scopus and Science...

  • Review
  • Open Access
2 Citations
4,681 Views
50 Pages

Artificial intelligence presents a critical paradox for clean technology: while enabling unprecedented environmental optimization, AI deployment demands massive resource inputs that threaten to offset benefits. As global AI infrastructure investment...

  • Article
  • Open Access
4 Citations
1,231 Views
42 Pages

Sustainable hydrogen production in water-scarce regions poses critical environmental challenges due to limited freshwater availability and the energy intensity of seawater treatment. This study examines the environmental trade-offs of providing water...

  • Article
  • Open Access
2 Citations
1,610 Views
17 Pages

Natural Deep Eutectic Solvents for the Green Extraction of Betulin from Birch Bark: Chemical Characterization and Evaluation of Antioxidant Activity

  • Feyisayo O. Adepoju,
  • Vadim A. Shevyrin,
  • Elena G. Kovaleva,
  • Alicia C. Mondragón,
  • Alberto Cepeda and
  • José Manuel Miranda

Natural deep eutectic solvents (NADESs) have emerged as promising green alternatives to conventional solvents for the extraction of bioactive compounds from plant materials. In this study, eight natural deep eutectic solvents were synthesized and eva...

  • Review
  • Open Access
3 Citations
3,371 Views
18 Pages

Smart-Farm-Integrated Cold Thermal Energy Storage (CTES) Systems for Clean, Solar-Powered Rural Postharvest Cooling: A Review

  • Ahsan Mehtab,
  • Hong-Seok Mun,
  • Eddiemar B. Lagua,
  • Hae-Rang Park,
  • Jin-Gu Kang,
  • Young-Hwa Kim,
  • Md Kamrul Hasan,
  • Md Sharifuzzaman,
  • Sang-Bum Ryu and
  • Chul-Ju Yang

Cold thermal energy storage (CTES) has emerged as a critical clean-energy technology for enhancing postharvest management in rural agricultural supply chains, where losses often exceed 20–40% due to inadequate cooling infrastructure and unrelia...

  • Article
  • Open Access
1 Citations
863 Views
16 Pages

This study explores a circular bioeconomy strategy for microbrewery waste by characterizing and valorizing its primary waste streams: sugar mash water (A), spent yeast with hops (B), spent yeast without hops (C), and alkaline cleaning wastewater (D)....

  • Article
  • Open Access
6 Citations
2,108 Views
18 Pages

Beyond the C/N Ratio: The Critical Role of Carbon Bioavailability in Aerobic Composting of Agricultural Waste

  • Bo Shen,
  • Xiaoyan Zheng,
  • Lili Zheng,
  • Yang Yang,
  • Dao Xiao,
  • Zhanwu Sheng,
  • Yiqiang Wang and
  • Binling Ai

The initial carbon-to-nitrogen (C/N) ratio is a fundamental parameter for aerobic composting, with a generally recommended optimal range of 25:1 to 30:1. However, in practical applications, the optimal C/N ratio often deviates from the recommended va...

(This article belongs to the Topic Waste Management Through Composting: Benefits, New Insights and Challenges, 2nd Edition)
  • Article
  • Open Access
1 Citations
1,721 Views
21 Pages

Developing far-offshore wind power integrated with hydrogen production represents a critical pathway for China’s energy decarbonization. However, the investment prospects of off-grid offshore wind-to-hydrogen projects remain highly uncertain du...

  • Article
  • Open Access
2,519 Views
38 Pages

Microwave Depolymerization of Various Plastic Wastes—Quarter-Scale Testing

  • Andrzej Piotrowicz,
  • Janusz Kolczyński,
  • Mirosław Kostrzewa,
  • Wojciech Kaczmarek and
  • Bogdan Samojeden

Microwave-assisted depolymerization (MD) of heterogeneous postconsumer plastics was carried out in a quarter-scale reactor to evaluate product composition and the influence of feedstock type on oil quantity and quality. Various waste streams, includi...

  • Article
  • Open Access
1 Citations
1,013 Views
13 Pages

Valorization of Paper Pulp Mill Sludge for Protease Production by Indigenous Bacillus tropicus P4

  • Vu-Mai-Linh Nguyen,
  • Adama Ndao,
  • Jean-François Blais and
  • Kokou Adjallé

This study explores the potential of using paper pulp mill sludge (PPMS) as an economical substrate for producing high-value protease enzymes with an indigenous bacterial strain, Bacillus tropicus P4. Isolated directly from PPMS, B. tropicus P4 showe...

  • Article
  • Open Access
1,325 Views
16 Pages

The environmental crisis and the growing need to reduce solid waste make it imperative to adopt integrated, scientifically sound, and environmentally friendly solid waste management practices in order to ensure a sustainable future. This study presen...

