Recent Submissions

  • An Integrated Photocatalytic and Photothermal Process for Solar-Driven Efficient Purification of Complex Contaminated Water

    Shi, Le; Shi, Yusuf; Zhang, Chenlin; Zhuo, Sifei; Wang, Wenbin; Li, Renyuan; Wang, Peng (Energy Technology, Wiley, 2020-07-31) [Article]
    With the water and energy crises becoming critical issues for an increasingly industrialized society, solar-driven water purification technologies are highly desired for both potable water production and wastewater treatment. Herein, the performance of an integrated photocatalytic and photothermal composite, TiO2/Au-carbon nanotube (TiO2/Au-CNT)-coated SiC ceramic plate, in complex contaminated water treatment driven by solar energy is investigated. The short-wavelength part of the solar spectrum is used for simultaneous photo-oxidation of rhodamine B (RhB) (oxidation efficiency of ≈98.5%) and photo-reduction of Cr(VI) (reduction efficiency of ≈90.6%) in an integrated solar still device. A Z-scheme charge transfer mechanism with CNTs as an electron mediator is proposed and discussed for TiO2/Au-CNT-coated SiC ceramic plate. Meanwhile, the design here allowed the long-wavelength part of the solar spectrum to be utilized for high-quality potable clean water production via solar distillation with a solar-to-water evaporation efficiency of ≈72%. Therefore, this integrated photocatalytic and photothermal system can be utilized for potable water production and wastewater treatment in the same device with high solar energy utilization efficiency.
  • Downscaling Multispectral Satellite Images Without Colocated High-Resolution Data: A Stochastic Approach Based on Training Images

    Oriani, Fabio; McCabe, Matthew; Mariethoz, Gregoire (IEEE Transactions on Geoscience and Remote Sensing, Institute of Electrical and Electronics Engineers (IEEE), 2020-07-30) [Article]
    Very high-resolution satellite imagery from the latest generation commercial platforms provides an unprecedented capacity for imaging the Earth with very high spatial detail. However, these data are generally expensive, particularly if large areas or temporal sequences are required. In recent years, lower quality imagery has been enabled through the launch of constellations of small satellites with short revisit time. In this article, we apply for the first time a statistical approach to downscale and bias-correct these multispectral satellite data using the information contained in a limited training set of very highresolution images. The technique, based on the direct sampling algorithm, aims at extending the coverage of high-resolution images by sampling data from a training data set, where similar lower resolution data patterns are found. Unlike the majority of the current downscaling techniques, the approach does not require colocated fine-resolution data, but it is based on the use of training images similar to the target zone. A novel specific setup is proposed, which is adaptive to different types of landscapes with no additional user effort. The results show that the proposed technique can generate more realistic images than the traditional approaches based on the parametric bias correction and bicubic interpolation. In particular, properties such as the intensity histogram, spatial correlation, and connectivity are accurately preserved. The proposed approach can be used to extend the footprint of the high-resolution images to generate new time frames or to downscale the remote sensing imagery based on a distant but structurally similar training image.
  • NEXARTM-coated hollow fibers for air dehumidification

    Upadhyaya, Lakshmeesha; Gebreyohannes, Abaynesh Yihdego; Akhtar, Faheem; Falca, Gheorghe; Musteata, Valentina-Elena; Mahalingam, Dinesh K.; Almansoury, Rneem; Ng, Kim Choon; Nunes, Suzana Pereira (Journal of Membrane Science, Elsevier BV, 2020-07-22) [Article]
    Air conditioning is one of the essential requirements for households as well as work stations. Dehumidification in air conditioning is the highest energy-consuming component, where membranes could play a crucial role. In this work, we propose the coating of NEXARTM, a commercial pentablock copolymer in tetrahydrofuran on polyetherimide hollow fiber support for separation of water vapor from humidified air. The block copolymer in tetrahydrofuran forms a lamellar/parallel cylindrical structure separated by equidistance during the morphological transformation process giving its unique characteristics with higher water vapor transfer efficiency. Both vacuum and sweep gas modes of membrane dehumidification strategies are investigated along with the detailed study of the morphological transformation process under a controlled environment, which is supported by comprehensive scanning electron microscopic and atomic force microscopic imaging. The membrane has shown water vapor permeance up to 9089 GPU with water vapor to nitrogen selectivity up to 3870. The membrane can reduce the relative humidity from 80% to 41% proving one of the competitive materials for membrane dehumidification.
  • Retrieval of High-Resolution Soil Moisture through Combination of Sentinel-1 and Sentinel-2 Data

