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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.

Sustainable power generation for portable electronic devices is of high interest due to increasing energy demands. Miniaturized biofuel cells are well-reported for this purpose where ubiquitous fluids, like glucose or lactate, can be leveraged. However, such biofuel cells need enzymes to complete the catalysis, leading to many prevalent issues like the longevity of enzymes, complicated immobilization, additional mediators etc. Therefore, non-enzymatic glucose biofuel cells (NEGBFCs) are gaining interest due to their cost-effectiveness, high repeatability and excellent stability. However, based on our best knowledge such glucose biofuel cells are not reported in microfluidic environment, and therefore their potential is not exploited. Realization of the functionality of such NEGBFCs in a microscale is crucial to replace them with their enzymatic counterparts. In this work, for the first time, a microfluidic non-enzymatic glucose biofuel cell (μNEGBFC) is developed on a paper-based platform using metallic catalysts. The catalysts for electrocatalytic energy generation is fabricated using electrodeposition method and their detailed physicochemical characterizations are done. The μNEGBFC is capable of producing a power density of 12.5 μW/cm2 with a stable potential of 410 mV. This green power output can be used to operate low-power micro-devices and lab-on-chip sensors in a more continual and viable manner.

Microbial fuel cells (MFC) provide a breakthrough development for wastewater treatment combined with electricity production. Though, MFC applications are restricted in laboratory scale level. Present study an effort has been made to employ the electroplating industrial wastewater as feedstock in dual chambered anaerobic microbial fuel cell for organic content removal as well as energy production. The ultimate goal of this research is to analyze the effect of organic load (OL) on removal of organic matter and power production. The maximum removal efficiency of total, soluble oxygen demands (TCOD, SCOD) and total suspended solids (TSS) of about 87%, 79% and 72% respectively was obtained at the OL of 1.5 gCOD/L. The maximum power and current density of about 260 mW/m2 (6.2 W/m3) and 364 mA/m2 was also recorded at a same OL of 1.5 gCOD/L. From the above findings proposed that utilization of high strength organic wastewater in MFC could pave the way to handle the problem of electroplating industries as well as minimize a small portion of energy demand.

The sugar industry is an ideal sector for electricity cogeneration due to a large amount of burnable bagasse produce as a by-product. Bagasse produced in the sugar industry always consists of moisture affecting the efficiency of a boiler in the cogeneration plant. In our case study, a cogeneration plant run by bagasse burning found with bagasse moisture problem and suffocating with low power generation for the last few years. The boiler efficiency per tonne of bagasse is currently lower than optimal due to the substantial percentage of water present in the bagasse. A bagasse dryer design for this industry can improve the efficiency of a boiler as well as the cogeneration plant. In this paper, a pneumatic bagasse drying system is proposed to reduce the moisture content of bagasse from 48% to 30%. This work provides a full analysis of bagasse dryer design parameters, including specifications for dryer system components, such as feeders, fan, drying tube, and cyclone. The total bagasse drying system proposed is expected to be fitted within a 6 x 6 x 25 m space to dry 60 tph of bagasse, reducing the moisture content from 48% to 30%, in full compliance with all relevant Australian and company standards. Resumen La industria azucarera es un sector ideal para la cogeneración eléctrica debido a la gran cantidad de bagazo que se produce como subproducto. El bagazo producido en la industria azucarera siempre consiste en humedad que afecta la eficiencia de una caldera en la planta de cogeneración. En nuestro caso de estudio, una planta de cogeneración operada por la quema de bagazo se encontró con un problema de humedad del bagazo y asfixiada con baja generación de energía durante los últimos años. La eficiencia de la caldera por tonelada de bagazo es actualmente inferior a la óptima debido al porcentaje sustancial de agua presente en el bagazo. Un diseño de secador de bagazo para esta industria puede mejorar la eficiencia de una caldera y de la planta de cogeneración. En este trabajo, se propone un sistema de secado neumático de bagazo para reducir el contenido de humedad del bagazo del 48% al 30%. Este trabajo proporciona un análisis completo de los parámetros de diseño del secador de bagazo, incluidas las especificaciones de los componentes del sistema del secador, como alimentadores, ven tiladores, tubos de secado y ciclones. Se espera que el sistema de secado total de bagazo propuesto se instale en un espacio de 6 x 6 x 25 m para secar 60 tph de bagazo, reduciendo el contenido de humedad del 48% al 30%, en total cumplimiento con todas las normas relevantes de Australia y de la empresa.

