Energies

Research

19 pages, 622 KiB

Open AccessArticle

Methodology for Calculating the Energy Security Index of the State: Taking into Account Modern Megatrends

by Andriy Stavytskyy, Ganna Kharlamova, Olena Komendant, Jarosław Andrzejczak and Joanna Nakonieczny

Energies 2021, 14(12), 3621; https://doi.org/10.3390/en14123621 - 18 Jun 2021

Cited by 19 | Viewed by 3414

Abstract

Energy issue stays a top priority for the national security of most countries. Despite numerous international forums, large-scale geoeconomic research, international and national projects, and the development of appropriate strategies, the issue of energy security assessment and understanding of its terminology is not [...] Read more.

Energy issue stays a top priority for the national security of most countries. Despite numerous international forums, large-scale geoeconomic research, international and national projects, and the development of appropriate strategies, the issue of energy security assessment and understanding of its terminology is not a universal practice. The presented study has an ambitious goal to develop a methodology that can provide an objective picture of the energy sector on an international scale with cross-country comparisons under the influence of modern megatrends. Based on 29 indicators, according to the World Bank data since 1991, the energy security index is calculated for the set of world states with further analysis of the cluster dynamics of their common trends in energy security. The index showed its objectivity and resistance to existing shocks in geoeconomic dynamics. An important feature of the proposed index is the possibility to compare the energy security index with 1. This value is, in fact, a European average: if a country has an energy security index greater than 1, it means that its energy level is currently better than the European average, and if it is lower than 1, it means that it is inferior to the level of energy security currently achieved on average in Europe. The concept of calculating the index of energy security of the state is based on a unified comparison of all countries, which allows us to move away from the use of signaling approaches and eliminate subjectivity in calculations, as well as provide a basis for dynamic comparison of energy security. The vital aspect of the index is that it takes into account changes in the energy paradigm, the transition to alternative energy sources, and the comprehension of the role of energy efficiency, in particular, of fossil fuels. The study identifies clusters of countries that have consistent similarities in energy security, which can usually be of practical interest in developing energy strategies and understanding the similarity of geoeconomic interests of these states. Thus, this article contributes not only to the development of scientific approaches to the assessment of energy issues, in particular, through the methodological development of a representative index, but also through the presentation of statistically sound results for further effective management decisions at the state level. Full article

(This article belongs to the Special Issue Biowaste Management)

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16 pages, 6856 KiB

Open AccessArticle

Economic Considerations on Nutrient Utilization in Wastewater Management

by Josef Maroušek and Anna Maroušková

Energies 2021, 14(12), 3468; https://doi.org/10.3390/en14123468 - 11 Jun 2021

Cited by 72 | Viewed by 3506

Abstract

There is wide consensus that Spirulina can serve as a tool for wastewater management and simultaneously provide feedstock for biorefining. However, the economic aspects associated with its use remain a significant challenge. Spirulina cultivated in wastewater decreased the concentrations of both ammonia and [...] Read more.

There is wide consensus that Spirulina can serve as a tool for wastewater management and simultaneously provide feedstock for biorefining. However, the economic aspects associated with its use remain a significant challenge. Spirulina cultivated in wastewater decreased the concentrations of both ammonia and nitrate and also served as a biodiesel source. The oil obtained in the feedstock was subjected to transesterification and turned into biodiesel. The biodiesel was subsequently analyzed in a test motor (water-cooled, four-stroke, single-cylinder compression ignition with injection). The tests were conducted at a constant 1500 rpm, and the output power was 3.7 kW. Mixtures of diesel and biodiesel were also enriched with carbon nanotubes (CNTs). The amount of CNTs added to the diesel was 30 mg L⁻¹. The algae and de-oiled biomass were characterized using XRD analysis, and an ultrasonicator was used to mix the CNTs with diesel and spirulina blends. A series of tests were conducted at different load conditions (25%, 50%, 75%, and 100%) for all fuel blends. Test results were compared with a neat diesel engine with a CR of 17.5:1. Among the fuel blends, the B25 reported improved brake thermal efficiency and reduced emissions. The outcomes are a reduction in thermal efficiency of 0.98% and exhaust gas temperature of 1.7%. The addition of Spirulina biodiesel blends had a positive impact on the reduction of greenhouse gas emissions, including reductions of 16.3%, 3.6%, 6.8%, and 12.35% of CO, NO_x, and smoke, respectively. The specific fuel consumption and CO₂ emissions were reduced by 5.2% and 2.8%, respectively, for B25 fuel blends compared to plain diesel and B50. Concerning cost competitiveness, vigorous research on microalgae for the production of biodiesel can cut production costs in the future. Full article

