Editorial

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3 pages, 194 KiB

Open AccessEditorial

Special Issue on the Intensified Conversion of Organic Waste into Biogas

by Gilberto Martins

Appl. Sci. 2022, 12(7), 3573; https://doi.org/10.3390/app12073573 - 31 Mar 2022

Cited by 1 | Viewed by 1135

Abstract

Anaerobic digestion is a sustainable technology used to produce renewable gas from organic wastes [...] Full article

(This article belongs to the Special Issue Intensified Conversion of Organic Waste into Biogas)

Research

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19 pages, 1499 KiB

Open AccessArticle

Biochemical Methane Potential of Cork Boiling Wastewater at Different Inoculum to Substrate Ratios

by Roberta Mota-Panizio, Manuel Jesús Hermoso-Orzáez, Luis Carmo-Calado, Gonçalo Lourinho and Paulo Sérgio Duque de Brito

Appl. Sci. 2021, 11(7), 3064; https://doi.org/10.3390/app11073064 - 30 Mar 2021

Cited by 7 | Viewed by 2084

Abstract

The present study evaluates the digestion of cork boiling wastewater (CBW) through a biochemical methane potential (BMP) test. BMP assays were carried out with a working volume of 600 mL at a constant mesophilic temperature (35 °C). The experiment bottles contained CBW and [...] Read more.

The present study evaluates the digestion of cork boiling wastewater (CBW) through a biochemical methane potential (BMP) test. BMP assays were carried out with a working volume of 600 mL at a constant mesophilic temperature (35 °C). The experiment bottles contained CBW and inoculum (digested sludge from a wastewater treatment plant (WWTP)), with a ratio of inoculum/substrate (Ino/CBW) of 1:1 and 2:1 on the basis of volatile solids (VSs); the codigestion with food waste (FW) had a ratio of 2/0.7:0.3 (Ino/CBW:FW) and the codigestion with cow manure (CM) had a ratio of 2/0.5:0.5 (Ino/CBW:CM). Biogas and methane production was proportional to the inoculum substrate ratio (ISR) used. BMP tests have proved to be valuable for inferring the adequacy of anaerobic digestion to treat wastewater from the cork industry. The results indicate that the biomethane potential of CBWs for Ino/CBW ratios 1:1 and 2:1 is very low compared to other organic substrates. For the codigestion tests, the test with the Ino/CBW:CM ratio of 2/0.7:0.3 showed better biomethane yields, being in the expected values. This demonstrated that it is possible to perform the anaerobic digestion (AD) of CBW using a cosubstrate to increase biogas production and biomethane and to improve the quality of the final digestate. Full article

(This article belongs to the Special Issue Intensified Conversion of Organic Waste into Biogas)

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18 pages, 3839 KiB

Open AccessArticle

Spatially Explicit Model for Anaerobic Co-Digestion Facilities Location and Pre-Dimensioning Considering Spatial Distribution of Resource Supply and Biogas Yield in Northwest Portugal

by Renata D’arc Coura, Joaquim Mamede Alonso, Ana Cristina Rodrigues, Ana Isabel Ferraz, Nuno Mouta, Renato Silva and A. G. Brito

Appl. Sci. 2021, 11(4), 1841; https://doi.org/10.3390/app11041841 - 19 Feb 2021

Cited by 4 | Viewed by 2315

Abstract

The high volumes of animal manure and sewage sludge, as a consequence of the development of intensive and specialized cattle dairy farms in peri-urban areas, pose challenges to local environmental quality and demands for systems innovation. Besides these negative impacts, energy recovery from [...] Read more.

The high volumes of animal manure and sewage sludge, as a consequence of the development of intensive and specialized cattle dairy farms in peri-urban areas, pose challenges to local environmental quality and demands for systems innovation. Besides these negative impacts, energy recovery from biogas produced in anaerobic co-digestion processes should contribute to local sustainable development. This research considers technical data obtained from the optimization of biomethanization processes using sewage sludge and cattle manure liquid fraction, aiming to develop a spatially explicit model including multicriteria evaluation and an analytical hierarchy process to locate biogas production facilities, allocate energy resources and consider biogas unit pre-dimensioning analysis. According to the biophysical conditions and socioeconomic dynamics of the study area (Vila do Conde, Northwest Portugal), a spatially explicit model using multicriteria and multiobjective techniques allowed the definition of suitable locations, as well as the allocation of resources and support pre-dimensioning of biogas facilities. A p-median model allowed us to allocate resources and pre-dimensioning biogas facilities according to distance and accessibility elements. The results indicate: (i) the location of areas with adequate environmental conditions and socioeconomic suitability advantages to install biogas production facilities, and (ii) the ability to compare the options of centralized or distributed location alternatives and associated pre-dimensioning. Full article

