Water Desalination and Reuse Research Center (WDRC)

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  • Article

    A clear view of biofouling in spacer filled membrane filtration channels: Integrating OCT and CT for improved visualization and localization

    (Elsevier BV, 2024-02) Huisman, Kees; Fortunato, Luca; Vrouwenvelder, Johannes S.; Blankert, Bastiaan; Environmental Science and Engineering Program, Biological and Environmental Science & Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia; Environmental Science and Engineering Program; Biological and Environmental Science and Engineering (BESE) Division; Water Desalination and Reuse Research Center (WDRC)

    Spiral wound membrane elements for reverse osmosis (RO) seawater desalination are increasingly important to produce clean water to cope with the rising global freshwater scarcity. Spiral wound elements are prone to biofouling development which can be monitored in-situ using optical coherence tomography (OCT). Although OCT has emerged as a dominant technology for nondestructive monitoring of membrane fouling, the application of OCT to study fouling on feed spacers has been limited because image processing of spacers is complex. In this study, an automated image processing algorithm was developed for visualization and quantification of fouling in spacer filled channels. The spacer shadow was used to estimate the location of the spacer in the OCT image. Subsequently, a computed tomography (CT) scan of the same spacer type was overlaid, providing a clear indicator of the spacer position. The spacer position was used to i) correct the distortion below the spacer, ii) visualize fouling in 3D with reference to the membrane and spacer, and iii) reproducibly and precisely locate images to make time series and compare parallel experiments. The results showed that the addition of a spacer geometry as a solid object in a 3D representation of an OCT scan greatly improves visualization, because fouling and the spacer can be distinguished and the position of fouling relative to the spacer and membrane can be clearly seen. Moreover, the ability to select a dataset relative to the orientation of the spacer will enable objective and automated quantitative analysis in future work.

  • Article

    Biofilm rigidity, mechanics and composition in seawater desalination pretreatment employing Ultrafiltration and Microfiltration membranes.

    (Elsevier BV, 2024-02) Ranieri, Luigi; Esposito, Rebecca; Nunes, Suzana Pereira; Vrouwenvelder, Johannes S.; Fortunato, Luca; Environmental Science & Engineering Program (EnSE), Biological and Environmental Science & Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia; Advanced Membranes and Porous Materials (AMPM) Center, King Abdullah University of Science and Technology (KAUST), Saudi Arabia; Chemistry Program and Chemical Engineering Program, Physical Science and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), 23955-6900 Thuwal, Saudi Arabia; Environmental Science and Engineering Program; Biological and Environmental Science and Engineering (BESE) Division; Advanced Membranes and Porous Materials Research Center; Office of the Provost; Water Desalination and Reuse Research Center (WDRC); Physical Science and Engineering (PSE) Division; Chemical Engineering Program; Chemical Science Program; MANN+HUMMEL Water & Fluid Solutions S.p.A., Italy

    The choice of appropriate biofilm control strategies in membrane systems for seawater desalination pretreatment relies on understanding the properties of the biofilm formed on the membrane. This study reveals how the biofilm composition, including both organic and inorganic, influenced the biofilm behavior under mechanical loading. The investigation was conducted on two Gravity-Driven Membrane reactors employing Microfiltration (MF) and Ultrafiltration (UF) membrane for the pretreatment of raw seawater. After a stabilization period of 20 days (Phase I), a biofilm behavior test was introduced (Phase II) to evaluate (i) biofilm deformation during the absence of permeation (i.e., relaxation) and (ii) biofilm resistance to detachment forces (i.e., air scouring). The in-situ monitoring investigation using Optical Coherence Tomography (OCT) revealed that the biofilms developed on MF and UF membrane presented a rigid structure in absence of filtration forces, limiting the application of relaxation and biofilm expansion necessary for cleaning. Moreover, under shear stress conditions, a higher reduction in biofilm thickness was observed for MF (−60%, from 84 to 34 µm) compared to UF (−30%, from 64 to 45 µm), leading to an increase of permeate flux (+60%, from 9.1 to 14.9 L/m2/h and +20 % from 7.8 to 9.5 L/m2/h, respectively). The rheometric analysis indicated that the biofilm developed on MF membrane had weaker mechanical strength, displaying lower storage modulus (−50 %) and lower loss modulus (−55 %) compared to UF. These differences in mechanical properties were linked to the lower concentration of polyvalent ions and the distribution of organic foulants (i.e., BB, LMW-N) found in the biofilm on the MF membrane. Moreover, in the presence of air scouring led to a slight difference in microbial community between UF and MF.