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.

Brazilian charcoal is produced from planted eucalyptus forest wood in traditional batch reactors. The ordinary technology applied in Brazil does not use pyrolysis waste gases, which leads to the loss of 30% of wood energy and decreases air quality. This study evaluated the synchronous use of industrial batch kilns, waste gas burning, and energy recovery to produce electricity. Three scenarios were analyzed: (S1) Eucalyptus charcoal production without gas burning (Base Scenario); (S2) with gas burning; and (S3) with gas burning and electricity generation. Since a eucalyptus forest can fix carbon into its biomass through photosynthesis and finally into charcoal, S1 was able to reduce 3402.5 kg of CO2-eq per Mg of charcoal produced, and S2 reduced 6453.1 kg of CO2-eq due to waste gas methane burning. Electricity production is environmentally positive for all evaluated environmental indicators thanks to gas pollutants destruction and renewable energy generation. For S1, a ratio difference of 6.3 was found between the output of renewable energy and fossil energy input during the charcoal life cycle. For a combined production of charcoal and electricity (S3), a ratio difference of 6.9 was found. Photochemical oxidation was the main impact which can be significantly reduced by adopting gas flaring.

The current climate change threat by green house gas emissions from the combustion of fossil fuels has necessitated a search for alternative non-polluting, reliable, renewable and sustainable sources of energy such as solar energy and it’s derivatives. The present work focuses on power generation by Plant-Microbial Fuel Cell using Phragmitesaustralis (Reed plant). The plants were grown in fuel-cell, graphite as anode and carbon felt as cathode, separated by proton-exchange-membrane. During anaerobic microbial metabolism of carbohydrates in the roots, protons and electrons are released, the electrons are donated to the anode by the microbes. These electrons can be channeled through a circuit bearing a load to the cathode. In this work, carbon granules as substratum (control), red soil and carbon granules mixture (30:70) as substratum in varied condition was considered. For control substratum, the max.voltage measured was 0.327 V and power density of 2.06x10-3 mW m-2 was obtained. When red soil mixed with carbon granules in the ratio 30:70, the voltage measured was 0.6 V and the power density was found to be 3.78x10-3 mW m-2. When graded red soil (0.0018 m) mixed with carbon granules in the ratio 30:70, the voltage measured was 0.623 V and the power density was found to be 3.98x10-3 mW m-2. The result proves that the plant microbial fuel cell can be used for generating electricity and is a promising renewable energy technology.