    Ma, Chunfeng; Li, Xin; McCabe, Matthew (Remote Sensing, MDPI AG, 2020-07-20) [Article]
    Estimating soil moisture based on synthetic aperture radar (SAR) data remains challenging due to the influences of vegetation and surface roughness. Here we present an algorithm that simultaneously retrieves soil moisture, surface roughness and vegetation water content by jointly using high-resolution Sentinel-1 SAR and Sentinel-2 multispectral imagery, with an application directed towards the provision of information at the precision agricultural scale. Sentinel-2-derived vegetation water indices are investigated and used to quantify the backscatter resulting from the vegetation canopy. The proposed algorithm then inverts the water cloud model to simultaneously estimate soil moisture and surface roughness by minimizing a cost function constructed by model simulations and SAR observations. To examine the performance of VV- and VH-polarized backscatters on soil moisture retrievals, three retrieval schemes are explored: a single channel algorithm using VV (SCA-VV) and VH (SCA-VH) polarizations and a dual channel algorithm using both VV and VH polarizations (DCA-VVVH). An evaluation of the approach using a combination of a cosmic-ray soil moisture observing system (COSMOS) and Soil Climate Analysis Network measurements over Nebraska shows that the SCA-VV scheme yields good agreement at both the COSMOS footprint and single-site scales. The features of the algorithms that have the most impact on the retrieval accuracy include the vegetation water content estimation scheme, parameters of the water cloud model and the specification of initial ranges of soil moisture and roughness, all of which are comprehensively analyzed and discussed. Through careful consideration and selection of these factors, we demonstrate that the proposed SCA-VV approach can provide reasonable soil moisture retrievals, with RMSE ranging from 0.039 to 0.078 m3/m3 and R2 ranging from 0.472 to 0.665, highlighting the utility of SAR for application at the precision agricultural scale.
  • Colloidal stability of capped silver nanoparticles in natural organic matter-containing electrolyte solutions

    Gutierrez, Leonardo; Schmid, Andreas; Zaouri, Noor A.; Garces, Daniel; Croue, Jean Philippe (NanoImpact, Elsevier BV, 2020-07-19) [Article]
    Due to their increased production and commercial applications, capped silver nanoparticles (AgNPs) have inevitably found their way into aquatic ecosystems. The mobility (fate/transport), bioavailability, reactivity, and toxicity of capped AgNPs are highly influenced by their colloidal stability. This study investigated the aggregation kinetics and interfacial interactions of tannic acid (TA)-coated or silica-coated AgNPs in natural organic matter (NOM)-containing electrolyte solutions by time-resolved dynamic light scattering and atomic force microscopy. Three well-characterized NOM fractions of different characteristics were selected. In Na+-solutions, the polymeric TA induced more stability to AgNPs than the hard silica coating. Although all NOM fractions weakly interacted with TA even at high Na+ concentrations, these organics adsorbed on the silica-coated AgNPs; thus, inducing stability. Humic fractions provided higher colloidal stability due to stronger electrostatic/steric interactions. Ca2+ increased the aggregation kinetics of both capped nanoparticles in the absence and presence of NOM. However, the aggregation kinetics of TA-coated AgNPs in humic NOM-containing solution were higher than those of non-humic due to a higher content of deprotonated carboxyl groups and cation bridging mechanisms. The knowledge compiled in this study would assist in understanding and predicting the fate and transport of capped nanoparticles in natural aquatic systems of different compositions.
  • The Use of High-Throughput Phenotyping for Assessment of Heat Stress-Induced Changes in Arabidopsis

