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Wastewater treatment plants (WWTP) located in regions far from a high-pressure grid can produce renewable biomethane, which can partially substitute the natural gas locally consumed. However, the economic viability of implementing biomethane plants in WWTP has to be guaranteed. This paper uses the discount cash flow method to analyze the economic viability of producing biomethane in a WWTP located in Évora (Portugal). The results show that, under the current conditions, it is unprofitable to produce biomethane in this WWTP. Since selling the CO2 separated from biogas may result in an additional income, this option was also considered. In this case, a price of 46 EUR/t CO2 has to be paid to make the project viable. Finally, the impact of potential government incentives in the form of feed-in premia was investigated. Without selling CO2, the project would only be profitable for feed-in premia above 55.5 EUR/MWh. If all the CO2 produced was sold at 30 EUR/t CO2, a premium price of 20 EUR/MWh would make the project profitable. This study shows that the economic attractiveness of producing biomethane in small WWTP is only secured through sufficient financial incentives, which are vital for developing the biomethane market with all its associated advantages.
Francisco Baena-Moreno; Isabel Malico; Isabel Marques. Promoting Sustainability: Wastewater Treatment Plants as a Source of Biomethane in Regions Far from a High-Pressure Grid. A Real Portuguese Case Study. Sustainability 2021, 13, 8933 .
AMA StyleFrancisco Baena-Moreno, Isabel Malico, Isabel Marques. Promoting Sustainability: Wastewater Treatment Plants as a Source of Biomethane in Regions Far from a High-Pressure Grid. A Real Portuguese Case Study. Sustainability. 2021; 13 (16):8933.
Chicago/Turabian StyleFrancisco Baena-Moreno; Isabel Malico; Isabel Marques. 2021. "Promoting Sustainability: Wastewater Treatment Plants as a Source of Biomethane in Regions Far from a High-Pressure Grid. A Real Portuguese Case Study." Sustainability 13, no. 16: 8933.
A hybrid anaerobic reactor was operated under the complementary effluents concept to reduce the unbalanced/inhibitory capacity of the provided piggery effluent. Brewery wastewater was chosen to complement piggery effluent (60:40% v/v, respectively). The HRT reduction from 6.7 to 3.0 days allowed the testing of an organic load increase from 4.5 to 10.0 g COD/L·d, which resulted in the almost doubling of biogas production. Biogas volumes (1.2 and 2.1 L/L·d, respectively) associated with its quality (>77% CH4) revealed that the hybrid anaerobic reactor responded positively to the operational changes and that piggery effluent can be advantageously digested using the brewery wastewater as the complementary effluent. The unit bottom and the packing bed were the main functional sections recognized in the hybrid. At the beginning of anaerobic digestion, bacterial populations belonged mostly to Bacteroidales (33%) and Clostridiales (35%). The process stability and the biogas quality at 3-d HRT were related to a change in the structure composition, since Flavobacteriales (18%), Bacillales (7%), Pseudomonadales (11%) and members of the Alcaligenaceae family (5%) also integrated the microbial communities. An evident change had also occurred in archaeal populations at this phase. Methanosaeta became the dominant genus (95%), confirming that acetoclastic methanogenesis was the main way for methane production.
Ana Eusébio; André Neves; Isabel Marques. Complementary Substrates-Brewery Wastewater and Piggery Effluent—Assessment and Microbial Community Profiling in a Hybrid Anaerobic Reactor. Applied Sciences 2021, 11, 4364 .
AMA StyleAna Eusébio, André Neves, Isabel Marques. Complementary Substrates-Brewery Wastewater and Piggery Effluent—Assessment and Microbial Community Profiling in a Hybrid Anaerobic Reactor. Applied Sciences. 2021; 11 (10):4364.