(This article belongs to the Special Issue Biowaste Management)

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15 pages, 330 KiB

Open AccessFeature PaperArticle

Revised Environmental Kuznets Curve for V4 Countries and Baltic States

by Mihaela Simionescu, Adam Wojciechowski, Arkadiusz Tomczyk and Marcin Rabe

Energies 2021, 14(11), 3302; https://doi.org/10.3390/en14113302 - 4 Jun 2021

Cited by 15 | Viewed by 2078

Abstract

Sustainable development can be achieved when economic development does not produce environmental deterioration. In this context, the aim of the paper is to evaluate the effects of economic development on GHG emissions in the Baltic States (Latvia, Letonia, and Lithuania), and in Hungary, [...] Read more.

Sustainable development can be achieved when economic development does not produce environmental deterioration. In this context, the aim of the paper is to evaluate the effects of economic development on GHG emissions in the Baltic States (Latvia, Letonia, and Lithuania), and in Hungary, the Czech Republic, Slovakia, and Poland (the Visegrád Group or V4 countries) in the period of 1996–2019. The study introduces dynamic ARDL panels in the context of the traditional environmental Kuznets curve (EKC) and renewable Kuznets curve (RKC). The results indicated an inverse-N-shaped and a U-shaped pattern. Energy consumption and labour productivity enhanced pollution, while domestic credit to the private sector, as a share of GDP, and renewable energy consumption supported environmental protection. The implications of these results might help these countries to achieve the targets of the European Green Deal related to the reduction of pollution and the attainment of net zero emissions by 2050. However, national regulations should further promote the use of renewable energy sources. Full article

(This article belongs to the Special Issue Biowaste Management)

18 pages, 4352 KiB

Open AccessArticle

Applying Artificial Intelligence to Predict the Composition of Syngas Using Rice Husks: A Comparison of Artificial Neural Networks and Gradient Boosting Regression

by Hung-Ta Wen, Jau-Huai Lu and Mai-Xuan Phuc

Energies 2021, 14(10), 2932; https://doi.org/10.3390/en14102932 - 19 May 2021

Cited by 13 | Viewed by 2543

Abstract

The purpose of this study is to utilize two artificial intelligence (AI) models to predict the syngas composition of a fixed bed updraft gasifier for the gasification of rice husks. Air and steam-air mixtures are the gasifying agents. In the present work, the [...] Read more.

The purpose of this study is to utilize two artificial intelligence (AI) models to predict the syngas composition of a fixed bed updraft gasifier for the gasification of rice husks. Air and steam-air mixtures are the gasifying agents. In the present work, the feeding rate of rice husks is kept constant, while the air and steam flow rates vary in each case. The consideration of various operating conditions provides a clear comparison between air and steam-air gasification. The effects of the reactor temperature, steam-air flow rate, and the ratio of steam to biomass are investigated here. The concentrations of combustible gases such as hydrogen, carbon monoxide, and methane in syngas are increased when using the steam-air mixture. Two AI models, namely artificial neural network (ANN) and gradient boosting regression (GBR), are applied to predict the syngas compositions using the experimental data. A total of 74 sets of data are analyzed. The compositions of five gases (CO, CO₂, H₂, CH₄, and N₂) are predicted by the ANN and GBR models. The coefficients of determination (R²) range from 0.80 to 0.89 for the ANN model, while the value of R² ranges from 0.81 to 0.93 for GBR model. In this study, the GBR model outperforms the ANNs model based on its ensemble technique that uses multiple weak learners. As a result, the GBR model is more convincing in the prediction of syngas composition than the ANN model considered in this research. Full article

(This article belongs to the Special Issue Biowaste Management)

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15 pages, 2446 KiB

Open AccessArticle

Evaluation of Inoculated Waste Biological Stabilization Degree by Olfactometric Methods

by Mirosław Szyłak-Szydłowski

Energies 2021, 14(7), 1835; https://doi.org/10.3390/en14071835 - 25 Mar 2021

Cited by 2 | Viewed by 2134

Abstract

As a result of compounds’ transformation in the waste biostabilization phases, there is an increase in odor nuisance and health problems among people exposed to odorants. Linking the odor concentration to the degree of waste biostabilization may be an important tool for the [...] Read more.

