Pilot-scale System Research Articles

Algal odorous risk assessments in pilot-scale drinking water distribution system (DWDS): Risk occurrence, influencing factors and degradation patterns

Tap water quality is at risk for odor-producing algae. Besides being hazardous to source water and water treatments, these algae threaten drinking water distribution system (DWDS). Yet little information is available for odorous risks occurring, responding, and transforming in real DWDS. Hence, two algae (Microcystis aeruginosa, MA; Pseudanabaena sp., PS) were selected for pilot studies. Two ways were verified for algal occurrence, including insufficient water treatments and DWDS-biofilm attachment. MA survived moderate disinfectant exposures and restored odorants (β-cyclocitral). Also, MA could be attached to biofilm and its detachment occurred upon flushing (0.60 m/s). These occurrence ways were not seen for PS. Three factors were compared for living algae in DWDS. Flow velocities had minimal impacts on MA but affected PS odorant (2-methylisobropanol, 2-MIB) releases. Releasing rates increased by 115.79% with velocity from 0.05 m/s to 1.50 m/s. Disinfectants were the riskiest, maximizing risks for MA and PS, respectively at 0.30 mg/L NH2Cl and 1.00 mg/L Cl2. Coexisting antibiotics showed selective effects and reduced risks, e.g., tetracycline reduced MA intensity and PS odorant production. For naked odorant transformation, 2-MIB in DWDS had reduced degradation ratios compared to beaker conditions. Overall, odorous risks by MA and PS were different. MA was tough and could resist water treatments and adverse stressors in DWDS, with partial odorants remaining within cells. PS was vulnerable to treatments and DWDS, and the released odorants were not degradable. Hence, customized management is required for various algal odorous problems in DWDS.

Innovative ceramic membrane plate filtration system for sustainable semiconductor industry wastewater treatment: A pilot scale study

Conventional methods of coagulation and flocculation are used to treat semiconductor industry wastewater, but they often fail to recover valuable silica particles and result in resource wastage and environmental risks. Despite the potential of membrane filtration for silica recovery, limited research is available on scaling up the process beyond laboratory scale. Therefore, this study aims to develop and evaluate the feasibility of pilot-scale ceramic membrane plate filtration system for treatment of diluted back grinding wastewater (DBGW) from the semiconductor industry. Specific objectives include assessing permeate quality in terms of rejection and benchmarking it to established standards, identifying fouling mechanisms, characterising sludge constituents and conducting life cycle assessment (LCA) to evaluate the environmental impacts of the ceramic membrane plate filtration system compared with conventional treatment. The pilot membrane plate filtration system demonstrated significant reductions of 85.71 % in chemical oxygen demand, 67.31 % in total suspended solid, 75 % in nitrate–nitrogen (NO3-N), 33.33 % in ammonia nitrogen (NH3-N), 74.07 % in colour and 98.37 % in turbidity. Effective mitigation of irreversible fouling during DBGW filtration was achieved using 0.1 M NaOCl, resulting in a flux recovery ratio of 95.35 %. The retained silica on the membrane exhibited a purity of 64 wt%, as confirmed by EDX analysis. The treated wastewater met various regulatory standards including Malaysia Industrial Effluent Discharge (Standard A and Standard B), restricted USEPA standard, NWQS Class IIA, IIB, III, IV and V, and Singapore’s greywater standards. The fouling mechanism of silica on the ceramic membrane was well represented by the standard blocking model with an R2 value of 0.92. Furthermore, LCA confirmed that the utilisation of the ceramic membrane plate filtration system exhibited fewer environmental impacts than conventional coagulation–flocculation methods. This study represents a significant breakthrough in wastewater treatment in the semiconductor industry in terms of concurrent recovery and reuse of silica to address environmental and resource sustainability concerns.

