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The recovery and utilisation of industrial excess heat has been identified as an important contribution for energy efficiency by reducing primary energy demand. Previous works, based on top-down studies for a few sectors, or regional case studies estimated the overall availability of industrial excess heat. A more detailed analysis is required to allow the estimation of potentials for specific heat recovery technologies, particularly regarding excess heat temperature profiles. This work combines process integration methods and regression analysis to obtain cogeneration targets, detailed excess heat temperature profiles and estimations of electricity generation potentials from low and medium temperature excess heat. The work is based on the use of excess heat temperature (XHT) signatures for individual sites and regression analysis using publicly available data, obtaining estimations of the technical potential for electricity generation from low and medium temperature excess heat (60–140 °C) for the whole Swedish kraft pulp and paper industry. The results show a technical potential to increase the electricity production at kraft mills in Sweden by 10 to 13%, depending on the level of process integration considered, and a lower availability of excess heat than previously estimated in studies for the sector. The approach used could be adapted and applied in other sectors and regions, increasing the level of detail at which industrial excess heat estimations are obtained when compared to previous studies.

The recovery and utilisation of industrial excess heat has been identified as an important contribution for energy efficiency by reducing primary energy demand. Previous works, based on top-down studies for a few sectors, or regional case studies estimated the overall availability of industrial excess heat. A more detailed analysis is required to allow the estimation of potentials for specific heat recovery technologies, particularly regarding excess heat temperature profiles. This work combines process integration methods and regression analysis to obtain cogeneration targets, detailed excess heat temperature profiles and estimations of electricity generation potentials from low and medium temperature excess heat. The work is based on the use of excess heat temperature (XHT) signatures for individual sites and regression analysis using publicly available data, obtaining estimations of the technical potential for electricity generation from low and medium temperature excess heat (60-140 degrees C) for the whole Swedish kraft pulp and paper industry. The results show a technical potential to increase the electricity production at kraft mills in Sweden by 10 to 13%, depending on the level of process integration considered, and a lower availability of excess heat than previously estimated in studies for the sector. The approach used could be adapted and applied in other sectors and regions, increasing the level of detail at which industrial excess heat estimations are obtained when compared to previous studies.

We propose a paper solar cell based on carbon nanotube (CNT)-composite papers. To fabricate this cell, we use dye-sensitized solar cells (DSCs) for generating power through the redox reaction of dyes in conjunction with CNT-composite papers, which are composite materials containing CNTs and pulp (raw paper material) that can be fabricated easily by using a method based on the Japanese washi papermaking technique. The demand for CNT applications is expected to increase due to their high conductivity and metallic or semiconducting characteristics. This CNT-composite paper can also have metallic or semiconducting characteristics based on the contained CNTs in the composite paper. We previously fabricated a DSC that generates electricity by using CNT-composite papers stacked in a typical DSC structure. However, the conversion efficiency of this DSC was just 0.188%, which is not practical. To overcome this low power generation issue, we tried improving the DSC structure by applying electrodes to the CNT-composite papers in grid patterns for efficient current collection and applying an optimally mixed dye for efficient electron excitation. Results showed that the conversion efficiency improved to 0.58%. Moreover, we demonstrated that using a mixed dye can improve the conversion efficiency of the paper DSC. We expect these types of CNT-composite papers to be used as material for new DSCs.

We use origami to create a compact, scalable three-dimensional (3-D) biobattery stack that delivers on-demand energy to the portable biosensors. Folding allows a two-dimensional (2-D) paper sheet possessing predefined functional components to form nine 3-D microbial fuel cells (MFCs), and connect them serially within a small and single unit (5.6 cm × 5.6 cm). We load the biocatalyst Pseudomonas aeruginosa PAO1 in predefined areas that form the MFCs, and freeze-dry them for long-term storage. The biobattery stack generates a maximum power and current of 20 μW and 25 μA, respectively, via microbial metabolism when the freeze-dried cells are rehydrated with readily available wastewater. This work establishes an innovative strategy to revolutionize the fabrication, storage, operation, and application of paper-based MFCs, which could potentially make energy available even in resource-limited settings.

