Exergo-enviro-economic and yearly productivity analyses of conical passive solar still for sustainable solar distillation.

This paper focuses on exergo-enviro-economic and yearly productivity analyses for conical passive solar still having the potential to fulfil the sustainable development goal of the United Nations. A new approach for thermal modelling of conical passive solar still has been carried out with experimental validation in the present work, wherein different weather conditions have been considered for the analysis of the proposed system. The carried out work has been done for each month of the year. In further methodology, the computational code in MATLAB has been used for the computation of hourly freshwater production, exergy, and energy followed by the estimation of their annual values. Thereafter, exergo-enviro-economic parameters, yearly productivity, payback period, and freshwater cost have been estimated, and the obtained results have been compared with the earlier published research. Concludingly, the exergo-economic parameter, enviro-economic parameter, and yearly productivity for the proposed system have been found higher by 44.25%, 25.68%, and 44.07%, respectively, than the conventional solar still. The comparative freshwater cost is 13.56% less than the conventional solar still for 0.025 m water depth. Additionally, the payback period for the proposed system will remain at 2.75 years, which is 13.82% less in comparison to the conventional solar still considering a 2% interest rate.

Electrospun nanofibrous membranes for membrane distillation application-A dynamic life cycle assessment (dLCA) approach.

Membrane distillation (MD) for water desalination and purification has been gaining prominence to address the issues relating to water security and the destruction of aquatic ecosystems globally. Recent advances in electrospun membranes for MD application have improved antifouling and anti-wetting performance. However, the environmental impacts associated with producing novel electrospun membranes still need to be clarified. It is imperative to quantify and analyze the tradeoffs between membrane performance and impacts at the early stages of research on these novel membranes. Life Cycle Assessment (LCA) is an appropriate tool to systematically account for environmental performance, all the way from raw material extraction to the disposal of any product, process, or technology. The inherent lack of detailed datasets for emerging technologies contributes to significant uncertainties, making the adoption of traditional LCA challenging. A dynamic LCA (dLCA) is performed to guide the sustainable design and selection of emerging electrospun poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) electrospun membrane (E-PH) and hybridizing polydimethylsiloxane (PDMS) on E-PH membrane (E-PDMS) for dyeing wastewater treatment technologies. The associated environmental impacts are related to the high energy demands required for fabricating electrospun nanofibrous membranes. After LCA analysis, the E-PDMS membrane emerges as a promising membrane, due to the relatively low impact/benefit ratio and the high performance achieved in treating dyeing wastewater.

Annual thermal performance analysis and economic assessment of an evacuated tube coupled solar still for Indian climatic conditions.

In this experimental study, the annual performance and economic analysis of an evacuated tube augmented solar still is presented from June 2020 to May 2021. The experiments are also performed simultaneously on a conventional still as well. The experiments are performed throughout the year at 6 cm water depth for both solar stills in the climate of Kurukshetra City, India. The main output parameters, namely, maximum daily water output, maximum hourly water output, thermal efficiency, and maximum basin water temperature have been taken into account and represented in this study. In addition, thermal analysis for both solar stills is performed in this study. The results from experimentation showed 149% improvement in the daily freshwater output from the modified still in comparison to the conventional still. Also, an increase of 1.7% in overall thermal efficiency is achieved for the modified still in comparison to the conventional still. The maximum still performance is achieved in the month of June 2020. In the economic analysis, the cost of water obtained per litre after distillation is $0.0098 for a conventional still and $0.022 in the case of a modified still.

Techno-enviro-economic assessment of novel hybrid inclined-multi-effect vertical diffusion solar still for sustainable water distillation.

A novel hybrid inclined-multi effect vertical diffusion (Hybrid I-MEVD) solar still has been proposed and its viability for sustainable water distillation has been assessed based on detailed techno-enviro-economic aspects. The optimum number of diffusion chambers and recommended diffusion gap of integrated MEVD still was estimated to be 4 and 0.01 m, respectively. Incorporation of the bottom reflector at yearly average optimum tilt angle enhanced yield by about 34.0 to 90.0%. Yearly average distillate yield, coefficient of performance, and exergy efficiency were about 21.35 kg/day, 1.05, and 10.44%, respectively. Net carbon-di-oxide, sulphur-di-oxide, and nitrogen oxide emission mitigation potential ranged between 37.02 to 65.05 tons, 266.20 to 467.71 kg and 108.73 to 191.04 kg, respectively. Global warming potential, acidification potential, photochemical oxidants creation potential, eutrophication potential, and human toxicity potential were about 67.25 kg of CO2/kL of distillate, 591.04 g of SO2/kL of distillate, 178.63 g of C2H4/kL of distillate, 23.22 g of PO4/kL of distillate, and 698.53 g of DCB/kL of distillate, respectively. The minimum distillate production cost was estimated to be about 13.3 USD/kL. High distillate production rate, minimal environmental footprint, and distillate production cost justify Hybrid I-MEVD still to be a sustainable option for potable water production in fresh water-starved regions.