(This article belongs to the Special Issue Intensified Conversion of Organic Waste into Biogas)

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28 pages, 2149 KiB

Open AccessFeature PaperArticle

Thermal Hydrolysis of Sewage Sludge: A Case Study of a WWTP in Burgos, Spain

by José García-Cascallana, Xiomar Gómez Barrios and E. Judith Martinez

Appl. Sci. 2021, 11(3), 964; https://doi.org/10.3390/app11030964 - 21 Jan 2021

Cited by 10 | Viewed by 4353

Abstract

An evaluation of the energy and economic performance of thermal hydrolysis technologies is carried out on a theoretical basis. The wastewater treatment plant (WWTP) of Burgos (Spain) was the base scenario of this evaluation. Energy and mass balances were established considering the registered [...] Read more.

An evaluation of the energy and economic performance of thermal hydrolysis technologies is carried out on a theoretical basis. The wastewater treatment plant (WWTP) of Burgos (Spain) was the base scenario of this evaluation. Energy and mass balances were established considering the registered data of primary and secondary thickened sludge in the WWTP for 2011 to 2016. These balances were analysed considering five different scenarios, taking as Scenario 1, the plant operating with conventional mesophilic digestion. The scenarios considered commercially available technologies. The best results were obtained when hydrolysis was applied to digested sludge and sludge from the Solidstream^® process. These two scenarios showed the best performance regarding volatile solid removal and lower demand for live steam, achieving a higher amount of biogas available for valorisation using combined heat and power (CHP) units. The main advantage of the hydrolysis process is the decrease in the volume of digesters and the amount of dewatered sludge needing final disposal. The Solidstream^® process allowed a 35% increase in biogas available for engines and a 23% increase in electricity production. Full article

(This article belongs to the Special Issue Intensified Conversion of Organic Waste into Biogas)

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17 pages, 1745 KiB

Open AccessFeature PaperArticle

The Impact of Antimicrobial Substances on the Methanogenic Community during Methane Fermentation of Sewage Sludge and Cattle Slurry

by Izabela Koniuszewska, Małgorzata Czatzkowska, Monika Harnisz and Ewa Korzeniewska

Appl. Sci. 2021, 11(1), 369; https://doi.org/10.3390/app11010369 - 01 Jan 2021

Cited by 11 | Viewed by 2528

Abstract

This study showed the effect of amoxicillin (AMO), and oxytetracycline (OXY) at a concentration of 512 µg mL⁻¹, and sulfamethoxazole (SMX), and metronidazole (MET) at a concentration of 1024 µg mL⁻¹ on the efficiency of anaerobic digestion (AD) of sewage [...] Read more.

This study showed the effect of amoxicillin (AMO), and oxytetracycline (OXY) at a concentration of 512 µg mL⁻¹, and sulfamethoxazole (SMX), and metronidazole (MET) at a concentration of 1024 µg mL⁻¹ on the efficiency of anaerobic digestion (AD) of sewage sludge (SS) and cattle slurry (CS). The production of biogas and methane (CH₄) content, and the concentration of volatile fatty acids (VFAs) was analyzed in this study. Other determinations included the concentration of the mcrA gene, which catalyzes the methanogenesis, and analysis of MSC and MST gene concentration, characteristic of the families Methanosarcinaceae and Methanosaetaceae (Archaea). Both substrates differed in the composition of microbial communities, and in the sensitivity of these microorganisms to particular antimicrobial substances. Metronidazole inhibited SS fermentation to the greatest extent (sixfold decrease in biogas production and over 50% decrease in the content of CH₄). The lowest concentrations of the mcrA gene (10⁶ g_D⁻¹) were observed in CS and SS digestates with MET. A decline in the number of copies of the MSC and MST genes was noted in most of the digestate samples with antimicrobials supplementation. Due to selective pressure, antimicrobials led to a considerably lowered efficiency of the AD process and induced changes in the structure of methanogenic biodiversity. Full article