This paper introduces a novel enzymatic fuel cell design that employs cellulose paper-based quasi-2D microfluidic system to supply biofuel to the enzymatic layer. The state of the art nanoarchitectural design, employing carbon nanotube-based papers for the bioelectrodes, allows a single cell to maintain 400 mV for 16 days of continuous operation in glucose solution and reach 1 mA of current output. Stacks of cells connected in series show successful performance using glucose in Gatorade® resulting in stack-cell potential of 1.8 V, employed to power a digital clock for 36 h, continuously. These designs open the possibility for obtaining enzymatic fuel cells that can run small portable devices on easily available ubiquitous liquids while addressing environmental concerns that are prevalent in traditional fuel cells. Keywords: Enzyme, Bioelectrodes, Enzymatic biofuel cells, Microfluidic system, Capillary driven flow, Bucky paper

High oxygen concentration oxy-fuel circulating fluidized bed (CFB) combustion technology is a high efficiency and low cost oxy-fuel combustion technology, which also has high potential of optimization and efficiency improvement. In this research, energy efficiency is analysed to acquire the effects of flue gas recirculation mode, preheating temperature and oxygen purity on the net efficiency and energy consumption of the 50% oxy-fuel combustion system, so as to obtain the further optimization strategy. The following results are obtained by simulation. The optimal extraction position of recycled flue gas (RFG) is gas preheater outlet, and the net power generation efficiency increases by 0.23% to 25.08%. As the preheating temperature increases from 230 to 400 °C, the net efficiency increases by 1.19% to 26.04%. The net efficiency increases first then decreases as the oxygen purity at ASU outlet increase from 89% to 97.4%, and the optimal value is the 94%. Finally, the optimal system is obtained when RFG is extracted from gas preheater outlet, the preheating temperature is 400 °C and the oxygen purity at ASU outlet is 94%. The net efficiency of the optimization system reaches 27.4%, increasing by 2.55%.

Gasification of biomass is an industrial process utilized to produce product gas that can be used in electrical power generation with internal combustion engines. However, there remain huge challenges with regards to tar and other pollutants, thus their removal before further use is necessary. Non-thermal plasma method can be considered as a novel and efficient way for treatment of tar from product gas. In this work, a laboratory-scale, reverse vortex flow gliding arc plasma reactor was developed and tested for the removal of tar model compound using naphthalene as surrogate. Effects of total gas feed rate in the range of 20–60 L/min, applied voltage in the range of 50–220 V, hence, power input in the range of 300–460 W with initial naphthalene concentration of 610 ± 50 mg/m3 on removal and energy input were investigated. It was found the tar removal efficiency increased with increasing applied voltage. Maximum naphthalene removal efficiency of 85% was achieved at applied high voltage of 15 kV and specific energy input of 0.13 kWh/m3 with energy utilization efficiency of about 4.60 g/kWh. From the findings, non-thermal plasma technology appeared to offer great potential in the removal of biomass tar from gasification. The technology may be promising for possible application to real biomass tar cracking and upgrading of product gas from gasification.

Algeria’s energy demands are tremendously growing, and on the African continent it ranks among the countries with the highest energy consumption. To counter its growing energy demand, the country is progressively adopting renewable energy technologies, although conventional energy technologies still play a central role in its electricity production. The huge solar energy potential in Algeria can be exploited and utilized to meet the country’s growing energy demand with minimal greenhouse gas production. Given that concentrating solar power is viewed as one of the most promising alternatives in the field of solar energy utilization, this study investigates the viability of a 100 MW parabolic trough-based power plant at Tamanrasset, Algeria. The plant was simulated in the System Advisor Model software considering the actual electricity load profile of the targeted location and implementing two different condenser types: evaporative and air-cooled. By comparing the plant’s electricity production to the city’s real load, the plant was in position of supplying about 78% and 60% of the city’s electricity demand during the winter and summer seasons, respectively. The results show that implementation of such CSP plants could play an important role in meeting the energy demand as well as mitigating climate change through greenhouse emissions avoided in electricity generation process.