(This article belongs to the Special Issue Innovative Approaches to Sustainable Design, Recovery, and Circular Management of Solid Waste)
  • Article
  • Open Access
1 Citations
1,339 Views
19 Pages

Resource Recycling and Wastewater Remediation: Application of Turning Metal Scrap as Anode in Electrochemical Treatment of Soluble Cutting Fluids

  • Hyung-kyu Lee,
  • Go-eun Kim,
  • Seong-ho Jang,
  • Ho-min Kim,
  • Byung-gil Jung,
  • Young-chae Song and
  • Won-ki Lee

Soluble cutting fluids (SCFs) from metalworking processes pose significant treatment challenges. Here, SCFs were treated using a monopolar electrochemical (EC) system, using turning scrap generated from metalworking operations as the anode. The syste...

(This article belongs to the Special Issue Innovative Advanced Oxidation and Adsorption Technologies for Contaminants of Emerging Concern in Water and Wastewater)
  • Article
  • Open Access
1 Citations
2,046 Views
20 Pages

CFD Simulation of a Vertical-Axis Savonius-Type Micro Wind Turbine Using Meteorological Data from an Educational Environment

  • José Cabrera-Escobar,
  • Carlos Mauricio Carrillo Rosero,
  • César Hernán Arroba Arroba,
  • Santiago Paúl Cabrera Anda,
  • Catherine Cabrera-Escobar and
  • Raúl Cabrera-Escobar

This study presents a two-dimensional computational fluid dynamics analysis of a vertical-axis Savonius-type wind turbine under atmospheric conditions representative of an educational environment located in the Ecuadorian Andean region. Unlike previo...

  • Article
  • Open Access
1 Citations
1,069 Views
15 Pages

Graphene as a Soil Amendment for the Mitigation of Fungicide Kresoxim-Methyl Pollution

  • Kamyar Shirvanimoghaddam,
  • Agnieszka Krzyszczak-Turczyn,
  • Ilona Sadok,
  • Bożena Czech,
  • Omid Zabihi and
  • Minoo Naebe

The global demand for high-quality food is rising due to the increasing population, necessitating intensive farming practices that often involve the extensive use of pesticides, which can accumulate in soils and enter the food chain. This study explo...

  • Article
  • Open Access
1,835 Views
24 Pages

Adsorption of Methylene Blue Using a Novel Adsorbent: Silk Fibroin Nanoparticles

  • María-Isabel Aguilar,
  • Mercedes Lloréns,
  • Víctor-Francisco Meseguer,
  • Juan-Francisco Ortuño,
  • Ana-Belén Pérez-Marín and
  • Rafael Valentín

Adsorption is an effective method frequently used for removing contaminants, including dyes, from liquid effluents. This study uses silk fibroin nanoparticles produced by the Bombyx mori moth as an adsorbent material to remove methylene blue dye from...

  • Article
  • Open Access
2 Citations
2,649 Views
36 Pages

Low-Carbon and Bioclimatic Design for a Sustainable Interpretation and Research Center for Ecosystem Conservation in Madre de Dios, Peru

  • Jesica Vilchez Cairo,
  • Tessa Yazmin Sanchez Grandez,
  • Danai Noelia Hidalgo Cabrera,
  • Luis Fernando Medrano Canchari,
  • Julio Rodrigo Tornero Loayza,
  • Doris Esenarro,
  • Carlos Manuel Cavani Grau and
  • Miguel Ramón Cobeñas Cabrera

The natural resources and local communities of Madre de Dios, Peru, face severe environmental degradation due to illegal mining, deforestation, and the expansion of agricultural activities, threatening one of the most ecologically sensitive regions o...

(This article belongs to the Topic Low-Carbon Materials and Green Construction)
  • Article
  • Open Access
1,784 Views
22 Pages

A Comparative Case Study: Cradle-to-Grave LCA for Asphalt Mixtures Containing RAP and WMA

  • Ibrahim Elnaml,
  • Louay N. Mohammad,
  • Heather Dylla,
  • Moses Akentuna and
  • Samuel Cooper

The U.S. transportation section contributed a third of the national Greenhouse Gas (GHG) emissions in 2022. As such, the Louisiana Department of Transportation and Development (DOTD) initiated federally funded efforts to create Life Cycle Assessment...

  • Review
  • Open Access
6 Citations
4,442 Views
42 Pages

Recent Advances in Renewable Hydrogen Purification Technologies: A General Review

  • José Copa Rey,
  • Catarina Nobre,
  • Bruna Rijo,
  • Andrei Longo,
  • Paulo Brito and
  • Cecilia Mateos-Pedrero

Renewable hydrogen purification is a critical yet often underemphasised step in enabling its use as a clean energy carrier. Hydrogen produced from biomass-based thermochemical and biological routes typically contains CO2, CO, CH4, H2S, and other impu...

  • Article
  • Open Access
4 Citations
2,381 Views
17 Pages

Catalytic Upgrading of Microalgae-Based Bio-Oils for Sustainable Jet Fuel Production

  • Bruna Thomazinho França,
  • Filipe Paradela,
  • Marta Martins,
  • Ana Luísa Fernando,
  • Alberto Reis and
  • Paula Costa

The transition to sustainable energy systems has intensified the search for renewable alternatives to reduce greenhouse gas emissions and reliance on fossil fuels. In this context, microalgae have emerged as a promising third-generation feedstock for...