Recycling food waste to agriculture through hydrothermal carbonization sustains food-energy-water nexus

Recycling underutilized resources from food waste (FW) to agriculture through hydrothermal carbonization (HTC) has been proposed to promote a circular economy (CE) in food-energy-water (FEW) nexus. However, most HTC studies on FW were conducted at laboratory scale, and little is known on the efficacy and feasibility of field application of HTC products from FW, i.e. the aqueous phrase (AP) and solid hydrochar (HC), to support agriculture production. An integrated pilot-scale HTC system was established to investigate practical HTC reaction conditions treating FW. A peak temperature of 180 °C at a residence time of 60 min with 3 times AP recirculation were recommended as optimal HTC conditions to achieve efficient recovery of nutrients, and desirable AP and HC properties for agriculture application. Dilution of the raw AP and composting of the fresh HC are necessary as post-treatments to eliminate potential phytotoxicity. Applying properly diluted AP and the composted HC significantly improved plant growth and nutrient availability in both greenhouse and field trials, which were comparable to commercial chemical fertilizer and soil amendment. The HTC of FW followed with agricultural application of the products yielded net negative carbon emission of −0.28 t CO2e t−1, which was much lower than the other alternatives of FW treatments. Economic profit could be potentially achieved by valorization of the AP as liquid fertilizer and HC as soil amendment. Our study provides solid evidences demonstrating the technical and economic feasibility of recycling FW to agriculture through HTC as a promising CE strategy to sustain the FEW nexus.

Experimental investigation on the preparation of macroscopic 0–1 mm powdered coal by a vertical spindle mill

The vertical spindle mill (VSM) is the key equipment to realize the preparation of 0–1 mm fuel used in powdered-coal-fired circulating fluidized bed combustion technology (PC-CFB). In this paper, a pilot-scale VSM test system was set up to explore the feasibility and operating performance of coarse-grained pulverized coal preparation. The effects of loading force, table revolution rate, and ventilation rate on the product size distribution, as well as the energy consumption of the grinding process were emphatically discussed. The results show that the product size of VSM increases with the decrease of loading force and the increase of ventilation rate, but too small a loading force will affect the normal output of VSM. Additionally, the product size of VSM decreases firstly and then increases with the increase of table revolution rate. Further, the energy consumption of the powdered coal preparation process was quantitatively described, and a semi-empirical model of comminution energy based on the powdered coal particle size distribution was proposed and verified by the measured values with an average accuracy of ±30 %. This model can estimate the power consumption of the mill, which can be used as an input parameter of the heat balance calculation model for the PC-CFB pulverizing system.

The Effects of Different Combinations of Cattle Organic Soil Amendments and Copper on Lettuce (cv. Rufus) Plant Growth

In modern agricultural production, cattle manure waste recovery is considered as a sustainable approach to agricultural waste management, reducing environmental pollution and chemical fertilizer use. This study aimed to investigate the effects of manure and digestate derived from a pilot-scale livestock waste-recycling system, in combination with a low copper concentration as a fungicide, on the physiological response of lettuce cv Rufus (Lactuca sativa L.) plants and the associated soil microbiome. A five-week microcosm experiment was conducted in a greenhouse under environmental conditions. Lettuce plant performance was assessed in terms of biomass, leaf area index, photosynthetic activity, chlorophyll measurements, lipid peroxidation, total phenolic content, and nutrient uptake. The results suggested that incorporating digestate into the potting soil mix significantly enhanced crop yields compared to the control and manure treatments. The soil microbial activity increased in the presence of fertilizers, improving the soil chemical and biological properties. The addition of copper negatively affected the growth and physiological performance of the lettuce plants under both the control and manure-treated conditions, except for those grown in the presence of digestate, where copper accumulation was reduced. These findings highlight the potential of growing horticultural crops using organic fertilization through livestock waste anaerobic digestate, establishing a waste-to-food recycling system.

