Microbial Desalination Cell Research Articles

Performance of Exoelectrogenic Bacteria Used in Microbial Desalination Cell Technology.

The tri-functional purpose of Microbial Desalination Cell (MDC) has shown a great promise in our current scarcity of water, an increase in water pollution and the high cost of electricity production. As a biological system, the baseline force that drives its performance is the presence of exoelectrogens in the anode chamber. Their presence in the anodic chamber of MDC systems enables the treatment of water, desalination of seawater, and the production of electrical energy. This study reviews the characteristics of exoelectrogens, as a driving force in MDC and examines factors which influence their growth and the performance efficiency of MDC systems. It also addresses the efficiency of mixed cultures with certain predominant species as compared to pure cultures used in MDC systems. Furthermore, the study suggests the need to genetically modify certain predominant strains in mixed cultures to enhance their performance in COD removal, desalination and power output and the integration of MDC with other technologies for cost-effective processes.

Anoxic-biocathode microbial desalination cell as a new approach for wastewater remediation and clean water production.

Bioelectrochemical systems are emerging as a promising and friendly alternative to convert the energy stored in wastewater directly into electricity by microorganisms and utilize it in situ to drive desalination. To better understand such processes, we propose the development of an anoxic biocathode microbial desalination Cell for the conversion of carbon- and nitrogen-rich wastewaters into bioenergy and to perform salt removal. Our results demonstrate a power output of 0.425 W m-3 with desalination, organic matter removal and nitrate conversion efficiencies of 43.69, 99.85 and 92.11% respectively. Microbiological analysis revealed Proteobacteria as the dominant phylum in the anode (88.45%) and biocathode (97.13%). While a relatively higher bacterial abundance was developed in the anode chamber, the biocathode showed a greater variety of microorganisms, with a predominance of Paracoccus (73.2%), which are related to the denitrification process. These findings are promising and provide new opportunities for the development and application of this technology in the field of wastewater treatment to produce cleaner water and conserve natural resources.

Construction and application of a 1-liter upflow-stacked microbial desalination cell

As increasing demand of global reuse water, microbial desalination cell (MDC) is developed as a potential desalination approach to drive ion migration and separation through biodegradation without any additional energy. A novel, efficient, stable reactor coupled stacked MDC with upflow MDC was constructed, which was named as upflow-stacked MDC (USMDC). Compared with the traditional stacked MDC and upflow MDC, the desalination and generation performance of the USMDC was evaluated. Results showed that, after 24 h, the desalination ratio of USMDC can reach 91.9% when the external resistance was 1.5 Ω, which was 1.18 and 1.48 times higher than SMDC and UMDC, respectively. The long-term performance of the desalination efficiency was tested, which was maintained at 87.2–96.0% and stable for consecutive 120 days. Then, it was also the investigated that the relationship between desalination rate and external resistance during every period. The USMDC produced a maximum power density of 32.91 W m−3. In addition, the difference of current density between USMDC and SMDC indicates the turbulence generated by cylindrical structure could effectively decrease the internal resistance. It was also corroborated that salt concentration gradient and bipolar electrodialysis would decline the charge transfer efficiency. Accordingly, USMDC was verified having the superior desalination performance thus providing the possibility for application in wastewater reuse.

Simultaneous bioelectricity generation, desalination, organics degradation, and nitrogen removal in air–cathode microbial desalination cells

In this study, a three-chamber air–cathode microbial desalination cell (AMDC) was constructed using activated sludge as the inoculating microbial source and carbon cloth as the electrode. The simultaneous bioelectricity generation, desalination, degradation of organic compounds, and nitrogen removal in the AMDC having different electrode spacings (16, 12, and 8 cm) provided an insight into the microbial community. The experimental results showed that with a gradual decrease in the electrode spacing, electricity production and desalination performance first increased and then decreased. While AMDC1 with 16 cm electrode spacing became active faster than other cells and reached a peak voltage of 598 mV on the tenth day, AMDC2 with 12 cm electrode spacing showed the best start-up performance with a maximum output voltage of 645 mV, maximum power density of 214.7 mW/m3, and minimum resistance of 516.9 Ω. AMDC3 with 8 cm electrode spacing reached a peak voltage of 598 mV, which was between those of AMDC1 and AMDC2. The three AMDCs were run until the end of the cycle, and there was no significant difference in their ammonium removal rate and chemical oxygen demand. For AMDC1–3, the desalination rates were 84.86%, 87.71%, and 83.43%, and the Coulomb efficiencies were 17.29%, 18.60%, and 17.95%, respectively. Further, scanning electron microscopy showed that a large number of microorganisms could attach to the surface of the anode carbon cloth electrode; 16S rRNA sequencing showed that the typical electrogenic microbial communities were Bacillus (11.6%) and Arcobacter (9.6%). As the poor performance of the AMDC was primarily due to a lack of electrogenic microorganisms in the active function of the anode chamber, screening the functional microorganisms provided a reference for optimizing and amplifying the application of microbial desalination cells in practical research.