This article investigates the potential environmental impacts of four-layer printed circuit board (PCB) production from cradle to grave. The study starts with a lifecycle assessment of conventional PCB production. Then, the alternative materials of polyethylene terephthalate (PET), polylactic acid (PLA)/glass fiber composite and paper are investigated for the substrate. A conventional PCB adopts copper as the conductive material and requires an etching process. The environmental impacts of changing the conductive deposition method to an additive method by printing silver nanoparticles is studied. In a conventional PCB, electricity generation contributes 41% of the global warming potential (GWP) and 38% of the abiotic resource depletion (ADP), in the fossil category. By applying an additive manufacturing method, the GWP of PCB manufacturing can be reduced to 14% of that of the conventional method. A sensitivity analysis of silver recycling illustrates that a 40% higher silver recycling rate would decrease the GWP of silver material by about 48–60%. Uncertainty in the energy consumption of PCB production would alter the environmental impacts, however, even with the most conservative energy consumption in a conventional PCB production method, the environmental impacts of the additive method are about five times lower than those of conventional PCB production.

Microbial fuel cells (MFCs) are a green technology that can directly convert electrical energy from chemical energy contained in organic wastewater. Rice is the most popularly consumed food in Asia. Rice washing before cooking produces an enormous amount of domestic sewage. Rice washing wastewater (RWW) contains various organic matters, minerals, and vitamins. Therefore, in this study, we utilized RWW as biofuel to operate a floating MFC (FMFC). The FMFC was designed with the air-cathode floating on the biofuel and the anode immersed in the biofuel. This design enables the device to float on wastewater sources and to harvest electricity directly from that source. Baker’s yeast and bacteria existing in a natural pond (natural bacteria) were used as biocatalysts. Experimental results showed that the FMFC could generate electricity from RWW using both the baker’s yeast and natural bacteria. The maximum power density ow the FMFC using the baker’s yeast was 1 mW/m2.

Environmental concern for our planet has changed significantly over time due to climate change, caused by an increasing population and the subsequent demand for electricity, and thus increased power generation. Considering that natural gas is regarded as a promising fuel for such a purpose, the need to integrate carbon capture technologies in such plants is becoming a necessity, if gas power plants are to be aligned with the reduction of CO2 in the atmosphere, through understanding the capturing efficacy of different absorbents under different operating conditions. Therefore, this study provided for the first time the comparison of available absorbents in relation to amine solvents (MEA, DEA, and DEA) CO2 removal efficiency, cost, and recirculation rate to achieve Climate change action through caron capture without causing absorbent disintegration. The study analyzed Flue under different amine-based solvent solutions (monoethanolamine (MEA), diethanolamine (DEA), and methyldiethanolamine (MDEA)), in order to compare their potential for CO2 reduction under different operating conditions and costs. This was simulated using ProMax 5.0 software modeled as a simple absorber tower to absorb CO2 from flue gas. Furthermore, MEA, DEA, and MDEA adsorbents were used with a temperature of 38 &deg, C and their concentration varied from 10 to 15%. Circulation rates of 200&ndash, 300 m3/h were used for each concentration and solvent. The findings deduced that MEA is a promising solvent compared to DEA and MDEA in terms of the highest CO2 captured, however, it is limited at the top outlet for clean flue gas, which contained 3.6295% of CO2 and less than half a percent of DEA and MDEA, but this can be addressed either by increasing the concentration to 15% or increasing the MEA circulation rate to 300 m3/h.

The looking for sustainable sewage sludge management technology in the wastewater treatment plants, has brought to light the biocathode microbial fuel cells (bMFCs) which allow simultaneous biological stabilization and direct energy generation, avoiding the production of biogas. In the present study, the performance of bMFCs for the treatment of secondary sludge as anodic substrate was evaluated by analyzing the removal of organic matter, destruction of volatile solids and the generation of electrical energy under different operating conditions and applying two types of cathode chambers. The results indicated that VSS and tCOD removals up to 92% and 87% respectively can be achieved in the anodic chamber generating simultaneously energy. Current and power densities of 1.80 ± 0.09 A∙m−3 and 0.43 ± 0.02 W∙m−3 respectively were reached, showing that bMFCs are a reliable alternative to generate electricity during the sewage sludge stabilization process. It was revealed that the pH value and the type of cathodic zone are statistically significant factors that influenced the performance of the bMFCs. The obtained results demonstrated that the electrochemical performance of the bMFCs was better at pH value of 6 in the anodic chamber and when aerobic cathode zone was used.