Decarbonized and circular brine management/valorization for water & valuable resource recovery via minimal/zero liquid discharge (MLD/ZLD) strategies.

Brine (saline wastewater/water) from desalination, salt lakes, and industrial activities (e.g., pharmaceutical industries, oil & gas industries) has received a lot of attention around the world due to its adverse impact on the environment. Currently, several disposal methods have been applied; however, these methods are nowadays unsustainable. To tackle this problem, brine treatment and valorization is considered a promising strategy to eliminate brine discharge and recover valuable resources such as water, minerals, salts, metals, and energy. Brine valorization and resource recovery can be achieved via minimal and zero liquid discharge (MLD & ZLD) desalination systems. Commercially successful technologies such as reverse osmosis (RO) and distillation cannot be adopted as standalone technologies due to restrictions (e.g., osmotic pressure, high-energy/corrosion). Nonetheless, novel technologies such as forward osmosis (FO), membrane distillation (MD) can treat brine of high salinity and present high recovery rates. The extraction of several ions from brines is technically feasible. The minerals/salts composed of major ions (i.e., Na+, Cl-, Mg2+, Ca2+) can be useful in a variety of sectors, and their sale prices are reasonable. On the other hand, the extraction of scarce metals such as lithium, rubidium, and cesium can be extremely profitable as their sale prices are extremely higher compared to the sale prices of common salts. Nonetheless, the extraction of such precious metals is currently restricted to a laboratory scale. The MLD/ZLD systems have high energy consumption and thus are associated with high GHGs emissions as fossil fuels are commonly burned to produce the required energy. To make the MLD/ZLD systems more eco-friendly and carbon-neutral, the authors suggest integrating renewable energy sources such as solar energy, wind energy, geothermal energy, etc. Besides water, minerals, salts, metals, and energy can be harvested from brine. In particular, salinity gradient power can be generated. Salinity gradient power technologies have shown great potential in several bench-scale and pilot-scale implementations. Nonetheless, several improvements are required to promote their large-scale feasibility and viability. To establish a CO2-free and circular global economy, intensive research and development efforts should continue to be directed toward brine valorization and resource recovery using MLD/ZLD systems.

Exploitation of distillation region diagrams for energy-efficient and cost-effective treatment of a hazardous effluent discharged from semi-conductor industries.

The hazardous nature of certain azeotropic mixtures has urged the researchers to explore the separation techniques which can impart a contamination free environment. Despite of causing environmental concerns, these azeotropic mixtures are responsible for causing serious health issues to humans and animals. More specifically, in this article, we have taken Tetrahydrofuran (THF) - water azeotropic mixture into consideration. It has been reported that it affects the central nervous system, liver, as well as can cause carcinogenicity. To be more precise, in this article, two different entrainers has been evaluated on their merits of exploiting liquid-liquid phase envelope for separating Tetrahydrofuran-water binary azeotropic mixture. The process flow sheet schematic with n-octane as entrainer (having two distillation regions) has a reduced operating energy requirement by 21.11% while comparing with the Residue Curve Map of n-hexane as entrainer having three distillation regions. The total capital cost for THF-water-n-octane case has been found to be 7.1 $/y × 105 and that of THF-water-n-hexane case has been found to be 9 $/y × 105. However, in both of the cases, the product purity of 99.9% has been achieved for THF. Also, the classical trade-off between capital cost and energy cost has been shown in this study. The salient feature of this work is the use of dynamic simulation to understand the effect of recycle flow rate induced process operational in-feasibility due to distillation region shift.

Exploitation of distillation for energy-efficient and cost-effective environmentally benign process of waste solvents recovery from semiconductor industry.