Using C. vulgaris assisted microbial desalination cell as a green technology in landfill leachate pre-treatment: a factor-performance relation study

Abstract Algae biocathodes have become one of the most sustainable replacements for abiotic cathodes which were expensive and had toxic chemical oxidant by-products. In this study, a pure culture of Chlorella vulgaris from a photobioreactor was pumped into a photosynthetic microbial desalination cell to treat real landfill leachate (had undergone physical treatment) under varying ‘factor-conditions (FC)’ to embark on a factor-performance relation (FPR) study. This aimed at determining the relationship between operating factors and to depict the most favourable conditions (and range) in order to boost the overall performance of the reactor/cell. Three groups of FC (A, B and C) were adapted, in that, under FC A external resistance was varied, FC B varied pumping rate and FC C varied temperature, light intensity and dissolved oxygen under conditions flow and recirculation mode. Results showed 95% chemical oxygen demand (COD) removal, a maximum power density of 121.57 mWm−2 (anodic volume) and an average desalination rate of 3.93 mg/L/h. The varying results at different FC showed the significant impact of operating conditions on performance. Algae biocathodes also proved to be an essential benefit in boosting the sustainable application of microbial desalination cells (MDCs) in wastewater and landfill pre-treatment as well as the generation of bioenergy.

Comparative Performance of Microbial Desalination Cells Using Air Diffusion and Liquid Cathode Reactions: Study of the Salt Removal and Desalination Efficiency

Microbial Desalination Cell (MDC) represents an innovative technology which accomplishes simultaneous desalination and wastewater treatment without external energy input. MDC technology could be employed to provide freshwater with low-energy input, for example, in remote areas where organic wastes (i.e. urban or industrial) are available. In addition, MDC technology has been proposed as pre-treatment in conventional reverse osmosis plants, with the aim of saving energy and avoiding greenhouse gases related to conventional desalination processes. The use of oxygen reduction (i.e. O2 + 2H2O +4e-  4 OH-, E0’ = 0.815 V, pH=7) was usually implemented as cathodic reaction in most of the MDCs reported in literature, whereas other strategies based on liquid catholytes have been also proposed, for example, ferro-ferricyanide redox couple (i.e. Fe(CN)63- + 1e-  Fe(CN)64-, E0 = 0.37 V). As the MDC designs in the literature and operation modes (i.e. batch, continuous, semi-continuous, etc.) are quite different, the available MDC studies are not directly comparable. For this reason, the main objective of this work was to have a proper comparison of two similar MDCs operating with two different catholyte strategies, and compare performance and desalination efficiencies. In this sense, this study compares the desalination performance of two laboratory-scale MDCs located in two different locations for brackish water and sea water using two different strategies. The first strategy consisted of an air cathode for efficient oxygen reduction, while the second strategy was based on a liquid catholyte with Fe3+/Fe2+ solution (i.e. ferro-ferricyanide complex). Both strategies achieved desalination efficiency above 90% for brackish water. Nominal desalination rates (NDR) were in the range of 0.17-0.14 L·m-2·h-1 for brackish and seawater with air diffusion cathode MDC, respectively, and 1.5-0.7 L·m-2·h-1 when using ferro-ferricyanide redox MDC. Organic matter present in wastewater was effectively removed at 0.9 and 1.1 kg COD·m-3·day-1 using the air diffusion cathode MDC for brackish and sea water, respectively, and 7.1 and 19.7 kg COD·m-3·day-1 with a ferro-ferricyanide redox MDC. Both approaches used a laboratory MDC prototype without any energy supply (excluding pumping energy). Pros and cons of both strategies are discussed for subsequent upscaling of MDC technology.