Papaya (Carica papaya) waste cause significant commercial and environmental damage, mainly due to the economic losses and foul odours they emit when decomposing. Therefore, this work provides an innovative way to generate electricity for the benefit of society and companies dedicated to the import and export of this fruit. Microbial fuel cells are a technology that allows electricity generation. These cells were produced with low-cost materials using zinc and copper electrodes, while a 150 mL polymethylmethacrylate tube was used as a substrate collection chamber (papaya waste). Maximum values of 0.736 ± 0.204 V and 5.57 ± 0.45 mA were generated, while pH values increased from 3.848 to 8.227 ± 0.35 and Brix decreased slowly from the first day. The maximum power density value was 878.38 mW/cm2 at a current density of 7.245 A/cm2 at a maximum voltage of 1072.77 mV. The bacteria were identified with an identity percentage of 99.32% for Achromobacter xylosoxidans species, 99.93% for Acinetobacter bereziniae, and 100.00% for Stenotrophomonas maltophilia. This research gives a new way for the use of papaya waste for bioelectricity generation.

Huge quantities of harvest wastes that are generated from agricultural practices at every farming season in Nigeria are not put into significant use. As an attempt towards adopting these abundant by-products as bioenergy resources for electricity generation, yearly quantities of both cocoa and kolanut harvest residues were estimated in this study. Hygroscopic natures and moisture contents of the two, and their blends, were also analyzed and compared. It was estimated that approximately 681,000 tons and 90,000 tons of cocoa and kolanut husks respectively, are produced in the country annually. While the proximate analyses showed that the sample made of 100% cocoa waste had the least volatile matter and moisture contents in addition to having highest fixed ash and fixed carbon contents, the reverse was the case with the sample made of 100% kolanut waste composition. From the ultimate analyses, however, the latter appears to possess the best characteristic (highest hydrogen and least oxygen contents), but its highest nitrogen content is a pointer to its exhibition of poor thermal property. The gross calorific contents of the samples were, therefore employed for definitive determination of their thermoelectric potentials and these gave higher heating values of 15.19 MJ/kg and 13.87 MJ/kg respectively, with the blends having their values within this range in proportionality to the mass percentage of kolanut husk in the blends. In addition to the two wastes exhibiting good energy characteristics, the study concludes that their blending offers benefit of reduction in ash content. At the optimal blend of equal composition of the two materials (50%CPH/50%KPH), it was estimated that 29,000 MW of electricity is accruable from the wastes., Highlights • Cocoa and kolanut harvest wastes of 681,000 and 90,000 tons respectively, are generated in Nigeria annually. • HHVs of the two agro-residues are 15.19 and 13.87 MJ/kg respectively, with their blends having values within this range. • The optimal blend composition of the two agro-residues has electric power generation potential estimated at 29,000 MW., Agro-wastes, biofuel materials, cocoa pod husk, kolanut pod husk, biomass blends, electrification.

Photothermal‐material‐assisted solar‐steam generation has recently attracted intensive attention due to its superior evaporation rate with high energy conversion efficiency for desalination. In this work, a simple approach for fabrication of porous carbon nanofoam (PCN) is reported, which is prepared by the carbonization of pitch using a combination of CaCO3 and NaCl templates, Meanwhile, NaCl saturated solution acts as a porogen to produce micropores and mesopores as solar receiver for efficient solar steam generation. The as‐prepared PCN shows excellent porosity and mesoporous feature with an average pore size of 26.8 nm. It also shows superior light absorption of 88% and better thermal insulation (thermal conductivity 0.993 W m−1 K−1). Based on these characteristics, the as‐prepared PCN can be used as a promising solar receiver. Under 1 sun, 2 sun, and 3 sun irradiation, the PCN‐based solar receiver shows high energy conversion efficiencies of 88%, 86%, and 84%, respectively. Taking advantage of the abundant, low‐cost, and commercial availability of pitch as well as its simple and cost‐effective manufacture method, the PCN‐based solar receiver may hold great potential for a broad variety of solar‐steam generation applications, for instance, fresh water production, power generation, desalination, and so on., Porous carbon nanofoam derived from the pyrolysis of a CaCO3 nanoparticle/pitch mixture is first prepared as a novel photothermal material, which shows a high evaporation efficiency of 88% under 1 kW m−2 illumination, thus showing great potential for practical solar steam generation.