    Gao, Ge; Tester, Mark A.; Julkowska, Magdalena M. (Plant Phenomics, American Association for the Advancement of Science (AAAS), 2020-07-17) [Article]
    The worldwide rise in heatwave frequency poses a threat to plant survival and productivity. Determining the new marker phenotypes that show reproducible response to heat stress and contribute to heat stress tolerance is becoming a priority. In this study, we describe a protocol focusing on the daily changes in plant morphology and photosynthetic performance after exposure to heat stress using an automated noninvasive phenotyping system. Heat stress exposure resulted in an acute reduction of the quantum yield of photosystem II and increased leaf angle. In longer term, the exposure to heat also affected plant growth and morphology. By tracking the recovery period of the WT and mutants impaired in thermotolerance (hsp101), we observed that the difference in maximum quantum yield, quenching, rosette size, and morphology. By examining the correlation across the traits throughout time, we observed that early changes in photochemical quenching corresponded with the rosette size at later stages, which suggests the contribution of quenching to overall heat tolerance. We also determined that 6 h of heat stress provides the most informative insight in plant’s responses to heat, as it shows a clear separation between treated and nontreated plants as well as the WT and hsp101. Our work streamlines future discoveries by providing an experimental protocol, data analysis pipeline, and new phenotypes that could be used as targets in thermotolerance screenings.
  • Translational Molecular Ecology in practice: Linking DNA-based methods to actionable marine environmental management

    Aylagas, Eva; Aylagas, Eva; Pochon, Xavier; Zaiko, Anastasija; Keeley, Nigel; Bruce, Kat; Hong, Pei-Ying; Ruiz, Gregory M.; Stein, Eric D.; Theroux, Susanna; Geraldi, Nathan; Ortega, Alejandra; Gajdzik, Laura; Coker, Darren James; Katan, Yasser; Hikmawan, Tyas; Saleem, Ammar; Alamer, Sultan; Jones, Burton; Duarte, Carlos M.; Pearman, John; Carvalho, Susana (Science of The Total Environment, Elsevier BV, 2020-07-12) [Article]
    Molecular-based approaches can provide timely biodiversity assessments, showing an immense potential to facilitate decision-making in marine environmental management. However, the uptake of molecular data into environmental policy remains minimal. Here, we showcase a selection of local to global scale studies applying molecular-based methodologies for environmental management at various stages of implementation. Drawing upon lessons learned from these case-studies, we provide a roadmap to facilitate applications of DNA-based methods to marine policies and to overcome the existing challenges. The main impediment identified is the need for standardized protocols to guarantee data comparison across spatial and temporal scales. Adoption of Translational Molecular Ecology – the sustained collaboration between molecular ecologists and stakeholders, will enhance consensus with regards to the objectives, methods, and outcomes of environmental management projects. Establishing a sustained dialogue among stakeholders is the key to accelerating the adoption of molecular-based approaches for marine monitoring and assessment.
  • Light supports cell-integrity and growth rates of taxonomically diverse coastal photoheterotrophs.

    Arandia-Gorostidi, Nestor; González, José M; Huete-Stauffer, Tamara; Ansari, Mohd Ikram; Moran, Xose Anxelu G.; Alonso-Sáez, Laura (Environmental microbiology, Wiley, 2020-07-10) [Article]
    Despite the widespread distribution of proteorhodopsin (PR)-containing bacteria in the oceans, the use of light-derived energy to promote bacterial growth has only been shown in a few bacterial isolates, and there is a paucity of data describing the metabolic effects of light on environmental photoheterotrophic taxa. Here, we assessed the effects of light on the taxonomic composition, cell integrity and growth responses of microbial communities in monthly incubations between spring and autumn under different environmental conditions. The photoheterotrophs expressing PR in situ were dominated by Pelagibacterales and SAR116 in July and November, while members of Euryarchaeota, Gammaproteobacteria and Bacteroidetes dominated the PR expression in spring. Cell-membrane integrity decreased under dark conditions throughout most of the assessment, with maximal effects in summer, under low-nutrient conditions. A positive effect of light on growth was observed in one incubation (out of nine), coinciding with a declining phytoplankton bloom. Light-enhanced growth was found in Gammaproteobacteria (Alteromonadales) and Bacteroidetes (Polaribacter and Tenacibaculum). Unexpectedly, some Pelagibacterales also exhibited higher growth rates under light conditions. We propose that the energy harvested by PRs helps to maintain cell viability in dominant coastal photoheterotrophic oligotrophs while promoting growth of some widespread taxa benefiting from the decline of phytoplankton blooms. This article is protected by copyright. All rights reserved.
  • Simultaneous production of cooling and freshwater by an integrated indirect evaporative cooling and humidification-dehumidification desalination cycle