Chicago/Turabian StyleAna Eusébio; André Neves; Isabel Marques. 2021. "Complementary Substrates-Brewery Wastewater and Piggery Effluent—Assessment and Microbial Community Profiling in a Hybrid Anaerobic Reactor." Applied Sciences 11, no. 10: 4364.
The present case study deals with new pathways in demand for forest residues disposal in the Lafões region (Portugal), since this biomass is presently regarded as a residue and eliminated through open air burning. Different biomass-to-energy conversion systems have a high sustainability value and, thus, the energy potential of the biomass supplied by the forest of Lafões was assessed, using GIS-based methods and assumptions from the literature. The Lafões region produces large amounts of chicken manure from which energy can be recovered through anaerobic digestion. The energy potential held by the effluent of the several classes of the poultry industry of Lafões was assessed, using IPCC 2006 guidelines to estimate their biomass and methane production potential. Furthermore, integrated solutions were pursued. The present challenge is to explore complementarities between effluents for anaerobic digestion to achieve improved energy and waste management system performances. The complementarity between the residues from maritime pine forest management and from broiler production was assessed through bench-scale anaerobic co-digestion assays, leading to increased methane production when compared to those achieved with single substrate anaerobic digestion. This result highlights the interest of further research concerning complementarities between other effluents in the Lafões region.
Ana D’Espiney; Isabel Paula Marques; Helena Maria Pinheiro. Case Study: Pathways from Forest to Energy in a Circular Economy at Lafões. Forest Biomass - From Trees to Energy 2021, 1 .
AMA StyleAna D’Espiney, Isabel Paula Marques, Helena Maria Pinheiro. Case Study: Pathways from Forest to Energy in a Circular Economy at Lafões. Forest Biomass - From Trees to Energy. 2021; ():1.
Chicago/Turabian StyleAna D’Espiney; Isabel Paula Marques; Helena Maria Pinheiro. 2021. "Case Study: Pathways from Forest to Energy in a Circular Economy at Lafões." Forest Biomass - From Trees to Energy , no. : 1.
Olive oil and pig productions are important industries in Portugal that generate large volumes of wastewater with high organic load and toxicity, raising environmental concerns. The principal objective of this study is to energetically valorize these organic effluents—piggery effluent and olive mill wastewater—through the anaerobic digestion to the biogas/methane production, by means of the effluent complementarity concept. Several mixtures of piggery effluent were tested, with an increasing percentage of olive mill wastewater. The best performance was obtained for samples of piggery effluent alone and in admixture with 30% of OMW, which provided the same volume of biogas (0.8 L, 70% CH4), 63/75% COD removal, and 434/489 L CH4/kg SVin, respectively. The validation of the process was assessed by molecular evaluation through Next Generation Sequencing (NGS) of the 16S rRNA gene. The structure of the microbial communities for both samples, throughout the anaerobic process, was characterized by the predominance of bacterial populations belonging to the phylum Firmicutes, mainly Clostridiales, with Bacteroidetes being the subdominant populations. Archaea populations belonging to the genus Methanosarcina became predominant throughout anaerobic digestion, confirming the formation of methane mainly from acetate, in line with the greatest removal of volatile fatty acids (VFAs) in these samples.
Ana Eusébio; André Neves; Isabel Paula Marques. Structure of Microbial Communities When Complementary Effluents Are Anaerobically Digested. Applied Sciences 2021, 11, 1293 .
AMA StyleAna Eusébio, André Neves, Isabel Paula Marques. Structure of Microbial Communities When Complementary Effluents Are Anaerobically Digested. Applied Sciences. 2021; 11 (3):1293.
Chicago/Turabian StyleAna Eusébio; André Neves; Isabel Paula Marques. 2021. "Structure of Microbial Communities When Complementary Effluents Are Anaerobically Digested." Applied Sciences 11, no. 3: 1293.