The waste solvent is unavoidably generated from the high solvent dependable processes. One of them is the semiconductor industry. The waste solvent is frequently incinerated to eliminate hazardous waste and this practice raises the issue of environmental and treatment costs. Thus, recovery of waste solvent is a substantial environmental mitigation option. This study explores the recovery of multicomponent waste solvents from the semiconductor industry. To achieve a greener and energy-efficient process, the recovery process is proposed through investigation of mixture thermodynamic behavior, process design, optimization, economics, and integration of renewable energy for environmental advantages. Herein, Distillation, a practical technology option for solvent recovery, with green solvent for extractive distillation and a new approach using renewable energy in waste solvent recovery are explored. As the result, waste solvent recovery by distillation with conventional energy exhibits bold advantages to cost and lower carbon process compared to waste disposal. The integration of renewable energy with about 37 % share of conventional energy as the backup indicates the highest annual cost-saving and reduces about 89.4 % of annual carbon emission compared to carbon emission from waste disposal.

Feasibility assessment of bioethanol production from humic acid-assisted alkaline pretreated Kentucky bluegrass (Poa pratensis L.) followed by downstream enrichment using direct contact membrane distillation.

The effective fractionation of structural components of abundantly available lignocellulosic biomass is essential to unlock its full biorefinery potential. In this study, the feasibility of humic acid on the pretreatment of Kentucky bluegrass biomass in alkaline condition was assessed to separate 70.1% lignin and hydrolyzable biocomponents. The humic acid-assisted delignification followed by enzymatic saccharification yielded 0.55 g/g of reducing sugars from 7.5% (w/v) pretreated biomass loading and 16 FPU/g of cellulase. Yeast fermentation of the biomass hydrolysate produced 76.6% (w/w) ethanol, which was subsequently separated and concentrated using direct contact membrane distillation. The hydrophobic microporous flat-sheet membrane housed in a rectangular-shaped crossflow module and counter-current mode of flow of the feed (hot) and distillate (cold) streams yielded a flux of 11.6 kg EtOH/m2/24 h. A modular, compact, flexible, and eco-friendly membrane-integrated hybrid approach is used for the first time to effectively valorize Kentucky bluegrass biomass for sustainable production of biofuel.

A chemometric assessment and profiling of the essential oils from Hibiscus sabdariffa L. from Kurdistan, Iraq.

Hibiscus sabdariffa L. is a tropical plant belonging to the Malvaceae family. In Kurdistan, the Autonomous Region of Iraq, water infusion of H. sabdariffa calyces is recommended for the treatment of hypotension and the common cold. Three distillation techniques: hydrodistillation (HD), steam distillation (SD), and solvent-free microwave-assisted extraction (SFME) have been compared to obtain the essential oils from calyces. The composition of the extracts was investigated by GC-FID and GC-MS. A total of 62 compounds have been identified, from which 55 components were found in HD distillates (95.75%), 37 components in SFME (96.06%), and 29 in SD (99.63%). Chemometric tools were applied to optimise and evidence the relation between distillation techniques and composition of the obtained essential oils as an investigation for the essential oils commercialisation approach of Hibiscus sabdariffa L. that have been done from a long time using conventional hydrodistillation in the local Herbal and Tea markets in Kurdistan.

Membrane distillation crystallization technology for zero liquid discharge and resource recovery: Opportunities, challenges and futuristic perspectives.

Water resources are getting limited, which emphasises the need for the reuse of wastewater. The conventional waste(water) treatment methods such as reverse osmosis (RO) and multi-effect distillation (MED) are rendered limited due to certain limitations. Moreover, the imposition of stringent environmental regulations in terms of zero liquid discharge (ZLD) of wastewater containing very high dissolved solids has assisted in developing technologies for the recovery of water and useful solids. Membrane distillation crystallization (MDCr) is an emerging hybrid technology synergising membrane distillation (MD) and crystallization, thus achieving ZLD. MDCr technology can be applied to desalinate seawater, treat nano-filtration, and RO reject brine and industrial wastewater to increase water recovery and yield useful solids. This manuscript focuses on recent advances in MDCr, emphasizing models that account for application in (waste)water treatment. MDCr has dual benefits, first the environmental conservation due to non-disposal of wastewater and second, resources recovery proving the proverb that waste is a misplaced resource. Limitations of standalone MD and crystallization are discussed to underline the evolution of MDCr. In this review, MDCr's ability and feasibility in the treatment of industrial wastewater are highlighted. This manuscript also examines the operational issues, including crystal deposition (scaling) on the membrane surface, pore wetting phenomenon and economic consequences (energy use and operating costs). Finally, opportunities and future prospects of the MDCr technology are discussed. MDCr technology can amplify natural resources availability by recovering freshwater and useful minerals from the waste stream, thus compensating for the relatively high cost of the technology.