    Chen, Qian; Burhan, Muhammad; Shahzad, Muhammad Wakil; Ybyraiymkul, Doskhan; Akhtar, Faheem; Ng, Kim Choon (Energy Conversion and Management, Elsevier BV, 2020-07-10) [Article]
    Cooling and freshwater represent two fundamental demands in hot and arid regions. This paper reports the integration of an indirect evaporative cooler (IEC) and a humidification-dehumidification desalination cycle (HDH) for the simultaneous production of cooling and freshwater. To take full advantage of system integration, the purge air from IEC is supplied to HDH to promote water productivity. A pilot IEC unit is firstly designed and tested to achieve the temperatures and humidity of the outlet air steams. Results reveal that the IEC unit is able to cool down the supply air to below 25 °C under different outdoor conditions, and the purge air temperature is also 5–10 ℃ lower than the intake air temperature. Employing the IEC purge air as the working air, the HDH cycle is then investigated analytically. Under the operation ranges considered, the freshwater productivity and gain-output ratio (GOR) are 25–125 L/hr and 1.6–2.5, respectively, which are higher than other HDH configurations operating under the same conditions. Finally, the performance of the combined IEC-HDH system is evaluated. The overall coefficient of performance (COP) and Second-law efficiency are found to be 2.1–2.5 and 3–26%, respectively. Further improvement of efficiency can be achieved by integrating with adsorption or vapor compression refrigeration cycles.
  • Unlocking the Potential of Single Atoms Loaded Geobacter Hybrid Catalyst as Bifunctional Electrocatalyst for Water Splitting

    Pedireddy, Srikanth; Ravva, Mahesh Kumar; Nayak, Chandrani; Anjum, Dalaver H.; Jha, Shambhu Nath; Saikaly, Pascal (American Chemical Society (ACS), 2020-07-10) [Preprint]
    Here, we report a reproducible method for the synthesis of SA-Ms on the surface of the electroactive bacterium, Geobacter sulfurreducens (GS). Our approach is based on the extracellular electron transfer capability of GS to reduce extracellular metal ions by harvesting the metabolically formed electrons inside the cell. The formation of SA-Ms on the surface of GS was achieved by creating an MN3 moiety (where M=Ir, Pt, Co, Ru, Cu, and Pd, and N = nitrogen), identified by X-ray absorption fine structure analysis. Interestingly, our bio-derived SA-M@GS can be directly used as OER and HER electrocatalysts upon drying without further heat treatments such as pyrolysis or hydrothermal approaches.<br>
  • Evidence for intensification of meteorological droughts in Oman over the past four decades

    El Kenawy, Ahmed M.; Al Buloshi, Ali; Al Awadhi, Talal; Al Nasiri, Noura; Navarro-Serrano, Francisco; Alhatrushi, Salim; Robaa, S. M.; Domínguez-Castro, Fernando; McCabe, Matthew; Schuwerack, Petra Manuela; López-Moreno, Juan I.; Vicente-Serrano, Sergio M. (Atmospheric Research, Elsevier BV, 2020-07-08) [Article]
    Spatial and temporal variability of drought in Oman was assessed for the period 1979–2014 using the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI) at both seasonal (3-month) and annual (12-month) timescales. Changes in drought characteristics (e.g. frequency, duration, intensity, severity, and spatial extent) were detected for six distinct climatic regions delineated using a Principal Component Analysis (PCA). Results suggest a statistically significant increase in the frequency and severity of drought during the past four decades. Nonetheless, drought exhibited pronounced decadal variability, with more frequent and severe droughts occurring after 1997/1998. Also, results demonstrate that the areas influenced by extreme and very extreme droughts witnessed a statistically significant increase on the order of 0.13% and 0.18%/decade, respectively, compared to −0.06%/decade for the areas impacted by mild droughts. Spatially, there has been a prevalent drying trend in central and eastern regions of Oman, while a tendency towards wetter conditions was observed in northern Oman (especially in the Batinah plain). This study also investigates the time-varying dependency between climatic drivers of drought and large-scale circulation patterns using the cumulative annual mean (CAM) method. Results indicate an acceleration of drying after 1997/1998, mainly due to the warming sea surface temperature (SST) anomalies over the Atlantic Ocean in recent decades and also the shift of the Pacific Ocean circulation patterns (e.g. PDO and El Nino) from the positive to the negative mode at the end of the 1990s. These configurations are favorable for significant changes in the thermodynamic drivers of drought (i.e. air temperature and relative humidity), but have less influence on aerodynamic drivers (i.e. wind speed). The significant temperature rise in recent decades, combined with a significant decline of rainfall and relative humidity, can explain the prolonged drought episode lasting from 1998 to 2014. A comprehensive assessment of drought variability in a poorly-studied water-stressed region like Oman is of particular concern for stakeholders and policy-makers. This study provides meaningful conclusions and a basis for water resources management, agricultural and energy production, ecological protection, and contribute to more reliable drought mitigation strategies at the regional and national scales.
  • Physical and economical evaluation of laboratory-scale membrane bioreactor by long-term relative cost–benefit analysis