    Our findings provide valuable insight for future investigations aimed at engineer biofilm composition to optimize biofilm control strategies in membrane systems for seawater desalination pretreatme

  • Article

    Metal–organic framework-based atmospheric water harvesting for enhanced photovoltaic efficiency and sustainability

    (Royal Society of Chemistry (RSC), 2024) Alezi, Dalal; Li, Renyuan; Alsadun, Norah Sadun; Malik, Arijit; Shekhah, Osama; Wang, Peng; Eddaoudi, Mohamed; Water Desalination and Reuse Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia; Functional Materials Design, Discovery, and Development Research Group (FMD3), Advanced Membranes and Porous Materials Center (AMPM), Division of Physical Sciences and Engineering (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia; Environmental Science and Engineering Program; Biological and Environmental Science and Engineering (BESE) Division; Chemical Science Program; Physical Science and Engineering (PSE) Division; Advanced Membranes and Porous Materials Research Center; Water Desalination and Reuse Research Center (WDRC); Department of Chemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia; Department of Chemistry, College of Science, King Faisal University (KFU), Al-Ahsa 31982-400, Saudi Arabia

    The global demand for photovoltaic (PV) cooling is projected to increase over the coming years, driven by the growing adoption of solar energy and the need to improve the efficiency and performance of PV systems. Atmospheric water harvesting-based evaporative cooling (AWH-EC) has the potential to be a key technology for providing sustainable and low-cost cooling. Here, the super-adsorbent Cr-soc-MOF-1 is introduced and integrated in a sorption based atmospheric water harvester photovoltaic cooling system. Our results show that the AWH-based cooling component can provide 68.9–136.1 W m−2 cooling power, and the temperature of the PV panel can be reduced by ∼10.6–12.6 °C under 0.8–1.1 kW m−2 sunlight irradiation. Markedly, the integrated system demonstrates an increase in electricity generation of up to 7.5%. The feasibility of scaling up this cooling strategy is further predicted by simulation, indicating that it is a promising approach to fulfill the cooling demand in the PV industry with broad adaptability.

  • Article

    Low-temperature desalination driven by waste heat of nuclear power plants: A thermo-economic analysis

    (Elsevier BV, 2024-01-21) Zhong, Ziqiang; Burhan, Muhammad; Ng, Kim Choon; Cui, Xin; Chen, Qian; Water Desalination and Reuse Research Center (WDRC); Biological and Environmental Science and Engineering (BESE) Division; Environmental Science and Engineering Program; Institute for Ocean Engineering, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; Institute of Building Environment and Sustainable Technology, Xi'’an Jiaotong University, Xi'an, China

    Nuclear desalination is one of the ideal options to achieve net-zero emissions. However, most nuclear desalination plants extract steam from the power cycle to drive desalination, leading to a reduction of electricity output. To avoid the parasitic effects of desalination on the power cycle, this study considers recovering waste heat from the power plants' condensers to drive low-temperature desalination systems, including spray-assisted low-temperature desalination system (SLTD), multi-effect distillation system (MED) and spray-assisted multi-effect distillation system (SMED). Thermodynamic and economic models of the three desalination systems are firstly established and validated with experimental data. Then, the impacts of key design, operation and economic parameters are evaluated using the validated models. Results reveal that the productivity and thermodynamic efficiency are promoted by increasing the cooling water flowrate of desalination condenser, enlarging the heat exchanger area and lifting the heat source temperature, while the number of effects has an optimal value of 3. Under the optimal configuration, the gained-output ratio and Second Law efficiency of a 20 m3/day SLTD plant are 0.71 and 1.25 % respectively. In terms of economic performance, the levelized-cost of desalinated water (LCOW) for three plants can be reduced substantially under a larger plant capacity and longer lifespan. When the plant capacity exceeds 20,000 m3/day, the LCOW of SLTD can be reduced to 0.757 $/m3, which is lower than all other desalination systems coupled with power plants or renewable energy sources.

  • Article

    Faradaic Rectification in Electrochemical Deionization and Its Influence on Cyclic Stability

    (American Chemical Society (ACS), 2024-01-26) Li, Yuquan; Li, Renyuan; Wu, Mengchun; Shi, Le; Wang, Xiaozhi; Wang, Peng; Wang, Wenbin; Water Desalination and Reuse Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia; Water Desalination and Reuse Research Center (WDRC); Biological and Environmental Science and Engineering (BESE) Division; Environmental Science and Engineering Program; College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225127, Jiangsu, P. R. China; Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, P. R. China; School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, P. R. China

    Capacitive deionization (CDI) is a typical configuration of electrochemical deionization, which suffers from severe desalination capacity degradation derived from uncontrolled parasitic reactions. In this work, Faradaic rectification, the phenomenon by which electrode potentials and side reactions are dynamically regulated due to the asymmetrical anode/cathode Faradaic reactions, was studied under various CDI operation conditions. It was found that the Faradaic rectification in CDI would lead to capacity degradation indirectly by accelerating carbon anode oxidation and would be influenced by the cell voltage, flow rate, and asymmetric electrode construction. We also found an unconventional degradation mechanism in Faradaic cathode hybrid-CDI (HCDI) caused by the dramatic electrode-potential redistribution, which is derived from Faradaic rectification rather than the electrode structure decay. By adding a cation-exchange membrane to block the dissolved oxygen from cathode, the Faradaic rectification was suppressed successfully, and thus, the cyclic performance of CDI and HCDI was significantly increased by 59 and 46%, respectively (in 100 h cycling). This study provides an insight into understanding the Faradaic rectification in electrochemical deionization and its influence on CDI/HCDI cyclic stability, which should be of value to future explore cost-competitive membrane-less electrochemical deionization construction.