Polluted River Water Treatment Via Pilot-Scale Membrane Photocatalytic Reactor (MPR) Incorporated Zno-Kaolin Under Different Light Intensity

Polluted river water treatment utilizes a mix of physical, chemical, and biological processes and activities. Conventional systems, including coagulation, flocculation, sedimentation, filtration, and disinfection, have several limitations. Hence, the Membrane Photocatalytic Reactor (MPR) is one of the most promising methods for polluted river water treatment. ZnO-Kaolin nanoparticles served as great photocatalysts for MPR performance. This study focuses on the pilot-scale hybrid MPR treatment of polluted river water under different light intensities (100, 125, and 225 watts) and irradiation times (20, 30, and 40 minutes). The treated water quality analysis is based on the Environmental Quality Act 1974 (EQA 1974). The kinetic rate was also investigated using pseudo-first-order and pseudo-second-order models. It was found that 225 watts and 30 minutes were the optimum values. The pilot scale hybrid MPR proved to fit well with the pseudo-second-order kinetic models, suggesting that the degradation follows a chemisorption mechanism. In conclusion, we believe the hybrid MPR pilot-scale system will enhance efficiency in cleaning dirty river water, all while meeting the standards of the EQA 1974.

Microbial osmotic pressure desalination system for desulfurization wastewater from coal-fired power plants: A pilot study

The treatment of desulfurization wastewater has emerged as a critical area of research due to the significant water consumption and drainage volume associated with thermal power plants, which account for 30 %–40 % of industrial water usage. The desalination and treatment of this wastewater generate desulfurization byproducts, posing environmental risks and incurring high operational costs. This study established a pilot-scale desalination system based on the principle of microbial osmotic pressure for the treatment of desulfurization wastewater from power plants. The desulfurization wastewater primarily contains Cl−, SO42−, Mg2+, Ca2+, and Na+ ions. The microbial osmotic pressure device reduced the water conductivity from 26,000 μs/cm to below 8000 μs/cm, achieving a total salt removal rate of 70 %. The removal rates for Cl−, SO42−, Mg2+, Ca2+ and Na+ were 69.10 %, 76.55 %, 73.0 %, 35.34 % and 52.80 %, respectively. The desalinated water from the osmotic pressure device then undergoes aerobic removal of organic compounds, followed by membrane filtration and reverse osmosis for further desalination. The effluent conductivity is <1000 μs/cm, meeting the standards for reuse water. The microbial osmotic pressure device enriched salt-absorbing halobacteria and was dominated by norank_f__Bacteroidetes_vadinHA17, Trichococcus, Acidovorax, Soehngenia, and norank_f__Hungateiclostridiaceae. Compared to traditional processes, the biological desalination process demonstrates lower operational and annual maintenance costs under conditions of regular addition of microbial agents and liquid activators to sustain the desalination bacterial community. Future research could focus on desalination microbial cultivation methods to improve stability and reduce costs.

Pilot scale demonstration of an underground biological aerated filter for rural wastewater treatment in a protected area

The availability of land is one of the advantages of rural wastewater treatment. However, this advantage may be absent in protected areas. The objective of this study is to showcase pilot-scale wastewater treatment approaches specifically tailored to address challenges presented by these unique circumstances. The demonstration case presented here involves a rural campsite where ground works are restricted. A pilot-scale decentralized system that includes a rainwater recycling system for potable water production (2–3 m3/d) and an underground biological aerated filter for wastewater treatment was installed. The biological aerated filter was built under a parking area (a so-called Phytoparking® system) and did as such not use additional ground surface. The Phytoparking with an area of 44 m2 was operated for 7 months and a total of 220 m3 grey water and 127 m3 black water was treated. Good pollutants removal efficiency was achieved for total suspended solids (93 %), COD (93 %), NH4+-N (93 %), TP (99 %), E.coli (log reduction 4.3) and total coliforms (log reduction 2.4). The potential wastewater reuse is not only about technological concern but also social acceptable concern. Therefore, the campsite customers' acceptance level of this system and the reused water were surveyed by a questionnaire. Based on the results of the study's pollutant removal efficiency and questionnaire responses, it can be concluded that local and/or decentralized water treatment and reuse systems were perceived positively.