    Ayub, Mariam; Saeed, Nadeeha; Chung, Shinho; Nawaz, Muhammad Saqib; Ghaffour, NorEddine (Journal of Water Reuse and Desalination, IWA Publishing, 2020-07-08) [Article]
    Two laboratory-scale single-stage submerged membrane bioreactors (MBRs) were operated in parallel to examine the effect of different flux conditions and several fouling mitigation methods. After control operation (filtration only), three fouling control methods (relaxation, standard backwash and chemical backwash) at 27 LMH flux and four different flux conditions (54, 36, 27 and 18 LMH) with standard backwash were applied. Physical performance of MBRs was evaluated based on the operational duration to reach maximum transmembrane pressure and the volume of permeate produced during the operational duration. Then relative cost–benefit analysis was carried out. Results showed that the combination of chemical backwash and standard backwash was the most effective for fouling mitigation in terms of physical improvement of MBR performance. However, the combination proved less economical (400% + α relative cost) than standard backwash alone (343% relative cost), because of the additional cost for pumps and chemical. It also showed that lower flux (18 LMH) is desirable as it showed better physical performance (1,770% improvement as compared to the highest flux, 54 LMH) and proved more economical than higher flux configuration. Therefore, it is concluded that the operation with standard backwash at the lowest possible flux is the best combination to improve MBR performance as well as long-term cost–benefit.
  • Draft Genome Sequences of Three Bacillus Species Isolated from Biofouled Reverse-Osmosis Membranes

    Rehman, Zahid Ur; Iftikhar, Muhammad Ali; Leiknes, TorOve (Microbiology Resource Announcements, American Society for Microbiology, 2020-07-08) [Article]
    ABSTRACT Here, we present the draft genome sequences of three bacteria belonging to the genus Bacillus which were isolated from biofouled reverse-osmosis (RO) membranes harvested from a full-scale desalination plant. The sizes of the assembled genomes for RO1, RO2, and RO3 were 4.22 Mb, 4.15 Mb, and 4.23 Mb, respectively.
  • Comparative Genome-Centric Analysis of Freshwater and Marine ANAMMOX Cultures Suggests Functional Redundancy in Nitrogen Removal Processes

    Ali, Muhammad; Shaw, Dario Rangel; Albertsen, Mads; Saikaly, Pascal (Frontiers in Microbiology, Frontiers Media SA, 2020-07-07) [Article]
    There is a lack of understanding of the interaction between anammox bacteria and the flanking microbial communities in both freshwater (non-saline) and marine (saline) ecosystems. Here, we present a comparative genome-based exploration of two different anammox bioreactors, through the analysis of 23 metagenome-assembled genomes (MAGs), 12 from freshwater anammox reactor (FWR), and 11 from marine anammox reactor (MWR). To understand the contribution of individual members to community functions, we applied the index of replication (iRep) to determine bacteria that are actively replicating. Using genomic content and iRep information, we provided a potential ecological role for the dominant members of the community based on the reactor operating conditions. In the non-saline system, anammox (Candidatus Brocadia sinica) and auxotrophic neighboring bacteria belonging to the phyla Ignavibacteriae and Chloroflexi might interact to reduce nitrate to nitrite for direct use by anammox bacteria. Whereas, in the saline reactor, anammox bacterium (Ca. Scalindua erythraensis) and flanking community belonging to phyla Planctomycetes (different than anammox bacteria)—which persistently growing in the system—may catabolize detritus and extracellular material and recycle nitrate to nitrite for direct use by anammox bacteria. Despite different microbial communities, there was functional redundancy in both ecosystems. These results signify the potential application of marine anammox bacteria for treating saline N-rich wastewaters.
  • Biofouling control by phosphorus limitation strongly depends on the assimilable organic carbon concentration.