Sustainable bioelectrogenesis was evaluated by oxidizing the organics of food waste leachate (FWL) under the influence of magnetic field (MF) and short term applied voltage (electric potential, EP). Adaptation of MF (20–220 m T) and EP (100−500 mV) had enhanced the performance of MFC in terms of power generation and reduction of organic in FWL. The best performance of MFC was noted with a MF at 220 m T and EP at 500 mV. MFC under the influence of applied EP (100−500 mV), the power generation was increased from 493 mW/m2 to 832 mW/m2. During this operation, the chemical oxygen demand removal (CODr) was also increased from 51.3 % to 80.4 %. Whereas the control MFC (MFC-C) had exhibited a maximum power generation and CODr of 224 mW/m2 and 36.3 %, respectively. MFC with MF has showed an increase in power density from 480 mW/m2 to 811 mW/m2. MFCs at 220 m T and 500 mV has exhibited, 262 % and 271 % increase in power density over control, respectively. Adaptation of MFC under the EP and MF were found to be beneficial in treating FWL which has high strength organic content.

In this study, response surface methodology (RSM), coupled with central composite design (CCD), are applied to optimise the performance of a microbial fuel cell (MFC) as a function of three main factors of commercialisation. Pt, as the main obstacle for commercialisation in the range of 0.1–0.5 mg/cm2, degree of sulphonation in SPEEK, as a new proton exchange membrane in the range of 20–80%, and rate of aeration of cathode between 10 and 150 ml/min were optimised to identify a more commercial MFC. The single maximum response of power density and COD removal and simultaneous maximisation of both responses were obtained at the corresponding optimal independent variables. The results show that the optimised condition for power density and COD removal is at DS 68% and aeration of 121.62 ml/min. However, the pt load differs and is 0.42 mg/cm2 for produced power density and 0.28 mg/cm2 for COD removal. The maximum produced power density in the optimised situation was 58.19 mW/m2 while the maximum COD removal in the optimised condition was 94.8%. However, once we optimised both at the same time i.e., the power generation and COD removal, the degree of sulphonation (DS) was 68%, Pt load was 0.35 mg/cm2 and the aeration rate was 121.62 ml/min, which resulted in a power production of about 57.06 mW/m2 and COD removal of 92.7%. Keywords: Wastewater treatment, Sustainable energy, Microbial fuel cell, Optimisation, Response surface methodology

Single-chamber microbial fuel cells (MFCs) were constructed using rice bran (carbon source) and pond bottom mud (microbial source). The total electric charge obtained in the MFC combining rice bran with pond bottom mud was four times higher than that in MFC using only rice bran. Phylogenetic analyses revealed dominant growth of fermentative bacteria such as Bacteroides and Clostridium species, and exoelectrogenic Geobacter species in the anode biofilms, suggesting that mutualism of these bacteria is a key factor for effective electricity generation in the MFC. Furthermore, rice bran, consisting of persistent polysaccharide, was pretreated by the hydrodynamic cavitation system to improve the digestibility and enhance the efficiency in MFC, resulting in 26% increase in the total production of electricity.

Digital, The influence of energy recovery from corn cob residues on the environmental performance of the seed-corn supply chain was the main research purpose of this work. An experimental and theoretical analysis as research methods were considered. In this way, an experimental study of corn cob gasification by using air as gasifying agent was conducted, while syngas-based power generation was assessed in a typical gas-ICE. Additionally, life cycle assessment (LCA) of two scenarios (combustion and gasification cases of corn cob residues) for the seed-corn supply chain was accomplished. According to results, a syngas yield in the range of 1.23 and 2.35 Nm3/kg of corn cob was obtained, with LHV close to 5.32 MJ/Nm3. Specific energy recovery from corn cob residues showed, an electricity surplus index of 744 kWh/t corn cob. Moreover, the carbon footprint for both combustion and gasification cases was 913 kg CO2-eq/t seed-corn and 797 kg CO2-eq/t seed-corn, respectively. Integrated thermochemical conversion of corn cob and power generation system represents a technological alternative for its sustainable management. This study provides a holistic inventory, energy balance, and life cycle analysis of corn cob energy utilization. No similar approaches were found in the reviewed literature., Ingeniería Ambiental

