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| 2. |
- Carlos-Pinedo, Sandra, et al.
(författare)
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Assessment of a full-scale solid-state anaerobic co-digestion: A multi-component substrate analysis by using ORWARE
- 2022
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Ingår i: Waste Management. - : Elsevier. - 0956-053X .- 1879-2456. ; 146, s. 36-43
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Tidskriftsartikel (refereegranskat)abstract
- Long-term sustainable biogas production requires different raw material alternatives, especially when reducing the most desirable organic substrate, food waste, which has been set as a goal in the 2030 Agenda. In Sweden, horse manure (HM) is generated in large quantities, and due to its physical and chemical characteristics, it has the potential to be used as a raw material to produce biogas through anaerobic digestion (AD). In order to investigate the challenges that HM digestion can impose in terms of methane yield and/or digestate quality, the modified ORganic WAste REsearch (ORWARE) AD model was applied. The aim was to study the effects of different substrates and combinations of these on the AD process during a full-scale solid-state (SS)-AD. In this sense, the model allows for the analysis of the digestion process of multicomponent substrates at the element level. The simulation results suggested that the replacement of green waste (GW) by HM with wood chips as bedding material gave the best improvement in terms of energy turnover; the liquid fraction of the digestate of this mixture of substrates presented the highest concentration in all the nutrients analyzed, specifically in total carbon-biological and phosphorus. The nutrient concentrations in the digestate from the aforementioned scenario are in line with the SPCR120 certification.
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| 3. |
- Carlos-Pinedo, Sandra, et al.
(författare)
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Methane yield from SS-AD : Experiences to learn by a full spectrum analysis at laboratory-, pilot- and full-scale
- 2019
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Ingår i: Biomass and Bioenergy. - : Elsevier. - 0961-9534 .- 1873-2909. ; 127
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Forskningsöversikt (refereegranskat)abstract
- Solid-state anaerobic digestion (SS-AD) takes place when solid content of the substrate is higher than 15%. Some advantages of this technology have been recognized as e.g., less required water added to raw feedstock and consequently minimized digester size and cost, higher volumetric organic loading rates (OLR) that may lead to higher efficiency methane yield and better acceptance of a wide range of feedstocks. However, scientific studies of SS-AD at pilot- and full-scale are very few and difficulties have been reported in operating SS-AD, especially when the system undergoes a scale-up, where methane production is the purpose. As a result, this review gives a summary of scientific studies for SS-AD processes at laboratory-, pilot- and full-scale, where a great diversity of substrate composition, reactor design and operational parameters have been categorized, and their performances in terms of methane yield have been analyzed. This, in turn, helps to identify that factors affecting methane yields at different scales arise mainly from operational conditions as well as the characteristic of feedstocks. This review even contributes to suggest several strategies for improvement of methane yield at full-scale.
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| 4. |
- Carlos-Pinedo, Sandra
(författare)
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Renewable Energy and Nutrient Valorization from Anaerobic Digestion : Resource-Efficient Solutions
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis presents a comprehensive analysis aimed at understanding process performance, methane yield, and key influencing factors within the context of solid-state anaerobic digestion (SS-AD). SS-AD is used to treat organic material with high solids content, which can be challenging to address by alternative methods. The investigation involves modelling and simulation exploring mass and energy balances and the associated environmental implications. To achieve this, a waste management tool, ORganic WAste REsearch (ORWARE) was adapted and validated to suit the unique parameters of SS-AD operating under a plug-flow reactor configuration, representing a specific case study. The search of an optimal feedstock mix that enhances the digestion process and energy performance is highlighted. Findings suggest that feedstock selection significantly affects methane yield in SS-AD systems, and optimizing substrate mixtures can enhance process efficiency. Key considerations include biodegradability and lignocellulosic content. Operational parameters, such as temperature variations, impact the results from the model, while responsiveness of hydraulic retention time and organic loading rate remains limited. A further comparison between a liquid anaerobic digestion (L-AD) vs SS-AD is made, despite similar methane yields, SS-AD outperforms due to higher energy turnover. Additionally, effective management of digestate nutrients is crucial for its biofertilizer use. Beyond the biogas system, the thesis explores interconnected relationships between SS-AD inputs and outputs and their subsequent use as resources for a hydroponic greenhouse production system. The examination of system interconnections and their broader implications emphasizes the importance of comprehensive assessments when integrating biogas systems beyond their conventional applications.
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| 5. |
- Carlos-Pinedo, Sandra, et al.
(författare)
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Study of the digestion process at a full-scale solid-state biogas plant by using ORWARE : Model modification and implementation
- 2020
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Ingår i: Waste Management. - : Elsevier. - 0956-053X .- 1879-2456. ; 107, s. 133-142
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Tidskriftsartikel (refereegranskat)abstract
- The configuration of the reactor influences the digestion process and thus the product yields; other factors such as the rate of biogas production or biogas loss also affect the process specifically with high solid configuration. With these in mind, the ORganic WAste REsearch (ORWARE) anaerobic digestion sub-model was modified to be able to study solid-state anaerobic digestion (SS-AD) (using plug-flow reactor). The simulation results from the updated model agreed with the operational data with respect to methane yield, digestate yield and energy turnover. The model was found to be sensitive to changes in feedstock composition but to a lesser extent to changes in process temperature and retention time. By applying the model on several cases of liquid anaerobic digestion (L-AD), it was noticed that L-AD at mesophilic condition with 25 retention days seemed to be superior to other cases of L-AD with regard to energy turnover. However, even if similar methane production were observed for L-AD and SS-AD, the model suggested higher energy turnover for the case of SS-AD at thermophilic condition, being 10% more in average in comparison with cases of L-AD.
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| 7. |
- Danevad, Daniel, et al.
(författare)
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Exploring Interactions Between Fruit and Vegetable Production in a Greenhouse and an Anaerobic Digestion Plant—Environmental Implications
- 2021
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Ingår i: Frontiers in Sustainability. - : Frontiers. - 2673-4524. ; 2
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Tidskriftsartikel (refereegranskat)abstract
- Greenhouse fruit and vegetable production uses large amounts of energy and other resources, and finding ways of reducing its impact may increase sustainability. Outputs generated from solid-state anaerobic digestion (SS-AD) are suitable for use in greenhouses, which creates a need to investigate the consequences of the possible interactions between them. Connecting the fruit and vegetable production with the resource flows from an SS-AD process, e.g., biogas and digestate, could increase circularity while decreasing the total environmental impact. There are currently no studies where a comprehensive assessment of the material flows between greenhouses and SS-AD are analyzed in combination with evaluation of the environmental impact. In this study, material flow analysis is used to evaluate the effects of adding tomato related waste to the SS-AD, while also using life cycle assessment to study the environmental impact of the system, including production of tomatoes in a greenhouse and the interactions with the SS-AD. The results show that the environmental impact decreases for all evaluated impact categories as compared to a reference greenhouse that used inputs and outputs usually applied in a Swedish context. Using the tomato related waste as a feedstock for SS-AD caused a decrease of biomethane and an increase of carbon dioxide and digestate per ton of treated waste, compared to the digestion of mainly food waste. In conclusion, interactions between a greenhouse and an SS-AD plant can lead to better environmental performance by replacing some of the fertilizer and energy required by the greenhouse.
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