In addition to energy benefits, anaerobic digestion offers other interesting advantages. The cork industry is of great environmental, economic and social significance in the western Mediterranean region, with Portugal being the world-leading producer and exporter. Cork boiling wastewater (CBW) is a toxic and recalcitrant organic effluent produced by this sector, which constitutes a serious environmental hazard. However, there is no documented research on anaerobic treatment/valorization performed with this effluent. The work presented here was developed with the aim to use the anaerobic digestion process to convert the CBW polluting organic load into an energy carrier gas and valuable molecules for industry. No lag phases were observed and a methane yield of 0.126 to 0.142 m3 kg-1 chemical oxygen demand (COD)added was registered in the mesophilic consortium experiments carried out in batch flasks at 37 ± 1°C. Anaerobic digestion can be advantageously connected to ultrafiltration or electrochemical processes, due to the following: 1) reduction of ellagic acid content and consequent decrease of CBW viscosity; and 2) increase in conductivity after the anaerobic process, avoiding the electrolyte application of the electrochemical process. The improvement of several CBW biochemical features shows that anaerobic digestion may provide additionally useful molecules. The rise in concentration of some of these compounds, belonging to the benzoic acid family (gallic, protocatechuic, vanillic and syringic acids), is responsible for the increase of antiradical activity of the phenolic fraction. Additionally, some enzymatic activity was also observed and while the laccase activity increased in the digested effluent by anaerobiosis, xylanase was formed in the process. The multidisciplinary approach adopted allowed the valorization of CBW in terms of energy and valuable biomolecules. By exploiting the anaerobic digestion process potential, a novel methodology to toxic and recalcitrant cork processing wastewater was developed.
Isabel Paula Marques; Luis Gil; Francesco La Cara. Energetic and biochemical valorization of cork boiling wastewater by anaerobic digestion. Biotechnology for Biofuels 2014, 7, 67 -67.
AMA StyleIsabel Paula Marques, Luis Gil, Francesco La Cara. Energetic and biochemical valorization of cork boiling wastewater by anaerobic digestion. Biotechnology for Biofuels. 2014; 7 (1):67-67.
Chicago/Turabian StyleIsabel Paula Marques; Luis Gil; Francesco La Cara. 2014. "Energetic and biochemical valorization of cork boiling wastewater by anaerobic digestion." Biotechnology for Biofuels 7, no. 1: 67-67.
Olive mill wastewater (OMW) was digested in its original composition (100% v/v) in an anaerobic hybrid. High concentrations (54–55 kg COD m−3), acid pH (5.0) and lack of alkalinity and nitrogen are some OMW adverse characteristics. Loads of 8 kg COD m−3 d−1 provided 3.7–3.8 m3 biogas m−3 d−1 (63–64% CH4) and 81–82% COD removal. An effluent with basic pH (8.1) and high alkalinity was obtained. A good performance was also observed with weekly load shocks (2.7–4.1, 8.4–10.4 kg COD m−3 d−1) by introducing piggery effluent and OMW alternately. Biogas of 3.0–3.4 m3 m−3 d−1 (63–69% CH4) was reached. Developed biomass (350 days) was neither affected by raw OMW nor by organic shocks. Through the effluents complementarity concept, a stable process able of degrading the original OMW alone was obtained. Unlike what is referred, OMW is an energy resource through anaerobiosis without additional expenses to correct it or decrease its concentration/toxicity.
M.A. Sampaio; M.R. Gonçalves; I.P. Marques. Anaerobic digestion challenge of raw olive mill wastewater. Bioresource Technology 2011, 102, 10810 -10818.
AMA StyleM.A. Sampaio, M.R. Gonçalves, I.P. Marques. Anaerobic digestion challenge of raw olive mill wastewater. Bioresource Technology. 2011; 102 (23):10810-10818.
Chicago/Turabian StyleM.A. Sampaio; M.R. Gonçalves; I.P. Marques. 2011. "Anaerobic digestion challenge of raw olive mill wastewater." Bioresource Technology 102, no. 23: 10810-10818.