  • Article
  • Open Access
1 Citations
1,514 Views
24 Pages

Optimization and Scale-Up of Tuber spp. Growth on Olive Mill Wastewater and Expired Glucose Syrup Substrates

  • Ilias Diamantis,
  • Gabriel Vasilakis,
  • Seraphim Papanikolaou,
  • Nikolaos G. Stoforos and
  • Panagiota Diamantopoulou

The present study investigates the potential of olive mill wastewater (OMW), supplemented with expired commercial glucose syrup, as a sustainable substrate for the submerged cultivation of Tuber spp. wild mushrooms. OMW contains considerable quantiti...

(This article belongs to the Special Issue Biomass Valorization and Sustainable Biorefineries)
  • Article
  • Open Access
1,862 Views
16 Pages

Simultaneous Removal of Microplastics and Total Suspended Solids from Wastewater via a Novel Organosilane-Induced Agglomeration–Fixation Method at a Two-Stage Treatment Plant in Greece

  • Michael Toni Sturm,
  • Daphne Argyropoulou,
  • Pieter Ronsse,
  • Anika Korzin,
  • Dennis Schober,
  • Erika Myers,
  • Antonis G. Eleftheriou,
  • Ioannis Lelekis,
  • Andriani Galani and
  • Katrin Schuhen

This study evaluated the performance of a pilot unit for the combined removal of microplastics and total suspended solids at the municipal wastewater treatment plant of Mykonos, Greece. The pilot unit was installed downstream of the two-stage convent...

(This article belongs to the Collection Water and Wastewater Treatment Technologies)
  • Article
  • Open Access
1 Citations
1,764 Views
18 Pages

CO2 Capture by Hydrotalcite-Derived Sorbents in Pressure Swing Adsorption for Sorption-Enhancing

  • Barbara Malsegna,
  • Andrea Di Giuliano,
  • Greta D’Antonio and
  • Katia Gallucci

This work investigated hydrotalcite-derived sorbents for CO2 capture at 350 °C, 10 or 14 bar, and 38.5 vol% CO2 in wet or dry gas flow under dynamic Pressure Swing Adsorption (PSA) in a packed-bed laboratory reactor. The chosen conditions enabled a p...

(This article belongs to the Special Issue Green Solvents and Materials for CO2 Capture)
  • Review
  • Open Access
5 Citations
2,890 Views
33 Pages

From Biomass to Biofabrication: Advances in Substrate Treatment Technologies for Fungal Mycelium Composites

  • Musiliu A. Liadi,
  • Tawakalt O. Ayodele,
  • Abodunrin Tijani,
  • Ibrahim A. Bello,
  • Niloy Chandra Sarker,
  • C. Igathinathane and
  • Hammed M. Ademola

Mycelium-based composites (MBCs) have emerged as promising biofabricated materials that align with circular economy and clean technology goals by utilizing fungal networks to transform lignocellulosic residues into functional, biodegradable composite...

(This article belongs to the Topic Advanced Composite Materials)
  • Article
  • Open Access
1 Citations
2,337 Views
15 Pages

Thermal Behavior Analysis of Bis(2-hydroxyethyl) Terephthalate for Recovery from Polyethylene Terephthalate Glycolysis

  • Steffi Wünsche,
  • Vico Tenberg,
  • Arulselvan Ponnudurai,
  • Erik Temmel and
  • Heike Lorenz

In recent years, sustainability and the concept of a circular economy have grown in importance within almost all industrial sectors. Especially in the chemical industry, recycling of polymer waste streams has become an important pathway to avoid plas...

  • Article
  • Open Access
1,731 Views
22 Pages

Biological wastewater treatment relies primarily on activated sludge and anaerobic digestion for the removal of organic matter. In urban wastewater treatment plants discharging into eutrophication-sensitive environments, the simultaneous removal of c...

(This article belongs to the Collection Water and Wastewater Treatment Technologies)
  • Article
  • Open Access
1,588 Views
21 Pages

Integrating Coagulation and Flotation via Hydrodynamic Cavitation: The Key Role of Venturi Divergent Angle for Humic Substance Removal

  • Fausto de Souza Pagan,
  • Marcos Vinícius Mateus,
  • Thiago Vinicius Ribeiro Soeira,
  • Mário Sérgio da Luz,
  • Deusmaque Carneiro Ferreira,
  • Rodrigo Moruzzi,
  • André Luiz Andrade Simões and
  • Julio Cesar de Souza Inácio Gonçalves

Humic substances (HSs) pose a significant challenge to safe drinking-water production due to their ubiquity, limited removal by conventional methods, and their role in forming toxic disinfection by-products, reinforcing the need for more efficient, e...

  • Article
  • Open Access
3 Citations
2,322 Views
22 Pages

The global shift towards cleaner energy has accelerated the application of hydrogen as a clean fuel. Retrofitting and reusing existing natural gas (NG) pipeline infrastructure is a cost-effective way to enable bulk deployment of hydrogen. This study...

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Clean Technol. - ISSN 2571-8797