Assessment of pilot direct contact membrane distillation regeneration of lithium chloride solution in liquid desiccant air-conditioning systems using computer simulation.

Membrane distillation (MD) has been increasingly explored for treatment of various hyper saline waters, including lithium chloride (LiCl) solutions used in liquid desiccant air-conditioning (LDAC) systems. In this study, the regeneration of liquid desiccant LiCl solution by a pilot direct contact membrane distillation (DCMD) process is assessed using computer simulation. Unlike previous experimental investigations, the simulation allows to incorporate both temperature and concentration polarisation effects in the analysis of heat and mass transfer through the membrane, thus enabling the systematic assessment of the pilot DCMD regeneration of the LiCl solution. The simulation results demonstrate distinctive profiles of water flux, thermal efficiency, and LiCl concentration along the membrane under cocurrent and counter-current flow modes, and the pilot DCMD process under counter-current flow is superior to that under cocurrent flow regarding the process thermal efficiency and LiCl concentration enrichment. Moreover, for the pilot DCMD regeneration of LiCl solution under the counter-current flow, the feed inlet temperature, LiCl concentration, and especially the membrane leaf length exert profound impacts on the process performance: the process water flux halves from 12 to 6 L/(m2·h) whilst thermal efficiency decreases by 20% from 0.46 to 0.37 when the membrane leaf length increases from 0.5 to 1.5 m.

Performance assessment of conventional solar desalination system in Northern part of Gujarat.

Water distillation by utilising free energy from the sun is one of the significant techniques for getting freshwater from salty and seawater. For the remote areas and small societies where freshwater is distant, solar distillation is one of the best explanations for freshwater creation. The main objective of this study is to evaluate the performance of the flat plate collector-assisted conventional solar still incorporating mirror wall and heat storage material, which was tested at Anchor institute of solar energy studies, Mehsana (23.5275311° latitude and 72.3881041° longitude), Gujarat. Moreover, the study captures average productivity with and without FPC which was 1.5 L and 1.0 L respectively during the day time for the entire period of experiments. In this study, the water depth is varied from 1 to 5 cm inside the single basin solar still to obtain the optimum depth. It was observed that when mirror augmented still was operated with the FPC, 3.6L/day productivity was achieved with 30% instantaneous efficiency, at solar radiation of 1122 W/m2 and ambient temperature of 24 °C. Also, the maximum productivity was observed at a water depth of 3 cm and 4 cm. Moreover, improvements in daily and yearly productivity were observed to be 51.515% and 56.6474% respectively, which were estimated on the basis of with and without FPC. An experiment was performed at Anchor Institute of Solar Energy, Mehsana located at the north part of Gujarat where the average annual rain was comparatively less compared to other regions, so this type of solar still can provide potable water to daily workers who work on site. Furthermore, economic study reveals 0.577 INR/litre cost of distiller output for conventional set-up and 0.477 INR/litre for the FPC assisted set-up.

Tocopherol contents and antioxidant activity in grape pomace after fermentation and alcohol distillation.

The wine industry in Georgia produces vast amounts of grape pomace that is currently mostly wasted, while only a minor amount is used for distilling alcohol. The study was carried out on the grape pomace from the three most widely used grapevine sorts (Vitis vinifera var. Rkatsiteli, V. vinifera var. Saperavi, V. labrusca var. Isabella)  in Georgia, and quantities of tocopherols and antioxidants were evaluated. The antioxidant activity was assessed by diphenyl-picrylhydrazyl (DPPH) and measurement of visible light absorption at 515 nm, and tocopherol was measured by absorption at 470 nm via a spectrophotometer. The results indicated that the grape pomace contains considerable tocopherols and antioxidant activity. However, the antioxidant activity had slightly been decreased. These results suggest that grape pomace can be an economically attractive resource for the pharmaceutical and food industries. Utilization of grape pomace for producing pharmaceutical and cosmetic goods with tocopherol and antioxidants can solve two problems: it can recycle waste and develop new profitable businesses in biotechnology.

Extraction of Peppermint Essential Oils and Lipophilic Compounds: Assessment of Process Kinetics and Environmental Impacts with Multiple Techniques.