As a result of compounds’ transformation in the waste biostabilization phases, there is an increase in odor nuisance and health problems among people exposed to odorants. Linking the odor concentration to the degree of waste biostabilization may be an important tool for the assessment of individual technological variants of biostabilization. The study aimed to link the odor emissions to the biostabilization degree in individual process variants that differed in the inoculum. The tests were carried out on inoculated windrows on the waste mechanical-bological treatment open site. Odor concentrations were measured during the entire seven-week process of biostabilization (weeks 1–7) and compared with kinetics parameters of organic compounds’ decomposition. The olfactometric tests showed the necessity of using the preparation to reduce the value of odor concentration. Research proved that the decrease of odor concentration values could be useful to indicate the particular phases of biostabilization. Also, the proposed method provides an opportunity to optimize the process concerning the function related to the low degree of odor nuisance of the technologies, including selection of environmentally safe inoculum. This issue has application values that may result in the implementation of new control systems for waste stabilization bioreactors and the evaluation of applied technological solutions. Full article

(This article belongs to the Special Issue Biowaste Management)

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12 pages, 1799 KiB

Open AccessArticle

Hydrogen Dark Fermentation for Degradation of Solid and Liquid Food Waste

by Vira Hovorukha, Olesia Havryliuk, Galina Gladka, Oleksandr Tashyrev, Antonina Kalinichenko, Monika Sporek and Agnieszka Dołhańczuk-Śródka

Energies 2021, 14(7), 1831; https://doi.org/10.3390/en14071831 - 25 Mar 2021

Cited by 24 | Viewed by 3246

Abstract

The constant increase in the amount of food waste accumulating in landfills and discharged into the water reservoirs causes environment pollution and threatens human health. Solid and liquid food wastes include fruit, vegetable, and meat residues, alcohol bard, and sewage from various food [...] Read more.

The constant increase in the amount of food waste accumulating in landfills and discharged into the water reservoirs causes environment pollution and threatens human health. Solid and liquid food wastes include fruit, vegetable, and meat residues, alcohol bard, and sewage from various food enterprises. These products contain high concentrations of biodegradable organic compounds and represent an inexpensive and renewable substrate for the hydrogen fermentation. The goal of the work was to study the efficiency of hydrogen obtaining and decomposition of solid and liquid food waste via fermentation by granular microbial preparation (GMP). The application of GMP improved the efficiency of the dark fermentation of food waste. Hydrogen yields reached 102 L/kg of solid waste and 2.3 L/L of liquid waste. The fermentation resulted in the 91-fold reduction in the weight of the solid waste, while the concentration of organics in the liquid waste decreased 3-fold. Our results demonstrated the potential of granular microbial preparations in the production of hydrogen via dark fermentation. Further development of this technology may help to clean up the environment and reduce the reliance on fossil fuels by generating green hydrogen via recycling of household and industrial organic wastes. Full article

(This article belongs to the Special Issue Biowaste Management)

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14 pages, 1287 KiB

Open AccessArticle

Assessment of Energy Efficiency Gaps: The Case for Ukraine

by Tetyana Vasylieva, Vladyslav Pavlyk, Yuriy Bilan, Grzegorz Mentel and Marcin Rabe

Energies 2021, 14(5), 1323; https://doi.org/10.3390/en14051323 - 1 Mar 2021

Cited by 36 | Viewed by 2965

Abstract

This article substantiates the need to find and implement innovative tools to improve the efficiency of the domestic system for energy sector control. The authors determined that energy policy renewal should consider Ukraine’s commitments to transition to a carbon-neutral economy. The systematization of [...] Read more.