New insights into the application of microbial desalination cells for desalination and bioelectricity generation

Microbial desalination cell (MDC) is considered as a cost-effective substitution to the present energy-intensive desalination methods. Transfer of salt ions through ion exchange membranes towards the counter electrodes takes place through the utilization of self-generated bioelectricity and the concentration gradient. Ions transportation is one of the main challenges faced in MDCs to which less attention has been paid during the course of development. Therefore, new insights into the application of MDCs for efficient utilization of the generated bioelectricity for desalination are of high demand. In light of this, the present research thoroughly investigated the behavior of ions transportation and bioelectricity generation in three MDCs using three different salt solutions; NaCl, synthetic and artificial seawater. The findings obtained suggested that the efficiency of ions transportation and fouling behavior were influenced by salt compositions and concentration of the salt solution. Multivalent ions (i.e. Mg2+, Ca2+, and PO43-) were found more prone to precipitation on the CEM forming a scaling layer, whereas, inorganic deposition and biofouling development were more likely to happen on the AEM. This study also confirmed the occurrence of a significant back diffusion of K+ from catholyte into desalination chamber. Such back diffusion could limit the use of potassium buffer in catholyte in real-scale applications. Moreover, the coefficients of salt transfer and ion diffusion were calculated using mathematical model and Excel solver in three running MDCs. Low salt transfer and ion diffusion coefficients values obtained for all three MDCs could explain the general low performance of MDCs. Further studies are required to optimize the salt transfer and ion diffusion coefficients to boost MDC performance in general; affecting their real-scale implementation.

Photosynthetic Microbial Desalination Cell to Treat Oily Wastewater Using Microalgae Chlorella Vulgaris

Microbial desalination cell (MDC) offers a new and sustainable approach to desalinate saltwater by directly utilizing the electrical power generated by bacteria during organic matter oxidation. In this study, we used microalgae Chlorella Vulgaris in the cathode chamber to produce oxygen as an electron accepter by photosynthesis process for generate bioelectricity power and treat oil refinery wastewater by microorganisms in both anode and cathode.The power density generated by this Photosynthetic Microbial Desalination Cell (PMDC) with 1KΩ external resistance at the first 4th hr. of operation period was 0.678 W/m3 of anode volume and 0.63 W/m3 of cathode volume. It increased after one day to a peak value of (4.32 W/m3 of anode volume and 4.013 W/m3 of cathode volume). The microalgae growth in the biocathode chamber followed in terms of optical density. The optical density increased from 0.546 at the beginning of the system operation to 1.71 after 24 days of operation period. The percentage removal of chemical oxygen demand (COD) of oil refinery wastewater was 97.33% and 79.22% in anode and cathode chamber, respectively. The microalgae in the biocathode were able to remove volatile compounds causing odor from the influent wastewater. TDS removal rate 159.722 ppm/h with initial TDS in desalination chamber of 35000 ppm.

Pesticide wastewater treatment using the combination of the microbial electrolysis desalination and chemical-production cell and Fenton process

The combination of the microbial electrolysis desalination and chemical-production cell (MEDCC) and Fenton process for the pesticide wastewater treatment was investigate in this study. Real wastewater with several toxic pesticides, 1633 mg/L COD, and 200 in chromaticity was used for the investigation. Results showed that desalination in the desalination chamber of MEDCC reached 78%. Organics with low molecular weights in the desalination chamber could be removed from the desalination chamber, resulting in 28% and 23% of the total COD in the acid-production and cathode chambers, respectively. The desalination in the desalination chamber and organic transfer contributed to removal of pesticides (e.g., triadimefon), which could not be removed with other methods, and of the organics with low molecular weights. The COD in the effluent of the MEDCC combined the Fenton process was much lower than that in the perixo-coagulaiton process (< 150 vs. 555 mg/L). The combined method consumed much less energy and acid for the pH adjustment than that the Fenton.

Removal Efficiency of Cu2+ and Zn2+ from Industrial Wastewater by Using Microbial Desalination Cell

The removal of Cu2+ and Zn2+ from industrial wastewater using the microbial desalination cell is studied. Both synthetic and industrial samples were haracterised in accordance with standard methods recommended for examination of water and wastewater. Synthetic samples used for the analysis were prepared with concentration 5; 25; 50; 75; 100 mg/L Cu2+ and Zn2+ in deionized water. The removal efficiency of each metal was analyzed after 30; 60; 90; 120; 150 min; psychrophilic, mesophilic, thermophilic and 2–3; 3–4; 4–5; 5–6 and 6–7 mg/L dissolved oxygen were monitored. The experiments were done on wastewater of electroplating industries in Isfahan, Iran, in optimum conditions. For data analysis, SPSS version 16 software was used. Optimum condition for removing Cu2+ and Zn2+ were found to be: 100 mg/L, 4.4 mg/L dissolved oxygen, 26°C and 120 min.