Hydraulic characterization of a hybrid aerated vertical and horizontal treatment wetland

Characterizing the performance of any treatment wetland (TW) system requires a fundamental understanding of the hydraulic behavior of the system. In aerated treatment, the air supply increases complexity, and the internal behavior of TWs can vary according to the adopted aeration strategy. Understanding these changes can provide insights into an optimized operation for aerated TWs. In this sense, the present work characterizes the hydraulics of a hybrid vertical and horizontal aerated TW through parallel tracer testing under different aeration strategies (varying aeration duration and aeration between the different compartments). The tracer test was conducted using amino-G acid and salt on a pilot scale system and measured at the outlet and inside the system. These results are subsequently compared to a full-scale system of a similar design to assess the validity of the results on a larger scale. The results allowed a characterization of actual retention time, the estimated number of tanks-in-series (NTIS), the volume of dead zones, and the identification of the hydraulic behavior under different aeration conditions. The results indicated that decreasing aeration duration led to more heterogeneity within the filter, the aeration on the primary filter plays an important role in mixing, and the pilot scale results can be upscaled for a larger scale. It also highlighted the impact of aeration in the different compartments of this hybrid aerated wetland system, which can contribute to an accurate characterization of specific pollutant removal kinetics.

Pilot-scale electrochemical advanced oxidation (EAOP) system for the treatment of Ni-EDTA-containing wastewater

Electrochemical advanced oxidation processes (EAOP) have shown great potential for the abatement of complexed heavy metals, such as metal-EDTA complexes, in recent studies. While removal of metal-EDTA complexes has been extensively examined in bench-scale reactors, much less attention has been given to the efficacy of this process at larger scale. In this study, we utilize a 72 L pilot-scale continuous flow system comprised of six serpentine flow channels and 90 pairs of flow-through electrodes for the degradation of Ni-EDTA complexes and removal of Ni from solution. The influence of a range of key operating parameters including flow rate, current density and initial Ni-EDTA concentration on rate and extent of Ni-EDTA degradation and Ni removal were examined. Our results showed that at a feed flow rate of 36 L h−1, current density of 5 mA cm−2 and initial Ni-EDTA concentration of 1 mM, the pilot-scale system achieved 74 % total Ni removal, 78 % total EDTA removal and 40 % TOC removal with energy consumption of 13.6 kWh m−3 order−1 and energy efficiency of 7.9 g kWh−1 for total Ni removal. A mechanistically-based kinetic model, which was developed in our previous bench-scale study, provides a satisfactory description of the experimental results obtained in the pilot-scale unit. Long term operation of the pilot-scale unit resulted in corrosion of PbO2 anode along with inorganic scaling as well as organic fouling on the PbO2 surface resulting in an obvious decline in Ni-EDTA degradation. Overall, the results of this study suggest that large scale anodic oxidation of wastewaters containing metal-organic complexes is an effective means of degrading organic ligands thereby enabling removal of the metal at the cathode. However, additional efforts are required to enhance the durability of the anode material and reduce material costs and energy consumption.

Low-cost scalable high-power-density solar thermochemical energy storage via accelerating ion diffusion in Calcium-based solid wastes

Calcium-based solar thermochemical energy storage (TCES) has a great potential for next-generation concentrated solar power (CSP) systems due to its unique advantages of high operation temperature from 750 ℃ to 900 ℃ and high energy storage density, while current Calcium-based pellets suffer from poor cyclic stability and slow reaction kinetics. The mainstream solution relies on expensive inert stabilizers and complicated fabrication processes, which severely limited their affordability and scalability. Herein, we propose a strategy for recycling different Ca-based solid wastes, achieving low-cost and scalable high-power-density solar TCES simultaneously via the synergistic effect of multiple solid wastes and MgCl2. The power density of proposed pellets is 2 times than that of the conventional CaCO3, as the promoted solid-state diffusion of Ca2+ accelerates the decomposition of CaCO3. The energy storage density is as high as 1191 kJ/kg after 50 cycles, along with energy storage economy higher than 70 MJ/$ and friction loss less than 0.3 %, far exceeding that of the state-of-the-art Calcium-based TCES pellets. The feasibility of high-performance solar-driven TCES is further demonstrated on a pilot-scale system, providing a promising high-temperature thermal energy storage solution for next-generation CSP techniques.