Made available in DSpace on 2022-04-29T08:30:04Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-11-01 Suomen Akatemia This work presents a technical analysis of an Integrated Biomass Direct Gasification/Gas Turbine (BIG-GT) technology within a sugarcane industry to produce electricity and thermal energy (process heat) using bagasse as fuel. Four possible configurations for the implementation of this technology were considered. A sensitivity analysis was made to assess the risks and the uncertainty level for each proposed solution. The results indicated that with the BIG-GT implementation the power generation efficiency increases for all the studied configurations as compared to the conventional system (η = 14.3%). For the configurations I, II, and III the efficiency increase was 9.1%, 11.0% and 12.6%, respectively. However, to support these configurations of the system, the fuel (bagasse) consumption is increased beyond the production capacity of the mill, and the additional amount of bagasse must be acquired to other mills. On the other hand, in configuration IV it is only considered the gasification of the bagasse produced in the mill, being the additional needs of thermal energy for the industrial process supplemented through the combustion of other biomass types (sugarcane straw produced in the mill plantations) in a Heat Recovery Steam Generator. In configuration IV, the electricity generation efficiency is only 5.9% higher than the conventional cycle, this efficiency is getting without the need for an external supply of bagasse. Ultimately, the sensitivity analysis showed that the plant's energy performance with the implementation of BIG-GT technology is particularly sensitive to variations related to the gasifier's efficiency. UNESP-Sao Paulo State University Faculty of Engineering Campus of Guaratinguetá Bioenergy Research Institute (IPBEN-UNESP) Laboratory of Energy Systems Optimization (LOSE), Av. Dr. Ariberto Pereirada Cunha, 333 Portal Das Colinas Guaratinguetá University of Oriente Efficiency Energy Study Center (Faculty of Mechanical Engineering) Julio Antonio Mella Headquarters, Ave de Las Américas y Casero Department of Environment and Planning - Centre for Environmental and Marine Studies (CESAM) University of Aveiro Campus Universitário de Santiago Polytechnic Institute of Portalegre Instituto Superior Técnico University of Lisbon UNESP-Sao Paulo State University Faculty of Engineering Campus of Guaratinguetá Bioenergy Research Institute (IPBEN-UNESP) Laboratory of Energy Systems Optimization (LOSE), Av. Dr. Ariberto Pereirada Cunha, 333 Portal Das Colinas Guaratinguetá Suomen Akatemia: 320229

Oil palm empty fruit bunch (EFB) biomass valorisation for high-value applications has been a current focus in research due to the vast amount of biomass generated from the daily operation of palm oil mills. EFBs can be utilized to produce high-value nanomaterials such as cellulose nanocrystals (CNCs), lignin-containing cellulose nanocrystals (LCNCs) and nanolignin (NL), as well as value-added products such as syngas, ammonia, methanol and electricity. More often, a single product processing pathway from EFBs entails a higher production cost relative to conventional petroleum feedstock. Therefore, the biorefinery concept is exploited to liberate the huge economic potentials of these products. However, different biorefinery schemes would have different environmental and economic performances. Thus, the evaluation of environmental and economic performances associated with various schemes of oil palm biorefineries is carried out in a two-step approach to provide future guidance in selecting suitable schemes for oil palm biorefineries. In the first step, a comparison of the environmental and economic performances of three different nanomaterial plants—CNC, LCNC and NL plants—was performed, and the results showed that the LCNC plant had the best environmental performance, while the NL plant had the highest profit margin. These nanomaterials serve as the core products for the development of biorefineries. In the second step, various nanomaterials, chemical products and power plants are integrated together to form a biorefinery. The scheme with LCNC and NL plants and power generation pathways via gasification yields the lowest environmental impact and highest profit margin. This analysis provides an early stage evaluation for future nanomaterial biorefineries from environmental and economic perspectives.

Jatropha is a tropical herb and can be matured in a diverse soil with low to high rainfall. It provides a chunk of the fuel supply in the transportation and energy sectors. Jatropha biodiesel implies a diesel equivalent and consist of methyl esters. It is produced through the transesterification process which is a chemical reaction of jatropha oil with an alcohol in the presence of a catalyst. In the present work, the physical and chemical attributes of jatropha biodiesel were determined. Various blended samples of jatropha biodiesel with mineral diesel were used to run diesel engine to see the variation of the brake power, brake specific fuel consumption and brake thermal efficiency of engine with percentage increase of jatropha biodiesel in the mixture. It was observed that these properties remain unchanged for 5% and 10% blend of jatropha biodiesel to mineral diesel and hence its use is quite feasible without any change in engine design. This provides an edge to the countries having surplus lands in low rain areas to generate 10% of their energy resources for power generation and transport through the cultivation and growth of jatropha plants.

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.

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.