Consumers are becoming more mindful of their well-being. Increasing awareness of the many beneficial properties of peppermint essential oil (EO) has significantly increased product sales in recent years. Hydrodistillation (HD), a proven conventional method, and a possible alternative in the form of microwave-assisted hydrodistillation (MWHD) have been used to isolate peppermint EO. Standard Soxhlet and alternatively supercritical fluid (SFE), microwave-assisted, and ultrasound-assisted extraction separated the lipid extracts. The distillations employed various power settings, and the EO yield varied from 0.15 to 0.80%. The estimated environmental impact in terms of electricity consumption and CO2 emissions suggested that MWHD is an energy efficient way to reduce CO2 emissions. Different extraction methods and solvent properties affected the lipid extract yield, which ranged from 2.55 to 5.36%. According to the corresponding values of statistical parameters, empiric mathematical models were successfully applied to model the kinetics of MWHD and SFE processes.

Solar distillation of highly saline produced water using low-cost and high-performance carbon black and airlaid paper-based evaporator (CAPER).

The current technologies to treat hypersaline produced water (PW), such as thermal evaporation, are usually energy-intensive and cost-prohibitive. This study developed a low-cost, robust, solar-driven carbon black and airlaid paper-based evaporator (CAPER) for desalination of PW in the Permian Basin, United States. The study aims to better understand the removal of aromatic organic compounds and heavy metals during solar distillation, water output, and heat transfer. Outdoor experiments using CAPER assisted with polystyrene foam in a single slope, single basin solar still achieved an enhanced average evaporation rate of 2.23 L per m2 per day, 165% higher than that of a conventional solar still. Analysis of heat transfer models demonstrated that CAPER solar evaporation achieved an evaporative heat transfer coefficient of ∼28.9 W m-2·K-1, 27.9% higher than without CAPER. The maximum fractional energy of evaporation and convection heat transfer inside the solar still with and without CAPER was ∼81.4% and ∼78.2%, respectively. For the PW with a total dissolved solids concentration of 134 g L-1, solar distillation removed 99.97% salts and over 98% heavy metals. The high removal efficiency of 99.99% was achieved for Ca, Na, Mg, Mn, Ni, Se, Sr, and V. Organic characterization revealed that solar distillation removed over 83% aromatic compounds. Solar desalination using CAPER provides a low-cost and high-performance process to treat PW with high salinity and complex water chemistry for potential fit-for-purpose beneficial uses.

Effect of geographical origin on yield and composition of cone essential oils of Cedrus libani A. Rich. growing in Lebanese protected areas and variability assessment in comparison with literature survey.

Gas chromatography-mass spectrometry analysis together with principal component analysis revealed that geographical origin influenced the yield and composition of the essential oils (EOs) extracted by hydrodistillation performed for 3 h using a Clevenger-type apparatus, from the cones of Cedrus libani A. Rich., growing wild at four Lebanese natural reserves and protected areas: Bsharri, Chouf, Ehden, and Tannourine, and from a cultivated cedar growing in Qartaba. Essential oil chemical variability established between the different studied provenances suggested the involvement of abiotic factors such as geographical conditions, cultivation conditions, soil composition, and environmental factors in the chemical polymorphism of C. libani cones EOs. α-Pinene/ß-pinene characterized Ehden (ß-pinene 35.6%/α-pinene 27.7%), Chouf (α-pinene 37.3%/ß-pinene 26.1%), Bsharri (α-pinene 27.7%/ß-pinene 21.4%), and Tannourine (α-pinene 25.1%/ß-pinene 16.0%) samples, whereas Qartaba EO was distinguished by the dominance of myrcene (30.6%), α-pinene(26%), and limonene (14.1%). Comparison with the existing literature reinforced the chemical variability of C. libani EOs. This current study helped the estimation of a best harvest location for a good EO quality production, resource optimization, and pharmacological properties evaluation, according to the market demand.

Feasibility of concentrating textile wastewater using a hybrid forward osmosis-membrane distillation (FO-MD) process: Performance and economic evaluation.

The forward osmosis-membrane distillation (FO-MD) hybrid process has shown great promise in achieving zero liquid discharge in the textile industry, recovering valuable dye molecules while producing large amounts of clean water. However, the progress of this technology seems to have stagnated with the direct coupling of commercial asymmetric FO and MD membranes, because water management in the system is found to be rather complicated owing to the processing of the different membranes. Herein, we propose, for the first time, an FO-MD hybrid process using a custom-made self-standing and symmetric membrane and a hydrophobic polytetrafluoroethylene membrane in the FO and MD units, respectively. Three types of operation modes were investigated to systematically study the process performance in the concentration treatment of model textile wastewater; two commercial FO membranes were also tested for comparison. Owing to its low fouling propensity and lack of an internal concentration polarization effect, the water transfer rate of our symmetric FO membrane quickly reaches equilibrium with that in the MD unit, resulting in continuous and stable operation. Consequently, the hybrid process using the symmetric FO membrane was found to consume the least energy, as indicated by its lowest total cost in both lab- and large-scale systems. Overall, our study provides a new strategy for using a symmetric FO membrane in the FO-MD hybrid process and highlights its great potential for use in the treatment of textile wastewater.