(This article belongs to the Special Issue Intensified Conversion of Organic Waste into Biogas)

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13 pages, 2315 KiB

Open AccessFeature PaperArticle

Multi-Walled Carbon Nanotubes Enhance Methanogenesis from Diverse Organic Compounds in Anaerobic Sludge and River Sediments

by Ana J. Cavaleiro, Andreia F. Salvador, Gilberto Martins, Cláudia C. Oliveira, Yuchen Liu, Valdo R. Martins, Ana Rita Castro, Olívia Salomé G. P. Soares, Manuel Fernando R. Pereira, Luciana Pereira, Alette A. M. Langenhoff, Maria Alcina Pereira and M. Madalena Alves

Appl. Sci. 2020, 10(22), 8184; https://doi.org/10.3390/app10228184 - 19 Nov 2020

Cited by 8 | Viewed by 2035

Abstract

Conductive nanomaterials affect anaerobic digestion (AD) processes usually by improving methane production. Nevertheless, their effect on anaerobic communities, and particularly on specific trophic groups such as syntrophic bacteria or methanogens, is not extensively reported. In this work, we evaluate the effect of multi-walled [...] Read more.

Conductive nanomaterials affect anaerobic digestion (AD) processes usually by improving methane production. Nevertheless, their effect on anaerobic communities, and particularly on specific trophic groups such as syntrophic bacteria or methanogens, is not extensively reported. In this work, we evaluate the effect of multi-walled carbon nanotubes (MWCNT) on the activity of two different anaerobic microbial communities: an anaerobic sludge and a river sediment. Methane production by anaerobic sludge was assessed in the presence of different MWCNT concentrations, with direct methanogenic substrates (acetate, hydrogen) and with typical syntrophic substrates (ethanol, butyrate). MWCNT accelerated the initial specific methane production rate (SMPR) from all compounds, with a more pronounced effect on the assays with acetate and butyrate, i.e., 2.1 and 2.6 times, respectively. In the incubations with hydrogen and ethanol, SMPR increased 1.1 and 1.2 times. Experiments with the river sediment were performed in the presence of MWCNT and MWCNT impregnated with 2% iron (MWCNT-Fe). Cumulative methane production was 10.2 and 4.5 times higher in the assays with MWCNT-Fe and MWCNT, respectively, than in the assays without MWCNT. This shows the high potential of MWCNT toward bioenergy production, in waste/wastewater treatment or ex situ bioremediation in anaerobic digesters. Full article

(This article belongs to the Special Issue Intensified Conversion of Organic Waste into Biogas)

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15 pages, 1660 KiB

Open AccessArticle

Biogas Potential of Wastes and By-Products of the Alcoholic Beverage Production Industries in the Spanish Region of Cantabria

by Jesús A. Montes and Carlos Rico

Appl. Sci. 2020, 10(21), 7481; https://doi.org/10.3390/app10217481 - 24 Oct 2020

Cited by 12 | Viewed by 2846

Abstract

The industry of alcoholic beverage production has been, historically, both an important economic engine and a source of wastes and pollution (due to the production processes by themselves and to the energy requirements) in a number of countries. In the small region of [...] Read more.

The industry of alcoholic beverage production has been, historically, both an important economic engine and a source of wastes and pollution (due to the production processes by themselves and to the energy requirements) in a number of countries. In the small region of Cantabria, in northern Spain, the production of alcoholic beverages as an economic sector has been growing in importance in recent years. Thus, there is a new flow of waste for which specific management plans have yet to be developed. The result is an increase in the total amount of urban waste to be disposed. Anaerobic digestion can be a suitable in-situ solution for the treatment of the generated wastes providing a source of renewable energy which can be a supply for the processes in these industries, reducing the emission of greenhouse gases associated to the use of fossil fuels, all of this benefitting both environment and economy. In this work the authors present the information gathered about waste generation and the biomethanogenic potential of the most important wastes generated in the industries. As a result, specific strategies could be designed for the industrial sector in the region, of which other small agro-industries can benefit. Full article

(This article belongs to the Special Issue Intensified Conversion of Organic Waste into Biogas)