In the present study, a multigeneration system using corn stalk as biomass and solar energy at specific thermodynamical conditions by hydrothermal gasification method from zero to the maximum temperature (1000 °C) for hydrogen and power production is designated and analyzed. Thermal performance analysis is done by availing energy and exergy computation for each facility and system at different temperatures, pressures, and flow rates. Furthermore, the system was simulated via Aspen Plus software with the help of the Peng-Robinson method. Moreover, according to inputs, products’ amounts, and the conditions, the system generates power and clean water, which this combination has not done earlier. The obtained energy from the collector supplied the reactor’s energy; in addition, the system generated power by a turbine, that the power generated by the system and solar collector as 788 and 2567 kW. The hydrogen gas in the highest value attained as 0.0197 kg/s at 1000 °C, 0.7 kg/s mixing input, and the significant pressure 250bar. Moreover, CO and CH4 gases and clean water were surveyed as other products, and 0.365, 0.666 kg/s, and 0.248 kg/s were obtained. The total energy and exergy efficiencies of the system were determined 57.5% and 38.3%, respectively. Also, the hydrogen production exergy efficiency was calculated as 16.5%, and the maximum exergy destruction was 2559 kW that belonged to the reactor. Furthermore, the exergy efficiency of solar energy was 76.7%. Utilizing some catalysts and combining biomasses with adding ammonia to the desired productions would be a novel future study.

In a typical microbial electrochemical system (MES) with dual-chamber for Cr(VI) reduction, it was faced with the decline of Cr(VI) reduction efficiency after several cycles of operation, which limited the continuous and effective Cr(VI) reduction of MES. In this study, a novel bioelectrochemical reactor assembled with cooperative cathodes of chemical cathode and bio-cathode (BERCC) and with excess sludge as anodic substrate was designed to solve the problem. Comparative study of BERCC and BER with dual chemical cathodes (BERDC) revealed that BERCC broke through the limitation of Cr(VI) reduction decline for cycles of operation and improved performance of electricity generation. Both the Cr(VI) reduction rate and the power density were increased with the decrease of pH and the increase of TCOD and initial Cr(VI) concentration. Cooperative cathodes stimulated the growth of electrochemically active microorganisms in the anodic biofilm and produced 8.21±0.64 mg Coulomb/(L·h) more electrons than dual chemical cathodes, which enhanced the electrons for electricity generation and Cr(VI) reduction by about 58.3% and 56.1±5.6% in BERCC than those in BERDC.

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.

Bagasse has traditionally inefficiently burned in boilers for steam and electricity generation which still suffers from significant inefficiencies creating; therefore there is a need for alternative processes to be analyzed. Among the biomass utilization technologies, biomass gasification is an attractive solution for utilizing biomass effectively. In this study Aspen Plus simulation package V8 was used to develop a model for the gasification of Sudanese sugar cane bagasse in a fluidized bed reactor for syngas production. The developed model is based on Gibbs free energy minimization applying the non-stoichiometric equilibrium method for optimization of the gasifier performance. The objective is to study the effect of important operating parameters including gasification temperature, steam to biomass ratio (SBR) and air to biomass ratio (ABR), on syngas composition, low heating value (LHV) of syngas and cold gas efficiency (CGE). The optimal values of syngas composition, LHV and CGE were located at gasification temperature range from 750C to 950C, steam to biomass ratio around 0.5 to 0.8 and air to biomass ratio values equal to or below 0.4.

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.

Microbial fuel cells (MFCs) have emerged as a promising technology for energy-efficient wastewater treatment. The feasibility of integrating biological nitrogen removal into MFC systems has been reported. However, better pollutant removal efficiency and power production need to be achieved at a lower cost for a sustainable wastewater treatment system. The objective of this paper is to critically review the nitrogen removal process in various MFC configurations, factors that influence this process, and challenges that should be overcome in future studies. Based on the results of the review, shortcut nitrification-autotrophic denitrification in an MFC is an option as it minimizes the aeration energy and C/N ratio requirement; however, it is necessary to evaluate the N2O emission further. Another attractive option is the heterotrophic anodic denitrification process as it demonstrates the potential for free-buffer MFCs, but the nitrogen removal efficiency at low C/N ratios needs improvement. Bacteria population in MFC system also plays an essential role in both contaminant removal and electricity generation. It can be concluded that MFCs can be a low cost, sustainable solution for the treatment of wastewater and removal of nitrogen. Moreover, selection of MFC configuration will depend on the nature of the wastewater.