Assessment of the electricity generation, desalination and wastewater treatment capacity of a plant microbial desalination cell (PMDC)

Microbial desalination cell, a versatile technology for simultaneous wastewater treatment, desalination and power generation is hoped to solve the critical needs (water and energy) of the world. However, to achieve these, sustainable cathode is required. Thus, this research investigated the potential of Ceratophyllum demersum for the construction of an efficient and environmentally friendly biocathode. With the plant biocathode, a plant microbial desalination cell was developed which was able to cause a 10.22% desalination of a 35 g/l salt solution in a batch cycle. Though the maximum voltage produced was small (154 ± 0.33 mV), the cell was, however, able to achieve a 41.79% COD reduction from an initial of 645 ± 2.3 mg/l using 1.05% nitrate and 9.97% phosphorus in wastewater. Unsuitable growth conditions for the survival of C. demersum and high internal resistance of the PMDC were identified as the main causes of the low peak voltage and percentage desalination produced by this cell. Future research on plant microbial desalination cells should consider solving the stated challenges.

Influence of key operating parameters and bio-fouling on simultaneous desalination of seawater & reduction of organic wastes from petroleum industrial wastewater

ABSTRACT Bio-cathode microbial desalination cells are emerging technology that utilizes bioelectric potential from organic matter (petroleum refinery effluent) to enhance the desalination process along with the activity of microalgae (Scenedesmus abundans). In the present work, the system is assumed to be governed by interdependent key process variables such as salt concentration, anolyte concentration, and external resistance. Three different levels of salt concentration (5, 20 and 35 g L−1), anolyte concentration (250, 500 and 750 mg L−1), and external resistance (100, 560 and 1000 Ω) were analysed and optimized by the statistical and probabilistic tool such as Box Behnken design method and Genetic Algorithm to maximize the desalination performance. The optimized parameters such as salt concentration (35 g L−1), anolyte concentration (500 mg L−1), and external resistance (100 Ω) produced maximum desalination efficiency of 59.6%. The model also distinguished the influence of input parameters on the output responses such as significant responses (Salinity, Total dissolved solids, and Electrical conductivity) and non-significant responses (Chemical oxygen demand removal, power density, and algal growth). The model predicted the desalination efficiency with ±1.25% error. The high impact of bio-fouling was observed in Anion Exchange Membrane on comparison with Cation Exchange Membrane.

Accomplishing a N-E-W (nutrient-energy-water) synergy in a bioelectrochemical nitritation-anammox process

This study reports an investigation of the concept, application and performance of a novel bioelectrochemical nitritation-anammox microbial desalination cell (MDC) for resource-efficient wastewater treatment and desalination. Two configurations of anammox MDCs (anaerobic-anammox cathode MDC (AnAmoxMDC) and nitration-anammox cathode MDC (NiAmoxMDC)) were compared with an air cathode MDC (CMDC), operated in fed-batch mode. Results from this study showed that the maximum power density produced by NiAmoxMDC (1,007 mW/m3) was higher than that of AnAmoxMDC (444 mW/m3) and CMDC (952 mW/m3). More than 92% of ammonium-nitrogen (NH4+-N) removal was achieved in NiAmoxMDC, significantly higher than AnAmoxMDC (84%) and CMDC (77%). The NiAmoxMDC performed better than CMDC and AnAmoxMDC in terms of power density, COD removal and salt removal in desalination chamber. In addition, cyclic voltammetry analysis of anammox cathode showed a redox peak centered at −140 mV Vs Ag/AgCl confirming the catalytic activity of anammox bacteria towards the electron transfer process. Further, net energy balance of the NiAmoxMDC was the highest (NiAmoxMDC-0.022 kWh/m3 >CMDC-0.019 kWh/m3 >AnAmoxMDC-0.021 kWh/m3) among the three configurations. This study demonstrated, for the first time, a N-E-W synergy for resource-efficient wastewater treatment using nitritation-anammox process.