    Javier, Luisa; Farhat, Nadia M; Desmond, Peter; Linares, Rodrigo Valladares; Bucs,Szilard; Kruithof, Joop C; Vrouwenvelder, Johannes S. (Water research, Elsevier BV, 2020-07-05) [Article]
    Nutrient limitation is a biofouling control strategy in reverse osmosis (RO) membrane systems. In seawater, the assimilable organic carbon content available for bacterial growth ranges from about 50 to 400 μg C·L-1, while the phosphorus concentration ranges from 3 to 11 μg P·L-1. Several studies monitored biofouling development, limiting either carbon or phosphorus. The effect of carbon to phosphorus ratio and the restriction of both nutrients on membrane system performance have not yet been investigated. This study examines the impact of reduced phosphorus concentration (from 25 μg P·L-1 and 3 μg P·L-1, to a low concentration of ≤0.3 μg P·L-1), combined with two different carbon concentrations (250 C L-1 and 30 μg C·L-1), on biofilm development in an RO system. Feed channel pressure drop was measured to determine the effect of the developed biofilm on system performance. The morphology of the accumulated biomass for both carbon concentrations was characterized by optical coherence tomography (OCT) and the biomass amount and composition was quantified by measuring total organic carbon (TOC), adenosine triphosphate (ATP), total cell counts (TCC), and extracellular polymeric substances (EPS) concentration for the developed biofilms under phosphorus restricted (P-restricted) and dosed (P-dosed) conditions. For both carbon concentrations, P-restricted conditions (≤0.3 μg P·L-1) limited bacterial growth (lower values of ATP, TCC). A faster pressure drop increase was observed for P-restricted conditions compared to P-dosed conditions when 250 μg C·L-1 was dosed. This faster pressure drop increase can be explained by a higher area covered by biofilm in the flow channel and a higher amount of produced EPS. Conversely, a slower pressure drop increase was observed for P-restricted conditions compared to P-dosed conditions when 30 μg C·L-1 was dosed. Results of this study demonstrate that P-limitation delayed biofilm formation effectively when combined with low assimilable organic carbon concentration and thereby, lengthening the overall membrane system performance.
  • Dual-function ultrafiltration membrane constructed from pure activated carbon particles via facile nanostructure reconstruction for high-efficient water purification

    Yang, Kaijie; Pan, Tingting; Zhao, Qiang; Chen, Cheng; Zhu, Xiaoying; Wang, Peng; Chen, Baoliang (Carbon, Elsevier BV, 2020-07-05) [Article]
    Activated carbon (AC) particles, as some of the most widely used sorbents, have an indispensable position in environmental remediation. Although AC surface adsorption was extensively investigated, its internal nanostructure has not been well elucidated. Exploitation of the internal nanostructure for pollution abatement is worthwhile pursuing to expand AC application field. Herein, the internal nanostructures of AC particle are revealed by step-by-step exfoliation and characterization, indicating that an AC particle is composed of multilevel nanostructures including carbon nanospheres and graphene-like layers to a certain extent. AC particles can be transformed into an ultrafiltration membrane through a newly developped structure exfoliation and reconstruction processes under surface regulation without additional cross-linkers. The pure AC membrane (ACM) preserves the adsorption capacity of AC particles, and further endows AC with the function of membrane separation. The ACM shows excellent stability, strong adsorption capacity (252.4 mg/g for methylene blue), narrow sieving pores distribution (5–10 nm), low-fouling property for cycling use. The considerable water flux is 12–27 times higher than commercial ultrafiltration membrane. Dual-function performances of adsorption and separation make the ACM high potential in water purification. This approach for particle-to-membrane transformation provides a new perspective for AC particle future utilization.
  • Effect of organic micropollutants on biofouling in a forward osmosis process integrating seawater desalination and wastewater reclamation