This paper illustrates the potential of unicellular microalgae in electricity production in concurrence with wastewater treatment. Our study focused on the isolation of microalgal strains from various aquatic sources. Cyclic voltammetry was performed to detect the electrogenic activity and out of 18 algal isolates, six algal strains were screened. Coelastrella sp. from the paddy field revealed the well-defined redox peak and its analyzed EPS production was 13.79 mg/ml which paves way to hydrated biofilm matrix assisting in better electrogenicity. Its potential to remove nutrients in wastewater was assessed under lab-scale race way pond. Significant decrease in N, P, BOD, COD, and TOC was observed. The removal efficiency of NH4-N, NO3-N, P, BOD, COD and TOC were 90.38, 90.24, 66.75, 67.15, 69.44, and 83.51 respectively. To the best of our knowledge, EPS production, electrogenic activity and their utility in waste water treatment are reported for the first time in Coelastrella sp.

This paper shows use of cow dung compost soil as a biocatalyst to optimize the urea fuel concentrations in the range of 0.1 g/ml to 0.5 g/ml in cow dung compost microbial fuel cells (CC-MFCs). The results indicate that the CC-MFC with the urea fuel concentration of 0.4 g/ml produces the maximum power. Moreover, the bacterial population plays a vital role in electricity generation. For constant cell operation and cell sustainability, it must be refuelled with the catalyst after every 12 h cycle and the max power density was generated 17.84mW/m2 by CC-MFC. This study confirms for the first time that cow dung compost directly works as a noval biocatalyst. Here primary focus is to generate power through soil processes using urea-rich wastewaters (urine) as fuel. CC-MFCs are inexpensive, non-toxic, leakage proof, low maintenance, less labour intensive, durable, stable, easily disposable, sustainable, and efficient. Moreover, these fuel cells can generate clean energy without biocatalyst deactivation. Research is going on fabrication and development of CC-MFC for application depend upon the type of urea rich urine wastewater used as fuel for power generation and cleaning the environment.

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.

This work assesses scale effects in designing a biorefinery from Sargassum muticum seaweed by applying a detailed process modeling methodology. Two process conversion units were simulated: one considering anaerobic digestion steps for producing biogas and generating electricity (base project), and the other with residual seaweed solids sold as fertilizer (alternative project). A comprehensive economic analysis was performed to estimate the minimum selling price of the process's main product (fucoidan extract). Results indicated that capital expenditures are up to 12.7% times higher in the base project. Minimum selling prices of the fucoidan extract product demonstrate the biorefinery's economies of scale for both projects. Seaweed's low methane potential reduces the economic attractiveness of electricity generation from biogas in the base project. Conversely, organic fertilizer price was more influential in the alternative project. Nonetheless, risk analyses show similar results for both scenarios, mainly due to fucoidan extract selling price and CAPEX estimates uncertainties.

An integrated system was developed to simultaneously produce ammonia and power using biomass as feedstock. The proposed system has the following subsystems: (i) self-heat recuperation-based drying to significantly reduce energy consumption, (ii) direct chemical looping hydrogen production with two-stage combustion to obtain highly purified hydrogen and nitrogen, (iii) Haber-Bosch (H-B) process to produce ammonia, and (iv) Brayton-Rankine combined cycle to exploit the thermal energy of purged gas from the H-B process. In-depth exergy and exergoeconomic analyses were performed. Self-heat recuperation-based drying achieved an energy-saving ratio of up to 93.4% compared to traditional drying. Exergy analysis showed that the exergetic efficiencies of ammonia and net power production were 44.36% and 1.73%, respectively. The largest exergy destruction occurred in the fuel reactor, accounting for approximately 28% of the total exergy destruction. Exergoeconomic analysis revealed that refrigerator and some pressure-changing components (MComp1, Comp, MComp2, and EXP1) have higher cost reduction potential; a decrease in cost rates ( Z K s) (as well as purchasing costs) of these components is necessary for system cost reduction. The final product cost allocation demonstrated that the unit costs of ammonia and electricity were 29 USD/GJ and 140 USD/GJ, respectively, under the initial input parameters.