High-efficiency salt, sulfate and nitrogen removal and microbial community in biocathode microbial desalination cell for mustard tuber wastewater treatment

Considering there is no study involving simultaneous salt, sulfate and nitrogen removal from high-salinity mustard tuber wastewater (MTWW), biocathode microbial desalination cell (BMDC) was first constructed and used to treat MTWW. The results showed that 97.4% of salt, 99.7% of sulfate and 99.8% of nitrogen could be removed from MTWW. The relative abundances of electrgenic bacteria in anode and cathode were 15.95% and 15.10%, respectively, which greatly promoted the electricity generation and desalination. The bacteria involved in sulfate reduction in anode were the dominant population, with relative abundance of 13.94%. Microbial community analysis of cathode biofilm indicated that autotrophic nitrification-anaerobic denitrification, electrochemical reduction and anaerobic ammonium oxidation might coexist for high-efficiency nitrogen removal. Besides, the BMDC showed stable power output for 150 days. These findings provide a promising approach for efficient treatment of MTWW.

Improving wastewater treatment capacity by optimizing hydraulic retention time of dual-anode assembled microbial desalination cell system

In this study, two dual-anode assembled microbial desalination cells (DA-MDCs) composed of two anodes, one cathode and two membrane stacks were constructed, with a hollow fiber membrane (HFM) module coupling into the cathode to filtrate suspended solids and microbes. Enriched domestic wastewater treatment performance of the DA-MDC system under different hydraulic retention time (HRT) was investigated in detail. When HRT sequentially decreased from 10 h, 8 h, 6 h to 4 h, the conductivity in diluent effluent kept stable at first, but increased 519% at 4 h compared with 6 h. Nevertheless, the chemical oxygen demand, total nitrogen and total phosphorus in the effluent met the wastewater discharge standards in China at all HRTs. Additionally, transmembrane pressure of the HFM modules increased sharply when HRT changed from 6 h to 4 h. Therefore, HRT 6 h was selected as the optimal condition. Under such short HRT, the system realized wastewater treatment capacity of 10 L/d, surpassing all bio-cathode microbial desalination cell systems aiming to realize efficient treatment of domestic wastewater. Additionally, the salt removal rate of 0.215 g/h was more than two times compared with most similar systems. Finally, stratified microbial community structures in the cathodes of the system were found. This gave evidence on the efficient catholyte recirculation which might facilitate nitrogen removal from wastewater.

Trends and resource recovery in biological wastewater treatment system

Nutrient removal from wastewater is an essential task to protect natural water resource and its excess results in eutrophication. Faster resource depletion and environmental sustainability paves the way for wastewater treatment and resource recovery and bioelectrochemical systems (BES) were employed to attain the goal. The first generation, BES, microbial fuel cell (MFC), microbial electrochemical cell (MEC) and microbial desalination cells (MDC) were getting really good with wastewaters. However, to achieve improved performance, BESs with membrane systems (OsMFC and FO-OMBR) and combination systems (MFC-MEC; MEDCC) were introduced. This review pointed out that high strength wastewaters can enhance nutrient recovery and electricity generation. This review aims to explore the recovered sources in various states of matter as solid, liquid, gas and energy. Moreover, limiting factors for resource recovery such as membrane fouling, reverse solute flux, internal resistance, substrate type and COD removal efficiency are highlighted. Finally, future research prospects have been discussed.

Simultaneous power generation and pollutant removals using microbial desalination cell at variable operation modes

The performance of microbial desalination cells was investigated concurrently under different substrate strengths and variable external resistances. When the external resistance was fixed at 1,000 Ω, the maximum voltage was 710, 694 and 650 mV at substrate COD concentrations of 500, 1500 and 3000 mg/l respectively. The average COD removal efficiencies were 90.0 ± 5.2, 92.3 ± 4.3 and 53.4 ± 7.2% at substrate concentrations of 500, 1500 and 3000 mg/l respectively. The cell operated at high substrate strength achieved the lowest voltage generation and highest internal resistance. Columbic Efficiencies (CEs) increased with decreased COD loading rates. The cell operated at medium substrate strength achieved the best desalination efficiency due to substrate availability and the lowermost internal resistance. Further investigation was made at different external resistances of 10 to 10,000 Ω which were found to have a significant effect on COD removal and CEs. The high desalination efficiencies were accompanied by higher current densities. Scanning Electron Microscopy (SEM) analyses were conducted for the anode electrode to investigate the biofilm morphology. This study demonstrated interesting results regarding the operation modes that could contribute to the microbial desalination cells scale up.