In this study, the dilution of anolyte and catholyte as a pH control measure in a newly developed microbial desalination cell (MDC) was explored. Also, the effects of dilution on the newly developed MDC’s electricity generation, desalination and wastewater treatment efficiencies were assessed against a three-chamber MDC which used potassium phosphate buffer for pH control. On the average, the newly developed MDC exhibited a lower buffer capacity (pH change of 1.73 ± 0.06) as compared to the relatively higher buffer capacity (pH change of 1.49 ± 0.07) of the three-chamber MDC. However, the newly developed MDC produced a higher desalination efficiency of 50.01% compared to the 46.66% produced by the three-chamber MDC and a higher power density of 0.62 ± 0.13 W/m3 than the 0.35 ± 0.70 W/m3 produced by the three-chamber MDC. It’s COD reduction efficiency (63.21%) was also higher than the 42.81% produced by the three-chamber MDC.

A microbial fuel cell (MFC) is a device that converts bio-chemical energy into electrical energy during substrate oxidation with the aid of microorganisms (bacteria). The energy contained in waste water is converted to the electrical power by the action of bacteria. The principle of MFC is to transfer electrons from the microorganisms to electron acceptor at a higher electrochemical potential. An experimental study was performed to find the most efficient industrial waste water that can produce highest and stable electrical power by the MFC and to determine the removal rate of pollutant from the waste water by the MFC. Two MFC, namely one PEM MFC and two PEM FMC, has been fabricated for this study. The three different waste water samples used were Dyeing Waste Water-1 (DWW-1), Dairy Industry Waste Water (DIWW) and Dyeing Waste Water-2 (DWW-2). The highest rate of voltage generation is achieved when the MFC was operated with DWW-1 (1.06 V), DIWW (0.95 V) and DWW-2(0.644 V), respectively. Based on the graph pattern the DWW-1 provided the best record in terms of electrical energy generation.

Bacteria are the driving force of the microbial fuel cell (MFC) technology, which benefits from their natural ability to degrade organic matter and generate electricity. The development of an efficient anodic biofilm has a significant impact on the power performance of this technology so it is essential to understand the effects of the inoculum nature on the anodic bacterial diversity and establish its relationship with the power performance of the system. Thus, this work aims at analysing the impact of 3 different types of inoculum: (i) stored urine, (ii) sludge and (iii) effluent from a working MFC, on the microbial community of the anodic biofilm and therefore on the power performance of urine-fed ceramic MFCs. The results showed that MFCs inoculated with sludge outperformed the rest and reached a maximum power output of 40.38 mW&middot, m&minus, 2anode (1.21 mW). The power performance of these systems increased over time whereas the power output by MFCs inoculated either with stored urine or effluent decreased after day 30. These results are directly related to the establishment and adaptation of the microbial community on the anode during the assay. Results showed the direct relationship between the bacterial community composition, originating from the different inocula, and power generation within the MFCs.

Development of economical and environment-friendly Microbial Fuel Cells (MFCs) technology should be associated with waste management. However, current knowledge regarding microbiological bases of electricity production from complex waste substrates is insufficient. In the following study, microbial composition and electricity generation were investigated in MFCs powered with waste volatile fatty acids (VFAs) from anaerobic digestion of primary sludge. Two anode sizes were tested, resulting in organic loading rates (OLRs) of 69.12 and 36.21 mg chemical oxygen demand (COD)/(g MLSS∙d) in MFC1 and MFC2, respectively. Time of MFC operation affected the microbial structure and the use of waste VFAs promoted microbial diversity. High abundance of Deftia sp. and Methanobacterium sp. characterized start-up period in MFCs. During stable operation, higher OLR in MFC1 favored growth of exoelectrogens from Rhodopseudomonas sp. (13.2%) resulting in a higher and more stable electricity production in comparison with MFC2. At a lower OLR in MFC2, the percentage of exoelectrogens in biomass decreased, while the abundance of genera Leucobacter, Frigoribacterium and Phenylobacterium increased. In turn, this efficiently decomposed complex organic substances, favoring high and stable COD removal (over 85%). Independent of the anode size, Clostridium sp. and exoelectrogens belonging to genera Desulfobulbus and Acinetobacter were abundant in MFCs powered with waste VFAs.