Bioethanol is widely perceived as a clean fuel that can be used directly as automobile fuel or blended with petrol without engine modification. Similarly, biomethane can be used as an environmentally friendly substitute to natural gas for diverse applications such as transportation, heating, and electricity generation. Recently, there has been a growing interest in the cost-effective and sustainable production of both these biofuels. The present study reveals a conceptual design for biomethane and bioethanol production from crude glycerol obtained from the biodiesel industry. The techno-economic feasibility of three different scenarios was assessed. Scenario 1 is based on bioethanol production by coupling hydrothermal gasification and syngas fermentation. Scenario 2 consists of hydrothermal gasification, syngas fermentation, and CO2 capture unit. In scenario 3, biomethanation and electrolytic unit were added to scenario 2 to convert CO2 to biomethane. The energy efficiency of the scenarios examined ranges from 30.2% to 35.1%. Scenario 3 had the highest energy efficiency of 35.1%. Moreover, the minimum selling price of bioethanol declined in the following order: scenario 2 (USD $1.4 per liter) > scenario 1 (USD $1.32 per liter) > scenario 3 (USD $0.31 per liter). The discounted cash flow analysis results indicated that scenario 3 is the most profitable because of its non-discounted net present value of USD $34.9 million compared to the other case studies. Sensitivity analysis reveals that electricity and glycerol cost had the most effect on the minimum selling price of bioethanol.

Safe disposal of effluent from palm oil production poses an environmental concern. The highly polluting effluent is customarily treated by unsustainable open ponds with low efficiency, direct emissions, and massive land use. This study looks into an application of integrated anaerobic/oxic/oxic scheme for treatment of high strength palm oil mill effluent. The anaerobic reactors functioned as a prime degrader that removed up to 97.5% of the chemical oxygen demand (COD), while the aerobic reactors played a role of an effluent polisher that further reduced the COD. Their complementing roles resulted in a remarkable removal of 99.7%. Assessment of emission mitigation and biogas energy revealed that yearly energy of 53.2 TJ, emissions reduction of 239,237 tCO2 and revenue of USD 1.40 millions can be generated out of electricity generation and heating. The integrated scheme provides a viable and sustainable treatment of the high strength palm oil mill effluent.

Citric acid (CA) production wastewater has been attracting wide attention because of its potential threat to environment and public health. Microbial fuel cell (MFC) can satisfy the urgent demands of high efficiency, last sustainability and environmental-friendly wastewater treatment. In this work, the performance of MFC towards CA degradation and the corresponding power generation were both investigated. Four different contents of CA (5 mM, 10 mM, 25 mM, 40 mM) were selected for preparation of stimulated wastewater, and the maximum chemical oxygen demand (COD) removal and power density reached to 79.4% and 610 mW/m2, respectively at the CA content of 25 mM. Besides, the decrease of influent pH from 7 to 4 can reduce the electrochemical properties of microorganisms, while negligible effect on electricity generation was observed with pH higher than 6. Besides, the addition of riboflavin as redox mediators enhanced power generation and COD removal rate simultaneously, which increased from 611 mW/m2, 79.4% to 855.2 mW/m2, 84.5% respectively. Significantly, anodic microorganisms can survive well in the presence of 40 mM citric acid and remain its electricity generation and degradation capability simultaneously by sequencing analysis. Therefore, it is anticipated that the MFC system seems to be a promising technology for organic wastewater treatment effectively and accessibly.