This article substantiates the need to find and implement innovative tools to improve the efficiency of the domestic system for energy sector control. The authors determined that energy policy renewal should consider Ukraine’s commitments to transition to a carbon-neutral economy. The systematization of scientific achievements shows that one of the priority tasks is to minimize the gaps in the energy efficiency of the national economy. It is established that, despite the significant scientific achievements in this area, the scientific community has not adopted a single approach to assessing energy efficiency yet. The purpose of this article is to assess the energy efficiency gaps in the national economy, in order to identify their peak values and the factors causing them, and appropriate mechanisms to minimize them. The energy efficiency gaps are assessed using frontal analysis and Shepard’s energy distance function. Analytical data from the World Bank, the Swiss Institute of Economics, and the International Energy Agency form the information base. The study applied software package Stata 14 for calculation the energy efficiency gaps for Ukraine for 2002–2019. The study applied the Shepard’s function translogarithmic, stochastic frontier analysis for the assessment of energy efficiency gaps. According to the study results, the average level of energy efficiency gaps is 0.12, and their values became the largest in 2009 and 2015. First of all, this is due to the impact of the global financial crisis and the escalation of military–political conflicts. The growing dynamics of the energy efficiency gaps level is due to the excess of the negative effect of increasing exports of primary energy resources and inefficient technologies for their processing over the positive impact of energy-efficient innovation imports. In this case, the government should provide a proactive strategy for creating a positive investment climate, in order to attract additional financial resources for extending green innovations and popularizing the green style and cultivate the energy safety behavior in society. Full article

(This article belongs to the Special Issue Biowaste Management)

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14 pages, 1705 KiB

Open AccessArticle

The Effect of Heat Removal during Thermophilic Phase on Energetic Aspects of Biowaste Composting Process

by Piotr Sołowiej, Patrycja Pochwatka, Agnieszka Wawrzyniak, Krzysztof Łapiński, Andrzej Lewicki and Jacek Dach

Energies 2021, 14(4), 1183; https://doi.org/10.3390/en14041183 - 23 Feb 2021

Cited by 12 | Viewed by 2429

Abstract

Composting is the natural, exothermic process where the huge amount of heat that is created is an issue of organic matter decomposition. However, too high temperature can reduce the microbial activity during the thermophilic composting phase. The aim of this study was to [...] Read more.

Composting is the natural, exothermic process where the huge amount of heat that is created is an issue of organic matter decomposition. However, too high temperature can reduce the microbial activity during the thermophilic composting phase. The aim of this study was to analyze the effect of heat excess removal from composted materials on the process dynamic. The experiment was performed in two parallel bioreactors. One of them was equipped with a heat removal system from the bed of the composted material. Three experiments were carried out with mixtures of different proportions: biological waste, wheat straw, and spent coffee grounds. The content of each option was determined based on a previous study of substrates to maintain the C/N ratio for the right composting process, provide adequate porosity composted material, and enable a proper degree of aeration. The study showed the possibility of receiving part of the heat from the bed of composted material during the thermophilic phase of the process without harm both to the course of composting and the quality of the final product. This shows that at a real scale, it can be possible to recover an important amount of heat from composted materials as a low-temperature heat source. Full article

(This article belongs to the Special Issue Biowaste Management)

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13 pages, 2896 KiB

Open AccessArticle

Biochar for Vertical Greenery Systems

by Michal Kraus, Kateřina Žáková and Jaroslav Žák

Energies 2020, 13(23), 6320; https://doi.org/10.3390/en13236320 - 30 Nov 2020

Cited by 2 | Viewed by 2342

Abstract

Vertical greenery systems (VGS) are effective at solving urban heat. They can absorb noise pollution and dust, and, aesthetically, they are positively perceived. Systems using hydroponic irrigation and nutrition, in combination with mineral wool as a base, are light and effective (they are [...] Read more.