International audience; Wood recycling is common practice in most countries. Currently, recovered wood is used for relatively low value uses including energy generation, particleboard manufacture, animal beddings and landscape uses. This paper gives an overview of two research projects that aim to generate high-value products from recovered wood and thereby encourage even higher rates of wood recycling. One project is concerned with the extraction of nano-crystalline cellulose from waste MDF and the other produces laminated beams from recovered wood.

The aim of this work was to study the potentials and benefits of dynamic biogas production from Anaerobic Digestion (AD) of sewage sludge. The biogas production rate was aimed to match the flexible demand for electricity generation and so appropriate feeding regimes were calculated and tested in both pilot and demonstration scale. The results demonstrate that flexibilization capability exists for both conventional AD and advanced AD using Thermal Hydrolysis Process (THP) as pre-treatment. Whilst the former provides lower capability, flexible biogas production was achieved by the latter, as it provides a quick response. In all scenarios, the value of the biogas converted into electricity is higher than with a steady operational regime, increasing by 3.6% on average (up to 5.0%) in conventional and by 4.8% on average (up to 7.1%) with THP. The process has proven scalable up to 18m3 digester capacity in operational conditions like those in full scale.

A biochemical system was used for electricity generation from food waste (FW) and spent animal beddings (SAB). The wastes were blended and fermented anaerobically to produce fermentation liquids used as fuels for running a catalytic fuel cell. The fermentation liquids were analyzed for their components. The results show the organic contents i.e. volatile solids of both FW and SAB to be 23.4 and 20.9 g/L while the carbon contents were 6.5 and 6.1 g/L respectively. The media were however very rich in volatile fatty acids (VFAs). When used, the fermentation liquids from FW and SAB generated mean open-circuit voltages of 0.64 and 0.53 V and mean maximum power densities (Pmean) of 1.6 and 1.3 mW/cm2 respectively. The fuel cell showed very high efficiency in the conversion of all VFAs especially butyric acid with the highest been 97% for FW and 96% for SAB.

The progression of the organic loading rate (OLR) up to a certain limit increases biogas production. The limit and operation range vary according to the configuration of the reactor and are associated with other variables that generate different results with respect to biogas yield (BY) and biogas productiveness (BP). The aim of this study was to investigate the effect of the OLR on the BY and BP from swine manure in continuous stirred tank reactors (CSTRs) and upflow anaerobic sludge blanket reactors (UASBs). In the assay with the CSTR, the best operational condition was at an OLR of 0.7 gVS add L−1 reactor d−1 and a hydraulic retention time (HRT) of 18 days. At this operational condition, 0.8 LN biogas gVS add−1 of BY and 0.6 LN biogas L−1 reactor d−1 of BP were obtained. In the assay with the UASB, the best operational condition was at an OLR of 2.2 gVS add L−1 reactor d−1 and an HRT of two days, and 0.7 LN biogas gvs add−1 of BY and 1.6 LN biogas L−1 reactor d−1 of BP were obtained. The results demonstrate the effects of OLR changes on the biogas production in the CSTR and UASB, avoiding the underutilization or overloading of such equipment and enabling collaboration in projects for power generation from biogas in swine farms. Made available in DSpace on 2020-12-03T09:06:46Z (GMT). No. of bitstreams: 1 final9611.pdf: 537849 bytes, checksum: 6a09ad1dd324fe0066c741f4af6cd36d (MD5) Previous issue date: 2020

Solar energy has become a viable alternative energy because it is a clean type of energy that converts solar radiation into heat energy for various applications such as heating water, power generation, cooking, and food drying. The solar dryer, integrated with the heat energy storage system, uses nitrate salt as a heat storage medium which was designed and tested by drying 1000 grams of red pepper at 19.6 to 62.4°C. The average ambient temperature ranged from 19.3 to 37.4°C, and the maximum temperature of the heat storage media ranged from 87.8 to 125°C. The solar drying process was compared to open sun drying system loaded with 1000 grams of red pepper. The findings showed that the solar dryer maintained color and flavor and lowered the original moisture content from 86% to 10% for 24 hours compared to 36 hours of drying in open air. In this study, nitrate salt is shown to be the perfect heat storage medium for drying food products; it preserved heat for about 4 hours when there is no active sunlight.

