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17 pages, 2397 KiB

Open AccessArticle

Sustainable Antioxidant Production for Hygienic Disinfection Using Bioextractants from Lavender and Oregano Distillation Process

by Aikaterini Itziou, Konstantinos Zaralis, Annita Theofanous, Maria Louloudi, Georgios Rozos, Ioanna A. Vasiliadou, Evangelia Lakioti, Vayos Karayannis and Constantinos Tsanaktsidis

Energies 2023, 16(22), 7534; https://doi.org/10.3390/en16227534 - 12 Nov 2023

Viewed by 1171

Abstract

In the current study, the production of novel antioxidants for hygienic disinfection against common pathogenic bacteria, based on the incorporation of bioextractant oils/waters from either lavender or oregano distillates is proposed in the framework of circular economy. For the first time, the main [...] Read more.

In the current study, the production of novel antioxidants for hygienic disinfection against common pathogenic bacteria, based on the incorporation of bioextractant oils/waters from either lavender or oregano distillates is proposed in the framework of circular economy. For the first time, the main compounds found in distillation products (oils/waters), specifically of lavender Lavandula angustifolia (lynalyl acetate and linalool) and of oregano Oreganum vulgare (carvacrol, thymol, and p-cymene) are presented. The analyses of both the lavender and oregano essential oils/waters indicate excellent physicochemical properties and microbial absence. Moreover, the antioxidant activity of all distillates as DPPH radical scavengers is assessed. The results confirm that the essential oils of both oregano and lavender possess superior antioxidant activity to their corresponding waters, while the oregano oil exhibited far better antioxidant activity than the lavender oil, as 1 mL of oregano oil was able to consume 45 μmoles of DPPH radicals. Overall, our research findings suggest that the particular lavender and oregano bioextractants produced possess important potential to address the resistance of bacteria from the perspective of their wider exploitation in therapeutic or preventive medicine, thus contributing to enhancing public health. Full article

(This article belongs to the Special Issue Residual Resource Recovery for Bioenergy and Biomolecule Production in a Circular Economy: Sustainable Process Design and Technoeconomic Feasibility)

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22 pages, 2555 KiB

Open AccessArticle

Aspen Plus^® Process Simulation Model of the Biomass Ash-Based Treatment of Anaerobic Digestate for Production of Fertilizer and Upgradation of Biogas

by Alejandro Moure Abelenda, Abdikhani Ali, Kirk T. Semple and Farid Aiouache

Energies 2023, 16(7), 3039; https://doi.org/10.3390/en16073039 - 27 Mar 2023

Cited by 4 | Viewed by 3876

Abstract

The use of the commercial simulator Aspen Plus^® could bring an amelioration in the accuracy of the predictions of the chemical species composition in the output streams of the anaerobic digestion process. Compared to the traditionally employed lumped models, which are elaborated [...] Read more.

The use of the commercial simulator Aspen Plus^® could bring an amelioration in the accuracy of the predictions of the chemical species composition in the output streams of the anaerobic digestion process. Compared to the traditionally employed lumped models, which are elaborated from scratch, the models implemented in Aspen Plus^® have access to a broad library of thermodynamic and phenomena transport properties. In the present investigation, a process simulation model for anaerobic digestion has been prepared by including a stoichiometric-equilibria reactor to calculate the extent of the ionization of the molecules present in the anaerobic digestate. The model characterizes the technical feasibility of anaerobic digestate stabilization, by means of biomass ash-based treatment, for the production of an organic fertilizer and potential biogas upgradation with the synthesis of ammonium carbonate. First of all, the titration of the manure digestate with the hydrochloric acid showed that a dose of 3.18 mEq/g would be required to attain the targeted pH of zero-point charge, upon addition of the sewage sludge ash in a ratio to the manure digestate of 0.6 ± 0.2%. Secondly, the profiles of ammonia, carbon dioxide, and methane found in the biogas agree with the pH of the treated digestate and enable the upgrading of the biogas with the production of NH₄HCO₃. The model needs to be further developed to ensure the standards are attained in all output streams of stabilized anaerobic digestate, biomethane, and isolated added-value chemical fertilizers. Full article

(This article belongs to the Special Issue Residual Resource Recovery for Bioenergy and Biomolecule Production in a Circular Economy: Sustainable Process Design and Technoeconomic Feasibility)