Vertical greenery systems (VGS) are effective at solving urban heat. They can absorb noise pollution and dust, and, aesthetically, they are positively perceived. Systems using hydroponic irrigation and nutrition, in combination with mineral wool as a base, are light and effective (they are able to hold water, with a high percentage of air, and a good mechanical structure to hold the plant stable). However, the functionality of a system can be compromised if the water supply is depleted or the irrigation system fails. This deficiency can be partially remedied if a certain amount of biochar or a suitable organic fertilizer is also a part of the system. The research task consisted of verifying this assumption and determining the effective amount of the biochar. Samples with different amounts of biochar were examined under the same temperature and humidity conditions; extended drying times, additional costs, and safety tank size savings were found. Subsequently, the effective amount of the biochar was determined by the Data Envelopment Analysis (DEA) method. It has been experimentally verified that biochar has a positive effect and prolongs the drying time; the additional costs are almost offset by the benefits. It should be noted that the results are valid for central Europe, and may be modified for different climate and economic zones. Full article

(This article belongs to the Special Issue Biowaste Management)

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14 pages, 4427 KiB

Open AccessArticle

Analysis of the Characteristics of External Walls of Wooden Prefab Cross Laminated Timber

by Jozef Švajlenka, Mária Kozlovská, Miroslav Badida, Marek Moravec, Tibor Dzuro and František Vranay

Energies 2020, 13(22), 5974; https://doi.org/10.3390/en13225974 - 16 Nov 2020

Cited by 5 | Viewed by 2525

Abstract

A balanced combination of heat flows creates suitable conditions for thermal comfort—a factor contributing to the quality of the internal environment of buildings. The presented analysis of selected thermal-technical parameters is up-to-date and suitable for verifying the parameters of building constructions. The research [...] Read more.

A balanced combination of heat flows creates suitable conditions for thermal comfort—a factor contributing to the quality of the internal environment of buildings. The presented analysis of selected thermal-technical parameters is up-to-date and suitable for verifying the parameters of building constructions. The research also applied a methodology for examining the acoustic parameters of structural parts of buildings in laboratory conditions. In this research, selected variant solutions of perimeter walls based on prefab cross laminated timber were investigated in terms of acoustic and thermal-technical properties. The variants structures were investigated in laboratory but also in model conditions. The results of the analyses show significant differences between the theoretical or declared parameters and the values measured in laboratory conditions. The deviations of experimental measurements from the calculated or declared parameters were not as significant for variant B as they were for variant A. These findings show that for these analyzed sandwich structures based on wood, it is not always possible to reliably declare calculated values of thermal-technical and acoustic parameters. It is necessary to thoroughly examine such design variants, which would contribute to the knowledge in this field of research of construction systems based on wood. Full article

(This article belongs to the Special Issue Biowaste Management)

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21 pages, 3852 KiB

Open AccessArticle

Carbon Monoxide Formation during Aerobic Biostabilization of the Organic Fraction of Municipal Solid Waste: The Influence of Technical Parameters in a Full-Scale Treatment System

by Sylwia Stegenta-Dąbrowska, Peter F. Randerson, Sarah R. Christofides and Andrzej Białowiec

Energies 2020, 13(21), 5624; https://doi.org/10.3390/en13215624 - 27 Oct 2020

Cited by 2 | Viewed by 1926

Abstract

The present study sought to investigate the formation of carbon monoxide (CO) during aerobic biostabilization (AB) of the organic fraction of municipal solid waste (OFMSW) in forced aerated piles. Understanding the factors influencing CO formation may be important not only for safety, but [...] Read more.

The present study sought to investigate the formation of carbon monoxide (CO) during aerobic biostabilization (AB) of the organic fraction of municipal solid waste (OFMSW) in forced aerated piles. Understanding the factors influencing CO formation may be important not only for safety, but also for environmental and technical reasons. The objective of the study was to determine the effect of the technical parameters of the piles on the concentration of CO in the process gas during AB of the OFMSW in a full-scale waste treatment system: rate of waste aeration (from 3365 to 12,744 m³∙Mg⁻¹), waste mass loads in the pile (from 391 to 702 Mg), thermal conditions, application of sidewalls as an element of pile bioreactor construction, concentration of O₂ and CO₂ in the waste piles and the duration of the process from 6 to 9 weeks. The temperature and concentration of O₂, CO₂, CO, CH₄ were measured in each pile at weekly intervals. All six reactors provide stable thermal and aerobic conditions, but the presence of CO was observed, ranging from a few to over 2000 ppm, which demonstrated that ensuring optimum conditions for the process is not sufficient for CO to be eliminated. A moderate, non-linear rise in CO concentration was observed along with a rise in the temperature inside the reactors. Concentrations of CO were not highly correlated with those of O₂ or CO₂. An increase in waste mass loads increased the CO concentration in waste piles, while application of sidewalls decreased CO concentration. Increasing aeration rate had an influence on CO production, and the highest CO concentrations were noted under air flow rate 5.3 m³·Mg⁻¹·h⁻¹. Full article