Biological fermentation pilot-scale systems and evaluation for commercial viability towards sustainable biohydrogen production

Featuring high caloric value, clean-burning, and renewability, hydrogen is a fuel believed to be able to change energy structure worldwide. Biohydrogen production technologies effectively utilize waste biomass resources and produce high-purity hydrogen. Improvements have been made in the biohydrogen production process in recent years. However, there is a lack of operational data and sustainability analysis from pilot plants to provide a reference for commercial operations. In this report, based on spectrum coupling, thermal effect, and multiphase flow properties of hydrogen production, continuous pilot-scale biohydrogen production systems (dark and photo-fermentation) are established as a research subject. Then, pilot-scale hydrogen production systems are assessed in terms of sustainability. The system being evaluated, consumes 171,530 MJ of energy and emits 9.37 t of CO2 eq when producing 1 t H2, and has a payback period of 6.86 years. Our analysis also suggests future pathways towards effective biohydrogen production technology development and real-world implementation.

Riboflavin modified carbon cloth enhances anaerobic digestion treating food waste in a pilot-scale system.

Previous laboratory-scale studies have consistently shown that carbon-based conductive materials can notably improve the anaerobic digestion of food waste, typically employing reactors with regular capacity of 1-20L. Furthermore, incorporating riboflavin-loaded conductive materials can further address the imbalance between fermentation and methanogenesis in anaerobic systems. However, there have been few reports on pilot-scale investigation. In this study, a 10m2 of riboflavin modified carbon cloth was incorporated into a pilot-scale (2m3) food waste anaerobic reactor to improve its treatment efficiency. The study found that the addition of riboflavin-loaded carbon cloth can increase the maximum organic loading rate (OLR) by 40% of the pilot-scale reactor, compared to the system using carbon cloth without riboflavin loading, while ensuring efficient operation of the reaction system, effectively alleviating system acidification, sustaining methanogen activity, and increasing daily methane production by 25%. Analysis of the microbial community structure revealed that riboflavin-loaded carbon cloth enriched the methanogenic archaea in the genera of Methanothrix and Methanobacterium, which are capable of extracellular direct interspecies electron transfer (DIET). And metabolic pathway analysis identified the methane production pathway, highly enriched on the reduction of acetic acid and CO2 at riboflavin-loaded carbon cloth sample. The expression levels of genes related to methane production via DIET pathway were also significantly upregulated. These results can provide important guidance for the practical application of food waste anaerobic digestion engineering.

Sorting Out the Latest Advances in Separators and Pilot-Scale Microbial Electrochemical Systems for Wastewater Treatment: Concomitant Development, Practical Application, and Future Perspective.

To date, dozens of pilot-scale microbial fuel cell (MFC) devices have been successfully developed worldwide for treating various types of wastewater. The availability and configurations of separators are determining factors for the economic feasibility, efficiency, sustainability, and operability of these devices. Thus, the concomitant advances between the separators and pilot-scale MFC configurations deserve further clarification. The analysis of separator configurations has shown that their evolution proceeds as follows: from ion-selective to ion-non-selective, from nonpermeable to permeable, and from abiotic to biotic. Meanwhile, their cost is decreasing and their availability is increasing. Notably, the novel MFCs configured with biotic separators are superior to those configured with abiotic separators in terms of wastewater treatment efficiency and capital cost. Herein, a highly comprehensive review of pilot-scale MFCs (>100 L) has been conducted, and we conclude that the intensive stack of the liquid cathode configuration is more advantageous when wastewater treatment is the highest priority. The use of permeable biotic separators ensures hydrodynamic continuity within the MFCs and simplifies reactor configuration and operation. In addition, a systemic comparison is conducted between pilot-scale MFC devices and conventional decentralized wastewater treatment processes. MFCs showed comparable cost, higher efficiency, long-term stability, and significant superiority in carbon emission reduction. The development of separators has greatly contributed to the availability and usability of MFCs, which will play an important role in various wastewater treatment scenarios in the future.