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14 pages, 2125 KiB

Open AccessArticle

Multi-Criteria Analysis of the Influence of Lignocellulosic Biomass Pretreatment Techniques on Methane Production

by Magdalena Zdeb, Marta Bis and Artur Przywara

Energies 2023, 16(1), 468; https://doi.org/10.3390/en16010468 - 1 Jan 2023

Cited by 2 | Viewed by 1478

Abstract

Methane from environmentally friendly anaerobic digestion may be an alternative non-renewable source that is depleting. One of the substrates for that process may be lignocellulose-based materials. The article concerns comparing the environmental impact as well as technical and energy indicators of alternative ways [...] Read more.

Methane from environmentally friendly anaerobic digestion may be an alternative non-renewable source that is depleting. One of the substrates for that process may be lignocellulose-based materials. The article concerns comparing the environmental impact as well as technical and energy indicators of alternative ways of producing methane from the anaerobic digestion of Pennisetum hybrid. Five scenarios were analyzed: methane production from the anaerobic digestion of the raw grass, the grass subjected to alkaline pretreatment (with 2% NaOH solution at two temperatures), and the grass subjected to mechanical pretreatment (ground to obtain particle sizes <0.18 mm and 0.25–0.38 mm). Multi-criteria decision (MCA) analysis was carried out with the use of five indicators, including life cycle assessment results as well as methane production parameters, in order to optimize this sustainable way of bioenergy production. The purpose of this study was to identify the most cost-effective and environmentally friendly method of Pennisetum hybrid pretreatment in order to optimize the methane production process in terms of environmental, technical, and economic aspects. According to the obtained results, it was stated that the most advantageous solution for the majority of the analyzed indicators turned out to be the mechanical pretreatment with grinding the lignocellulosic biomass into a particle size <0.18 mm. Full article

(This article belongs to the Special Issue Residual Resource Recovery for Bioenergy and Biomolecule Production in a Circular Economy: Sustainable Process Design and Technoeconomic Feasibility)

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13 pages, 1415 KiB

Open AccessArticle

Polyhydroxybutyrate-Natural Fiber Reinforcement Biocomposite Production and Their Biological Recyclability through Anaerobic Digestion

by Danh H. Vu, Amir Mahboubi, Jorge A. Ferreira, Mohammad J. Taherzadeh and Dan Åkesson

Energies 2022, 15(23), 8934; https://doi.org/10.3390/en15238934 - 25 Nov 2022

Cited by 1 | Viewed by 1981

Abstract

The existing recycling methods of PHA-based material are ineffective in terms of increasing resource efficiency and the production of high value end-of-life products. Therefore, in this study, a novel approach of acidogenic fermentation was proposed to recycle PHB-based composites reinforced with natural fibers [...] Read more.

The existing recycling methods of PHA-based material are ineffective in terms of increasing resource efficiency and the production of high value end-of-life products. Therefore, in this study, a novel approach of acidogenic fermentation was proposed to recycle PHB-based composites reinforced with natural fibers such as cellulose, chitin, chitosan, orange waste, sawdust, soy protein, and starch. The inclusion of cellulose, chitosan, and sawdust improved the impact properties of the composites while other fillers had various effects on the mechanical properties. These three composites and neat PHB were subsequently subjected to biological degradation via acidogenic digestion to determine the possibility of converting PHB-based composites into volatile fatty acids (VFAs). Two different pH levels of 6 and 10 were applied to assess the effect of pH on the bioconversion and inhibition of the methanogenesis. The results showed promising PHB degradation, contributing to considerable VFA production of 2.5 g/L at pH 6 after 47 days. At pH 6, the presence of the natural fibers in the biocomposites promoted the degradation rate. On the contrary, pH 10 proved to be more suitable for the degradation of the fibers. The VFA which is produced can be recirculated into PHB production, fitting with the concept of a circulating bioeconomy. Full article

(This article belongs to the Special Issue Residual Resource Recovery for Bioenergy and Biomolecule Production in a Circular Economy: Sustainable Process Design and Technoeconomic Feasibility)

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18 pages, 4809 KiB

Open AccessArticle

Techno-Economic Assessment of Biological Biogas Upgrading Based on Danish Biogas Plants

by Néméhie Lawson, Merlin Alvarado-Morales, Panagiotis Tsapekos and Irini Angelidaki

Energies 2021, 14(24), 8252; https://doi.org/10.3390/en14248252 - 8 Dec 2021

Cited by 25 | Viewed by 4653

Abstract

Biological biogas upgrading with H₂ derived from excess renewable electricity was modeled and simulated in PROII^® (AVEVA Group plc, Cambridge, UK). An economic analysis was performed for a biogas plant processing 100,000 tons of biomass (substrate) per year. The biogas and [...] Read more.