(This article belongs to the Special Issue Biowaste Management)

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22 pages, 5844 KiB

Open AccessArticle

Kinetics of Biotic and Abiotic CO Production during the Initial Phase of Biowaste Composting

by Sylwia Stegenta-Dąbrowska, Karolina Sobieraj, Jacek A. Koziel, Jerzy Bieniek and Andrzej Białowiec

Energies 2020, 13(20), 5451; https://doi.org/10.3390/en13205451 - 19 Oct 2020

Cited by 6 | Viewed by 2380

Abstract

Knowledge of kinetic parameters of CO production during biowaste composting is significantly important for the prediction of its course and estimation of total gas quantity. This allows increasing the control of the process, to minimize its negative impact on the environment and to [...] Read more.

Knowledge of kinetic parameters of CO production during biowaste composting is significantly important for the prediction of its course and estimation of total gas quantity. This allows increasing the control of the process, to minimize its negative impact on the environment and to protect the occupational safety of employees exposed to CO in the biowaste composting plant. For the first time, a full study of the influence of temperature and biowaste sterilization on the kinetics of CO production is presented. The lab-scale experiments used a mixture of green waste, dairy cattle manure, and sawdust in two variants: sterilized and non-sterilized samples. The process was carried out in controlled temperature reactors with measuring the concentrations of CO, O₂, and CO₂ every 12 h.CO production and k value increased with temperature. However, higher CO production was observed in biotic conditions between 10~50 °C, suggesting the biotic CO formation and 1st-order kinetics. The abiotic (thermochemical) process was more efficiently generating CO above 50 °C, described with a 0-order kinetic model. Additionally, the rate constant (k) value of CO production under biotic conditions was increasing up to a temperature of 60 °C, above which a slight decrease in CO production rate was observed at 70 °C. The presented results are the basis for further studies focused on the feasibility of (1) the mitigation and (2) valorization of CO production during the biowaste biostabilization are warranted. Full article

(This article belongs to the Special Issue Biowaste Management)

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13 pages, 1016 KiB

Open AccessArticle

Modified Biochar—A Tool for Wastewater Treatment

by Marek Kopecký, Ladislav Kolář, Petr Konvalina, Otakar Strunecký, Florina Teodorescu, Petr Mráz, Jiří Peterka, Radka Váchalová, Jaroslav Bernas, Petr Bartoš, Feodor Filipov and Daniel Bucur

Energies 2020, 13(20), 5270; https://doi.org/10.3390/en13205270 - 11 Oct 2020

Cited by 20 | Viewed by 3485

Abstract

Global deposits of concentrated phosphates, which are a necessary source for the production of phosphate fertilizers, are limited. These reserves keep getting thinner, and every day, large amounts of phosphorus end up in watercourses. In this study, we verified that modified biochar (saturated [...] Read more.

Global deposits of concentrated phosphates, which are a necessary source for the production of phosphate fertilizers, are limited. These reserves keep getting thinner, and every day, large amounts of phosphorus end up in watercourses. In this study, we verified that modified biochar (saturated with FeCl₃ solution and then neutralized with NaOH solution) can adsorb significant amounts of phosphorus from wastewater. Moreover, the agrochemical qualities of sludge water from a municipal wastewater treatment plant, struvite, phosphorus-saturated biochar, and iron(III) phosphate from a reused biochar filter were tested in this study. We determined the amount of mobile phosphorus as well as the amount of extractable phosphorus and its five fractions. It was found that modified biochar can hold one-third of the phosphorus amount contained in the commonly used agricultural fertilizer simple superphosphate (1 × 10⁵ g of modified biochar captures up to 2.79 × 10³ g of P). Moreover, plants can more easily access phosphorus biochar fractions than struvite, which is formed spontaneously during sludge management. The results of this research prove that the proposed method of recycling phosphorus from wastewater can be applied in technological practice. Full article