An attempt to augment performance of machine learning models in a pilot-scale urban wastewater treatment system

The challenge we face is striking a balance between ensuring the standards for wastewater treatment processes and minimizing energy consumption. As such, accurate predictive models become critical. With machine learning algorithms having the ability to discern relationships between inputs and outputs, broad interest has been shown in their applications in wastewater treatment. A key research focus is on effectively adjusting these generic machine learning algorithms to adapt to frequent fluctuations of water quality, inflow volume, and environmental variations. This study developed a Nonlinear Autoregressive neural network (NARX) model having an adaptive real-time updating module to predict the ammonium concentration in the treated effluent. The model has exhibited high predictive accuracy on the testing data, achieving an R2 value of 0.997. By incorporating an adaptive real-time updating module, the model's capability to predict effluent ammonium concentration on novel data sets has been significantly improved, with the R2 value for these predictions increasing from an initial 0.918 to a more refined range of 0.966 to 0.984. Our findings confirm that integrating real-time updating capabilities with machine learning algorithms substantially improves the stability and predictive performance of the models. These outcomes will prompt a broader integration of artificial intelligence in the domain of environmental engineering, which shall foster the implementation of more accurate and eco-friendly wastewater treatment strategies.

Research on a Biofilter for a Typical Application Scenario in China: Treatment of Pesticide Residue Wastewater in Orchards

To reduce pesticide pollution and promote sustainable agricultural development in China, we designed a pilot-scale biofilter system to treat residual imidacloprid wastewater in an orchard. The biofilter system demonstrated a high rate of removal of imidacloprid from the biodegradation wastewater, with removal rates from the outlet exceeding 99% at different concentrations of pesticides. Among environmental factors, imidacloprid concentration at the inlet and biomixture significantly affected the activity of imidacloprid-degrading bacteria. The dominant microbial communities during the stable operation of the biofilter system included Firmicutes, Actinobacteria, Proteobacteria, and Bacteroidetes at the phylum level and Bacillus, Methylobacter, and unclassified_f__Microbacteriaceae at the genus level. In future initiatives to improve biofilter performance and applicability, increasing attention should be paid to the dominant microbial communities, the number of biofilter units, and important environmental factors. Orchard workers in China should improve the existing treatment of residual pesticide wastewater to mitigate agricultural non-point source pollution.

Comparative Analysis of Donnan Steric Partitioning Pore Model and Dielectric Exclusion Applied to the Fractionation of Aqueous Saline Solutions through Nanofiltration

The aim of this study was to analyze, both theoretically and experimentally, the material transport mechanisms governing the separation of ionic species in aqueous solutions using nanofiltration membranes. To interpret the experimental results, the Donnan Steric Partitioning Model (DSPM) and the Dielectric Exclusion Model (DSPM-DE) were applied and computationally simulated in Matlab. Experimental tests were conducted using a pilot-scale system with commercial NF90 membranes. The results indicate that the DSPM better describes the rejection of monovalent ions (sodium and chloride), while the DSPM-DE is more suitable for divalent ions (sulfate and magnesium). Additionally, both models were sensitized to explore the impact of hindrance factors on the rejection of different ionic species. For neutral molecules present in the solution, it was observed that the DSPM and DSPM-DE do not adequately interpret selectivity, suggesting that under such conditions, the electrostatic exclusion mechanism loses significance, with the steric mechanism prevailing.