Fungal biodegradation and multi-level toxicity assessment of vinasse from distillation of winemaking by-products.

The wastewaters from distilleries of winemaking by-products, a scarcely studied type of vinasse, were treated by white-rot fungal strains from species Irpex lacteus, Ganoderma resinaceum, Trametes versicolor, Phlebia rufa and Bjerkandera adusta. The main objectives of this study were to evaluate fungal performance during vinasse biodegradation, their enzyme patterns and ecotoxicity evolution throughout treatment. Despite all strains were able to promote strong (>80%) dephenolization and reduction of total organic carbon (TOC), P. rufa was less affected by vinasse toxicity and exhibit better decolorization. In batch cultures at 28 °C and pH 4.0, the first phase of P. rufa biodegradation kinetics was characterized by strong metabolic activity with simultaneous depletion of TOC, phenolics and sugars. The main events of second phase are the increase of peroxidases production after the peak of laccase activity, and strong color removal. At the end of treatment, it was observed highly significant (p < 0.001) abatement of pollution parameters (83-100% removal). Since water reclamation and reuse for e.g. crop irrigation is a priority issue, vinasse ecotoxicity was assessed with bioindicators representing three different phylogenetic and trophic levels: a marine bacterium (Aliivibrio fischeri), a freshwater microcrustacean (Daphnia magna) and a dicotyledonous macrophyte (Lepidium sativum). It was observed significant (p < 0.05) reduction of initial vinasse toxicity, as evaluated by these bioindicators, deserving special mention an almost complete phytotoxicity elimination.

Bacterial Cellulose production by K. saccharivorans BC1 strain using crude distillery effluent as cheap and cost effective nutrient medium.

Bacterial Cellulose (BC), a valuable biopolymer gaining importance over the past few decades due to its remarkable properties and applications. In this study, crude distillery effluent having a high COD value of 87,433 mg/L was used to produce Bacterial Cellulose under static fermentation by Komagataeibacter saccharivorans, a novel isolated bacterial strain. 1.24 g/L of cellulose production was noted after eight days along with 23.6% reduction in COD value. The BC pellicle was purified, lyophilized and stored. Further, the lyophilized BC pellicle was subjected to characterization techniques such as SEM, ATR-FTIR, XRD, NMR and TLC. Morphological analysis revealed that cellulose fibers were dense with higher porosity and an average fiber width of 60 nm. FTIR depicted similar functional groups as that of BC-HS medium. TLC of the biopolymer was performed to evaluate its purity. X-ray diffraction and 13C NMR studies gave more insights about the crystalline and the amorphous regions; the synthesized polymer exhibited 80.2% as crystallinity and crystallite size of 8.36. Hence, the present study demonstrates that distillery effluent waters could be effectively reused as production medium fulfilling two objectives namely one reducing COD and making the effluent safe for disposal and two to produce a value-added product.

Evaluation of concentration technologies in the design of biorefineries for the recovery of resources from vinasse.

This article reports a study of five designs of vinasse biorefineries that incorporate anaerobic bioreactors followed by a concentration technology such as evaporation, reverse osmosis, or forward osmosis. Different techniques of draw solution regeneration - evaporation, reverse osmosis, and membrane distillation - were also analyzed. Exergy analysis, a method that evaluates the resource conversion efficiency of systems, was used to compare the alternatives. The results indicated that among the alternatives analyzed, the combination of anaerobic digestion and reverse osmosis presented the highest exergy efficiency (62%). However, evaporators were the most feasible in terms of costs. Both alternatives are interesting and the final choice depends on the technology available and local economy. In any case, the treatment of 491.76 m3/h of vinasse (exergy rate of 60513.8 kW) to recover 70% of water could reduce external water requirement by 66% and generate 28% additional electricity for the sugarcane plant. In this case, the water recovery could represent an economy of 8,490,435.76 USD/year for the Brazilian alcohol industry.