(This article belongs to the Special Issue Biowaste Management)

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12 pages, 627 KiB

Open AccessArticle

Techno-Economic Assessment: Food Emulsion Waste Management

by George Lazaroiu, Katarina Valaskova, Elvira Nica, Pavol Durana, Pavol Kral, Petr Bartoš and Anna Maroušková

Energies 2020, 13(18), 4922; https://doi.org/10.3390/en13184922 - 19 Sep 2020

Cited by 41 | Viewed by 2765

Abstract

Production of food-grade emulsions is continuously rising globally, especially in developing countries. The steepest demand growth is in the segment of inexpensive meat products where edible emulsions serve as lubricants to mitigate economic loses linked with mechanical damage during automated processing of artificial [...] Read more.

Production of food-grade emulsions is continuously rising globally, especially in developing countries. The steepest demand growth is in the segment of inexpensive meat products where edible emulsions serve as lubricants to mitigate economic loses linked with mechanical damage during automated processing of artificial casings. Provided that production goal is to minimize emulsion transfer into the product, its vast majority becomes voluminous greasy and sticky waste. Public sewage treatment plants cannot process such waste, its cleaning processes tends to collapse under loads of emulsions. To make matters worse, composition of emulsions often changes (according to actual pricing of main components) and emulsion manufacturers carefully guard their recipes. Therefore, running of in-house sewage plants would require continuous experimentation linked with need for skilled personnel, frequent changes in technology setup and high operating costs in general. Consequently, it was repeatedly and independently reported that emulsion waste is poured onto wildlife, resulting in environmental damage and an intense rotting odor. Three new methods of emulsion breakdown are proposed and techno-economically assessed. High versatility of methods was confirmed and multiple austerity measures were incorporated. Emulsions are also assessed in terms of an energy source for aerobic and anaerobic microorganisms. It is reported that the addition of edible emulsion to compost does not result in increased product quality or cost reduction. It is firstly revealed that edible emulsions can instantly create an anaerobic environment and accelerate biogas production through the formation of surface films on feedstock surface. Adding waste food-grade emulsions to the biogas plant makes it possible to 100% reduce process water consumption in biogas stations as the process speed can be shortened by approximately 12%. Full article

(This article belongs to the Special Issue Biowaste Management)

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16 pages, 1248 KiB

Open AccessArticle

Analysis of the Energy Balance of Constructions Based on Wood during Their Use in Connection with CO₂ Emissions

by Jozef Švajlenka and Mária Kozlovská

Energies 2020, 13(18), 4843; https://doi.org/10.3390/en13184843 - 16 Sep 2020

Cited by 5 | Viewed by 2376

Abstract

In the construction industry, it is the material production phase and the use phase of buildings’ life cycles that represent the greatest environmental burden. The presented research focused on wood constructions during their use phase. The primary objective of the research was to [...] Read more.

In the construction industry, it is the material production phase and the use phase of buildings’ life cycles that represent the greatest environmental burden. The presented research focused on wood constructions during their use phase. The primary objective of the research was to determine the amount of CO₂ produced during the operation of specific wood constructions in connection with the energy demand for their heating. A correlation analysis of selected parameters revealed a statistically significant correlation between heating medium type and energy demand for heating (p = −0.5773) and between heating medium type and amount of CO₂ produced (p = 0.4796). A more detailed analysis showed that, in terms of the average energy demand for heating, the column constructions were the most efficient among the compared construction systems, regardless of the energy standard. Similar findings were obtained for annual CO₂ production in connection with the average energy demand for heating. The only difference was that the panel and log constructions exhibited almost identical parameters, which came as a surprise to some extent. The column constructions turned out to be the most efficient again, regardless of their energy standard. The analysis that focused on the heating medium type revealed statistically significant differences among the heating medium types in energy demand for heating (p < 0.0001). The constructions that used electricity for heating were the most energy-efficient. When the individual characteristics of the different heating media in relation to CO₂ production were taken into account, the constructions that were heated using biomass were the least polluting. The constructions heated using electricity and gas showed a significantly greater deviation. Full article