Nowadays, microbial fuel cells (MFC) stand up as a promising renewable energy source. Due to the ability of the MFC to oxidize a wide spectrum of substrates, wastewater seems to be one of the most interesting fuels. Unfortunately, wastewater could contain electron acceptors such as nitrate, which could interfere with the electrical performance of the MFC. In this work, the influence of oxidised nitrogen forms on the electricity production of an air breathing MFC was studied. It was observed that power generation was not significantly influenced when operated at nitrate concentrations below 0.9 mg N-NO3 L−1. However, when the nitrate concentrations were above this value, the electricity generation was reduced. In order to investigate the causes of this reduction, an electrochemical characterization of the MFC was performed. The results of polarization curves were fitted to an empirical mathematical model. From the results it was observed that, when nitrate was present, the denitrifiers outcompeted the electrogenic microorganisms for substrate, causing mass transfer limitations to the electrogenic process., Hoy en día, las pilas de combustible microbianas (MFC) se erigen como una fuente de energía renovable prometedora. Debido a la capacidad del MFC para oxidar un amplio espectro de sustratos, las aguas residuales parecen ser uno de los combustibles más interesantes. Desafortunadamente, las aguas residuales podrían contener aceptores de electrones como el nitrato, lo que podría interferir con el rendimiento eléctrico del MFC. En este trabajo, se estudió la influencia de las formas de nitrógeno oxidado en la producción de electricidad de un MFC que respira aire. Se observó que la generación de energía no se veía significativamente influenciada cuando se operaba a concentraciones de nitrato por debajo de 0.9 mg N-NO 3 L -1. Sin embargo, cuando las concentraciones de nitratos estuvieron por encima de este valor, se redujo la generación de electricidad. Para investigar las causas de esta reducción, se realizó una caracterización electroquímica del MFC. Los resultados de las curvas de polarización se ajustaron a un modelo matemático empírico. A partir de los resultados se observó que, cuando estaba presente el nitrato, los desnitrificantes superaban a los microorganismos electrogénicos por sustrato, provocando limitaciones de transferencia de masa al proceso electrogénico.

This study evaluated the performance of a tubular microbial fuel cell (MFC) having a core of air-chamber wrapped with an anion exchange membrane in sewage wastewater treatment. Three MFCs were vertically assembled into one module and floated in sewage water channels before and after treatments in the primary sedimentation tank. The two MFC-modules exhibited nearly similar electricity production in the range of 1.3–5.7 Wh·m−3-MFC while the bottom MFCs (60–90 cm) showed a decrease in electricity compared with the top (0–30 cm) and the middle MFCs (30–60 cm) due to the water leakage into air-cathode. One MFC module was then evaluated for its chemical oxygen demand (COD) removal efficiency with two external resistances of 27 and 3Ω in a chemostat reactor (MFC:reactor = 1:5, v/v) using three hydraulic retention times (HRTs), i.e., 3, 6, and 12 h. The best COD removal efficiency (COD-REMFC), 54 ± 14%, and BOD removal efficiency, 37 ± 17%, were observed with a resistance of 3Ω and a 12 h HRT, which resulted in 3.8 ± 2.0 A·m−3 of current recovery and 15 ± 7.5% of Coulombic efficiency. The electricity generation efficiency (EGEMFC) was the best with a resistance of 27Ω and a 12 h HRT, accounting for 0.19 ± 0.12 kWh·kg-COD−1 with a 17 ± 6.4% COD-REMFC and 0.65 ± 0.10 Wh·m−3 electricity production. Based on calculations using the COD-REMFC and EGEMFC, the integration of MFC treatments prior to aeration can reduce wastewater treatment electricity consumption by 55%.