Biological biogas upgrading with H₂ derived from excess renewable electricity was modeled and simulated in PROII^® (AVEVA Group plc, Cambridge, UK). An economic analysis was performed for a biogas plant processing 100,000 tons of biomass (substrate) per year. The biogas and biomethane production simulation results were validated with laboratory experimental data, as well as full-scale data obtained from biogas plants. A biomethane production cost of 0.47 €/Nm³ was calculated, while the minimum biomethane selling price for NPV = 0 was equal to 0.66 €/Nm³, considering a H₂ price of 1.0 €/kg. The feasibility analysis indicated that the H₂-related costs were the major contributor to the capital and operation costs due to high expenses associated with the in-situ H₂ storage facility and the purchasing of H₂, respectively. Compared to conventional upgrading methods, biological biogas upgrading has a higher capital and production cost, which can be reduced by increasing the plant capacity. The sensitivity analysis showed that the profitability is very sensitive to biomethane prices, capital investment, and the H₂ price. Full article

(This article belongs to the Special Issue Residual Resource Recovery for Bioenergy and Biomolecule Production in a Circular Economy: Sustainable Process Design and Technoeconomic Feasibility)

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16 pages, 3667 KiB

Open AccessArticle

Exploitation of Liquid Digestate as the Sole Nutrient Source for Floating Hydroponic Cultivation of Baby Lettuce (Lactuca sativa) in Greenhouses

by Georgios K. Ntinas, Filippos Bantis, Athanasios Koukounaras and Panagiotis G. Kougias

Energies 2021, 14(21), 7199; https://doi.org/10.3390/en14217199 - 2 Nov 2021

Cited by 10 | Viewed by 2752

Abstract

Sustainable agriculture relies on replacing fossil-based mineral fertilizers, which are highly cost-energetic to produce, and demand extensive use of scarce natural resources. Today, agronomic practices within the concept of circular economy are emerging and, as such, the exploitation of digestate as a biofertilizer [...] Read more.

Sustainable agriculture relies on replacing fossil-based mineral fertilizers, which are highly cost-energetic to produce, and demand extensive use of scarce natural resources. Today, agronomic practices within the concept of circular economy are emerging and, as such, the exploitation of digestate as a biofertilizer and soil amender is extensively investigated. This study aimed at evaluating the agronomic potential of liquid digestate as the sole nutrient source for hydroponic cultivation of baby lettuce in greenhouses. Growth rate, physiological responses, concentration of secondary metabolites, and nutrient uptake were compared between baby leaf lettuce grown in digestate in concentrations of 5, 10, and 20% diluted in water (either with or without pH adjustment) and in Hoagland solution (control). Results showed that the production yield was negatively correlated with the concentration of the added digestate. Nevertheless, the antioxidant capacity was significantly enhanced in 5 and 10% liquid digestate treatments compared to the control. Additionally, the nutrient composition in the baby leaf lettuce and the reduction in nutrient concentrations in the growth media demonstrated efficient mineral uptake by the plants. Thus, the application of liquid digestate as a fertilizer in hydroponic systems is a promising practice to recover residual resources, leading to the transition towards more sustainable greenhouse production. Full article

(This article belongs to the Special Issue Residual Resource Recovery for Bioenergy and Biomolecule Production in a Circular Economy: Sustainable Process Design and Technoeconomic Feasibility)

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41 pages, 11315 KiB

Open AccessArticle

Biogas Produced by Anaerobic Digestion Process and Biodiesel from Date Seeds

by Alla Mohammed Alrefai, Raid Alrefai, Khaled Y. Benyounis and Joseph Stokes

Energies 2021, 14(16), 4851; https://doi.org/10.3390/en14164851 - 9 Aug 2021

Cited by 2 | Viewed by 2544

Abstract

Dates are an important food source in many countries that produce different types of dates. Dates have a significant amount of waste, either from planting or eating them. A large amount of seeds are produced from eating it. This study is considered to [...] Read more.