(This article belongs to the Special Issue Biowaste Management)

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20 pages, 4233 KiB

Open AccessArticle

The Circular Economy and Organic Fraction of Municipal Solid Waste Recycling Strategies

by Anna Rolewicz-Kalińska, Krystyna Lelicińska-Serafin and Piotr Manczarski

Energies 2020, 13(17), 4366; https://doi.org/10.3390/en13174366 - 24 Aug 2020

Cited by 40 | Viewed by 5901

Abstract

Densely populated areas with large incoming populations have difficulty achieving high separate collection rates of municipal solid waste. The manuscript analyzes the link between biowaste collection and circular economy requirements as a fulfilment of the recycling rates and using biogas as a sustainable [...] Read more.

Densely populated areas with large incoming populations have difficulty achieving high separate collection rates of municipal solid waste. The manuscript analyzes the link between biowaste collection and circular economy requirements as a fulfilment of the recycling rates and using biogas as a sustainable energy source. Three biowaste collection scenarios and three technical scenarios for its treatment are considered. The first scenario assumes only composting for biowaste treatment, the next includes also anaerobic digestion. In the years 2020–2050, the separate biowaste collection level will increase, depending on the scenario, from 26.9 kg/inh. up to 148.1kg/inh. By 2030, the quantity of biogas generated from biowaste can grow to almost 9 million m³/year, enabling the production of renewable energy at annual levels of almost 17 GWh and 69 TJ. Using the third scenario, the quantity of biogas generated grows more than twice (in 2035). If the capture rate of biowaste increases from 15% to 20% and then to 25%, the quantity of biogas generated grows by, respectively, 65% and more than 100%. Unfortunately, none of the scenarios enables the required municipal solid waste recycling rates in 2030 (60%) and 2035 (65%), which demonstrates the significant need to develop more effective separate collection systems, including biowaste. Methodology applied in the paper can be used for other cities and regions trying to meet circular economy demands. Full article

(This article belongs to the Special Issue Biowaste Management)

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15 pages, 1690 KiB

Open AccessArticle

Comparison of Laboratory and Computational Models of Selected Thermal-Technical Properties of Constructions Systems Based on Wood

by Jozef Švajlenka, Mária Kozlovská, František Vranay, Terézia Pošiváková and Miroslava Jámborová

Energies 2020, 13(12), 3127; https://doi.org/10.3390/en13123127 - 16 Jun 2020

Cited by 5 | Viewed by 2951

Abstract

Energy-efficient buildings, sustainable buildings, smart buildings, nearly zero-energy buildings, passive and active buildings are construction concepts widely recognised as setting the latest trends. The purpose of their design is to create an optimal thermal microclimate by means of heat flows that are either [...] Read more.

Energy-efficient buildings, sustainable buildings, smart buildings, nearly zero-energy buildings, passive and active buildings are construction concepts widely recognised as setting the latest trends. The purpose of their design is to create an optimal thermal microclimate by means of heat flows that are either formed within it or enter into it. This research paper presents an analysis of the measurements of the density of heat flows, their spread in building constructions, all of which is examined in laboratory conditions and confronted with calculation models. The hypothesis of this research is to confirm or refute whether the computational models match the laboratory simulations in terms of thermal-technical parameters. The research uses a methodology designed for examining building constructions under virtually stable conditions. Two variants of external sandwich walls based on prefab cross laminated timber panels (variant A) and structural insulated panel (variant B) were proposed as the subject of the study. Both variants were subjected to research in laboratory conditions and computational simulations. For the sake of comparison, the calculation simulations that manufacturers of wood construction systems typically declare were also performed. The results of the analyses show significant differences between the theoretical or declared parameters and the values measured in laboratory conditions (7.5–32.6%). The deviations of the experimental measurements from the calculated or declared parameters were not as significant for variant A as they were for variant B. These findings show that for these analysed sandwich structures based on wood, it is not always possible to reliably declare calculated values of thermal-technical parameters. The publication is also a contribution to the current needs in the field of heating technology in terms of sustainability and the quality of internal environments. Full article

(This article belongs to the Special Issue Biowaste Management)

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