Enhancing the water desalination and electricity generation of a microbial desalination cell with a three-dimensional macroporous carbon nanotube-chitosan sponge anode

Microbial desalination cells (MDCs) are promising bioelectrochemical systems that are being investigated for simultaneous seawater desalination, electricity generation, and wastewater treatment. Anode materials play an important role in determining the performance of MDCs. In this study, a three-dimensional (3D) macroporous sponge was coated with compatible and conductive carbon nanotube-chitosan (CNT-CS) as a composite electrode for MDCs. Experimental results showed that the flexible CNT-CS sponge exhibited a high capacitance (159.4F/g at 20mVs−1), good cycling stability (96% specific capacitance retention after 1000 cyclic voltammetry cycles) and low resistance. Moreover, the MDC with a CNT-CS sponge anode generated a high power density of 1776.6mW/m2 (per electrode area) and desalination rate of 16.5mgh−1, which are significantly higher than those of commercial carbon felt electrodes under the same conditions. The improved MDC performance can be attributed to the continuous 3D macroporous structure of the sponge anode promoting the bacterial loading capacity on the electrode surface. Moreover, the presence of CNTs also further enhances extracellular electron transfer. Our results demonstrate that an MDC operating with a 3D CNT-CS sponge anode offers an effective means for manufacturing high-performance MDCs with wide applicability to bioelectrochemical systems.

Evaluating the performance of Microbial Desalination Cells subjected to different operating temperatures

Operational conditions have a tremendous effect on the performance of Microbial Desalination Cells (MDCs). In this study, MDCs were tested at three different temperatures zones; 45, 27 and 12 °C. Average COD removal efficiencies were 78 ± 5, 80 ± 6 and 46 ± 10% at 45, 27, and 12 °C, respectively and the average desalination efficiencies were 22.7 ± 5.8, 17.5 ± 5 and 9.4 ± 4.3% respectively. High columbic efficiencies were obtained of 9.7% at 45 °C and 11.28% at 27 °C, compared with a significantly lower value of 1.04% at 12 °C. Higher columbic efficiencies were correlated to lower COD removal rates. The increase in temperature resulted in a reduction in the internal resistance which improves the desalination. The maximum current densities of 402, 407 and 31 mA/m2 were recorded at 45, 27 and 12 °C respectively. Higher current densities were attained at both 45 and 27 °C while the cell operated at 27 °C only achieved sustained stable densities. The results of microbial community qualification indicated prevalence of three common strains at the three cells and a selective strain at each temperature zone. Scanning electron microscopy results revealed colour changes and distortion of the membranes. This study demonstrated that the MDCs are adaptable to function at different operation temperatures.

Desalination and power generation of caspian sea by applying new designed microbial desalination cells in batch operation mode

The Caspian Sea is one of the largest water sources located in the north of Iran; so this research was carried out to investigate the new design of microbial desalination cell (MDC) (double layer) efficiency in water desalination and power generation of the enormous saline water source in the north of Iran. Actual (i.e., Caspian Sea) and artificial seawater with different initial salt concentrations (5, 25, and 35 g/L NaCl) and, different hydraulic retention times (24, 48, and 72 h) in batch and open circuit voltage (OCV) mode were examined. In addition, the oxidation and reduction processes during desalination of each stage were monitored at 10 min intervals for 60 min. According to the obtained experimental data, both the desalination efficiency and the power generation decreased from 65 ± 1% to 41 ± 1% and 80 ± 4.5 mW/cm2 to 51.20 ± 2.5 mW/cm2 by increasing the retention time from 24 to 72 h for Caspian Sea water and 5 g/L NaCl, respectively. Maximum and minimum desalination efficiencies were 48 ± 1% and 65 ± 1% for Caspian Sea water and 5 g/L NaCl, respectively. Moreover, the maximum power densities were 72.83 ± 3.36 mW/cm2 and 80.00 ± 4.00 mW/cm2 for 35 g/L NaCl and seawater, respectively. As far as the authors know, this is the first study on the application of the new designed stacked MDC for power generation and desalination of water from the Caspian Sea. © 2019 American Institute of Chemical Engineers Environ Prog, 38:e13146, 2019