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16 pages, 3050 KiB

Open AccessArticle

Thermophilic Methane Production from Hydrothermally Pretreated Norway Spruce (Picea abies)

by Nirmal Ghimire, Rune Bakke and Wenche Hennie Bergland

Appl. Sci. 2020, 10(14), 4989; https://doi.org/10.3390/app10144989 - 20 Jul 2020

Cited by 8 | Viewed by 2006

Abstract

Norway spruce (Picea abies) is an industrially important softwood species available in northern Europe and can be used to produce bio-methane after proper pretreatment to overcome its recalcitrant complex structure. Hot water extraction (HWE) pretreatment at two different conditions (170 °C [...] Read more.

Norway spruce (Picea abies) is an industrially important softwood species available in northern Europe and can be used to produce bio-methane after proper pretreatment to overcome its recalcitrant complex structure. Hot water extraction (HWE) pretreatment at two different conditions (170 °C for 90 min (severity 4.02) and 140 °C for 300 min (severity 3.65)) was applied to extract hemicellulosic sugars from Norway spruce for thermophilic anaerobic digestion (AD) of the hydrolysate. The methane yield of hydrolysate prepared at the lower pretreatment severity was found to be 189 NmL/gCOD compared to 162 NmL/gCOD after the higher pretreatment severity suggesting higher pretreatment severity hampers the methane yield due to the presence of inhibitors formed due to sugars and lignin degradation and soluble lignin, extracted partially along with hemicellulosic sugars. Synthetic hydrolysates simulating real hydrolysates (H170syn and H140syn) had improved methane yield of 285 NmL/gCOD and 295 NmL/gCOD, respectively in the absence of both the inhibitors and soluble lignin. An effect of organic loadings (OLs) on the methane yield was observed with a negative correlation between OL and methane yield. The maximum methane yield was 290 NmL/gCOD for hydrolysate pretreated at 140 °C compared to 195 NmL/gCOD for hydrolyate pretreated at 170 °C, both at the lowest OL of 6 gCOD/L. Therefore, both pretreatment conditions and OL need to be considered for efficient methane production from extracted hydrolysate. Such substrates can be utilized in continuous flow industrial AD with well-adapted cultures with stable organic loading rates. Full article

(This article belongs to the Special Issue Intensified Conversion of Organic Waste into Biogas)

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16 pages, 2105 KiB

Open AccessArticle

Process Simulation of Co-Gasification of Raw Municipal Solid Waste and Bituminous Coal in CO₂/O₂ Atmosphere

by Guangchao Ding and Boshu He

Appl. Sci. 2020, 10(6), 1921; https://doi.org/10.3390/app10061921 - 11 Mar 2020

Cited by 5 | Viewed by 2547

Abstract

An integrated CO₂/O₂ co-gasification system of municipal solid waste (MSW) and bituminous coal (BC) with CO₂ capture was developed and simulated by the Aspen plus, which mainly consisted of three processes: air separation unit, co-gasification system, and CO₂ [...] Read more.

An integrated CO₂/O₂ co-gasification system of municipal solid waste (MSW) and bituminous coal (BC) with CO₂ capture was developed and simulated by the Aspen plus, which mainly consisted of three processes: air separation unit, co-gasification system, and CO₂ absorption unit. In addition, raw syngas composition, cold gas efficiency (CGE), and overall energy efficiency (OEE) of the entail system were evaluated in detail with respect to the main operating parameters (gasification temperature, T; oxygen equivalence ratio, R_o; mole of CO₂ to carbon ratio, R_c; and the MSW blending ratio, R_M). The results indicated that the addition of BC improved the gasification of MSW. Higher gasification temperature increased CGE and OEE. Increasing the R_c ratio led to the decrease of H₂ mole fraction due to the enhanced reverse water-gas shift reaction. In addition, the CGE and OEE of the system decreased with increasing R_M. From the analyses of the parameters, the most optimal operating conditions were set as T = 900 °C, R_o = 0.2, R_c = 0.5, and R_M = 0.6, and the corresponding OEE of the system reached 0.57. The system can achieve a large processing capacity of MSW at the cost of the efficiency loss of this condition. Full article

(This article belongs to the Special Issue Intensified Conversion of Organic Waste into Biogas)

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