Dates are an important food source in many countries that produce different types of dates. Dates have a significant amount of waste, either from planting or eating them. A large amount of seeds are produced from eating it. This study is considered to explore the quantity and the quality of biogas produced from the Sagai date seeds through the anaerobic digestion process (AD) before and after oil extraction and exploitation of oil in biodiesel production. In addition, the study aims to tests the resulted digestate from the AD process. This test was performed to ensure that the digestate contains the three basics elements (N, P and K) to be used in agriculture. In its preparation, the date seeds were ground after washing via a grinding machine without exposure to any other treatment process. Design of Experiments (DOE) was applied in determining the effect of temperature, volatile solid and sludge quantity on the resulted biogas. The energy balance at the optimum results was calculated. The highest biogas volumes from the AD of date seed before and after oil extraction were 4140 cc and 3534 cc, respectively, at 37 °C, 4.2 g-VS and 50% sludge quantity. While the highest methane/g-VS were 1143.8 cc/g-VS and 949.6 cc/g-VS, respectively, at 37 °C, 1.1 g-VS and 50% sludge quantity. The oil obtained using the Soxhlet method at 70 °C, 1:4 ratio of date seeds to n-hexane solvent and 5 h reaction time was 16% of the date seed mass (79% biodiesel and 9% glycerine). Therefore, the resultant effect from the main findings indicated that the study supports the investigation of the possibility of exploiting date seeds in the production of biogas, biodiesel and bio-fertiliser. Full article

(This article belongs to the Special Issue Residual Resource Recovery for Bioenergy and Biomolecule Production in a Circular Economy: Sustainable Process Design and Technoeconomic Feasibility)

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Review

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14 pages, 3027 KiB

Open AccessReview

Managing the Effluents of Anaerobic Fermentations by Bioprocess Schemes Involving Membrane Bioreactors and Bio-Electrochemical Systems: A Mini-Review

by Gábor Z. Szelényi, Róbert Kurdi, Nándor Nemestóthy, Katalin Bélafi-Bakó and Péter Bakonyi

Energies 2022, 15(5), 1643; https://doi.org/10.3390/en15051643 - 23 Feb 2022

Cited by 1 | Viewed by 2163

Abstract

Anaerobic bioprocesses, such as anaerobic digestion and dark fermentation, provide energy carriers in the form of methane and hydrogen gases, respectively. However, their wastewater-type residues, that is, the fermentation effluents, must be treated carefully due to the incomplete and non-selective conversion of organic [...] Read more.

Anaerobic bioprocesses, such as anaerobic digestion and dark fermentation, provide energy carriers in the form of methane and hydrogen gases, respectively. However, their wastewater-type residues, that is, the fermentation effluents, must be treated carefully due to the incomplete and non-selective conversion of organic matter fed to the actual system. For these reasons, the effluents contain various secondary metabolites and unutilized substrate, in most cases. Only a fraction of anaerobic effluents can be directly applied for fertilization under a moderate climate. Conventional wastewater treatment technologies may be used to clean the remainder, but that approach leads to a net loss of energy and of potentially useful agricultural input materials (organic carbon and NPK fertilizer substitutes). The rationale of this paper is to provide an overview of promising new research results in anaerobic effluent management strategies as a part of technological downstream that could fit the concept of new-generation biorefinery schemes aiming towards zero-waste discharge, while keeping in mind environmental protection, as well as economical perspectives. According to the literature, the effluents of the two above processes can be treated and valorized relying either on membrane bioreactors (in case of anaerobic digestion) or bio-electrochemical apparatus (for dark fermentation). In this work, relevant findings in the literature will be reviewed and analyzed to demonstrate the possibilities, challenges, and useful technical suggestions for realizing enhanced anaerobic effluent management. Both membrane technology and bio-electrochemical systems have the potential to improve the quality of anaerobic effluents, either separately or in combination as an integrated system. Full article

(This article belongs to the Special Issue Residual Resource Recovery for Bioenergy and Biomolecule Production in a Circular Economy: Sustainable Process Design and Technoeconomic Feasibility)

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