Operation and Performance of The Lab and Pilotscale Greywater Treatment Systems: Biochar and Gravel Use in South Africa

Water security in South Africa depends on natural and artificial water sources such as rivers, lakes, rainwater harvesting, boreholes, dams, desalination, the importation of water from nearby countries, and wastewater treatment plants. The primary input to these water resources is rainfall which is estimated to be around 492 mm per year and is half of the world average (985 mm per year) due to climate change impacts. This study encourages the treatment and reuse of greywater as an additional water source for non-potable purposes such as toilet flushing and irrigation. The performance of the Laboratory (Lab)-scale Gravel Filter Towers (GFTs) was evaluated concurrently with the Pilot-scale system for remediation of the microbiological and physicochemical constituents in greywater which was sampled from separate single-households for both systems. The highest removal efficiency of faecal coliforms by the GTFs was 92.89 ± 93.39 % while the Pilot-scale exhibited a removal efficiency of 21.51 ± 12.47 %. The systems showed partial removal of microbiological, chemical, nutrient, and physical constituents, indicating that further analysis and improvements are required before decentralization. The GFTs could be improved by the addition of a biochar filter while the pilot-scale systems require fresh treatment materials monthly to avoid clogging and leaching of biofilms to the final collection tank. Further analysis could involve the profiling of the microbial communities using metagenomic techniques which may provide insight into the biochemical functioning (bioremediation, quorum sensing, and pathogenicity) of the system.

Biogas Upgrading Using a Single-Membrane System: A Review.

In recent years, the use of biogas as a natural gas substitute has gained great attention. Typically, in addition to methane (CH4), biogas contains carbon dioxide (CO2), as well as small amounts of impurities, e.g., hydrogen sulfide (H2S), nitrogen (N2), oxygen (O2) and volatile organic compounds (VOCs). One of the latest trends in biogas purification is the application of membrane processes. However, literature reports are ambiguous regarding the specific requirement for biogas pretreatment prior to its upgrading using membranes. Therefore, the main aim of the present study was to comprehensively examine and discuss the most recent achievements in the use of single-membrane separation units for biogas upgrading. Performing a literature review allowed to indicate that, in recent years, considerable progress has been made on the use of polymeric membranes for this purpose. For instance, it has been documented that the application of thin-film composite (TFC) membranes with a swollen polyamide (PA) layer ensures the successful upgrading of raw biogas and eliminates the need for its pretreatment. The importance of the performed literature review is the inference drawn that biogas enrichment performed in a single step allows to obtain upgraded biogas that could be employed for household uses. Nevertheless, this solution may not be sufficient for obtaining high-purity gas at high recovery efficiency. Hence, in order to obtain biogas that could be used for applications designed for natural gas, a membrane cascade may be required. Moreover, it has been documented that a significant number of experimental studies have been focused on the upgrading of synthetic biogas; meanwhile, the data on the raw biogas are very limited. In addition, it has been noted that, although ceramic membranes demonstrate several advantages, experimental studies on their applications in single-membrane systems have been neglected. Summarizing the literature data, it can be concluded that, in order to thoroughly evaluate the presented issue, the long-term experimental studies on the upgrading of raw biogas with the use of polymeric and ceramic membranes in pilot-scale systems are required. The presented literature review has practical implications as it would be beneficial in supporting the development of membrane processes used for biogas upgrading.

Energetic Comparison of Flow-Electrode Capacitive Deionization and Membrane Technology: Assessment on Applicability in Desalination Fields.

Flow-electrode capacitive deionization (FCDI) is a promising technology for sustainable water treatment. However, studies on the process have thus far been limited to lab-scale conditions and select fields of application. Such limitation is induced by several shortcomings, one of which is the absence of a comprehensive process model that accurately predicts the operational performance and the energy consumption of FCDI. In this study, a simulation model is newly proposed with initial validation based on experimental data and is then utilized to elucidate the performance and the specific energy consumption (SEC) of FCDI under multiple source water conditions ranging from near-groundwater to high salinity brine. Further, simulated pilot-scale FCDI system was compared with actual brackish water reverse osmosis (BWRO) and seawater reverse osmosis (SWRO) plant data with regard to SEC to determine the feasibility of FCDI as an alternative to the conventional membrane processes. Analysis showed that FCDI is competent for operation against brackish water solutions under all possible operational conditions with respect to the BWRO. Moreover, its distinction can be extended to the SWRO for seawater conditions through optimization of its total effective membrane area via scale-up. Accordingly, future directions for the advancement of FCDI was suggested to ultimately prompt the commercialization of the FCDI process.