    Kim,Youngjin; Kim, Lan Hee; Vrouwenvelder, Johannes S.; Ghaffour, NorEddine (Journal of Hazardous Materials, Elsevier BV, 2020-07-04) [Article]
    This study systematically investigated the effect of organic micropollutants (OMPs) on biofouling in forward osmosis (FO) integrating wastewater treatment and seawater dilution. Synthetic seawater (0.6 M sodium chloride) was used as a draw solution and synthetic municipal wastewater as a feed solution. To evaluate the impact of OMPs in a replicate parallel study, wastewater was supplemented with a mixture of 7 OMPs (OMPs-feed) and without OMPs (control) during 8 batch filtration cycles with feed and draw solution replacement after each filtration. The FO performance (water flux), development and microbial composition properties of biofilm layers on the wastewater side of the FO membrane were studied. Compared to the control without OMPs, the FO fed with OMPs containing wastewater showed (i) initially the same water flux and flux decline during the first filtration cycle, (ii) with increasing filtration cycle a lower flux decline and (iii) lower concentrations for the total cells, ATP, EPS carbohydrates and proteins in biofilm layers, and (iv) a lower diversity of the biofilm microbial community composition (indicating selective pressure) and (v) increasing rejection of 6 of the 7 OMPs. In essence, biofouling on the FO membrane showed (i) a lower flux decline in the presence of OMPs in the feed water and (ii) a higher OMPs rejection, both illustrating better membrane performance. This study has a significant implication for optimizing osmotic dilution in terms of FO operation and OMPs rejection.
  • Bioconversion of swine manure into high-value products of medium chain fatty acids.

    Zhang, Wanqin; Yin, Fubin; Dong, Hongmin; Cao, Qitao; Wang, Shunli; Xu, Jiajie; Zhu, Zhiping (Waste management (New York, N.Y.), Elsevier BV, 2020-07-03) [Article]
    This research proposes and demonstrates, for the first time, the utilization of swine manure as a complex feedstock to produce high-value medium chain fatty acids (MCFA). The two-stage anaerobic digestion (AD) carboxylates platform was adopted for the conversion of swine manure to short chain fatty acids (SCFAs) and then SCFAs to MCFA (n-caproate, n-heptanoate, and n-caprylate) with ethanol supplementation. We defined the appropriate initial pH of 10.0 for SCFAs production with a carbon conversion rate of 71.2%, and acetate, propionate were the main products, which accounted for around 72.9% of the total SCFAs in the primary stage (I). Through the addition of ethanol, 61.3% of the converted carbon in the complex SCFAs solution was converted into MCFA (C6-C8) in the chain elongation stage (II), while only 6.7% was attributed to methane formation. The concentrations of n-caproate, n-heptanoate, and n-caprylate reached 8.6 g COD/L (3.9 g/L), 6.4 g COD/L (2.7 g/L), and 2.6 g COD/L (1.07 g/L), respectively. This study achieved a relatively higher concentration of n-heptanoate compared with past studies of MCFA from other feedstock. These findings demonstrated a new route for resource recovery and the operating parameters for producing MCFA from swine manure.
  • A Robust, Safe and Scalable Magnetic Nanoparticle Workflow for RNA Extraction of Pathogens from Clinical and Environmental Samples

    Ramos Mandujano, Gerardo; Salunke, Rahul; Mfarrej, Sara; Rachmadi, Andri Taruna; Hala, Sharif; Xu, Jinna; Alofi, Fadwa S; Khogeer, Asim; Hashem, Anwar M; Almontashiri, Naif AM; Alsomali, Afrah; Hamdan, Samir; Hong, Pei-Ying; Pain, Arnab; Li, Mo (Cold Spring Harbor Laboratory, 2020-06-29) [Preprint]
    Diagnosis and surveillance of emerging pathogens such as SARS-CoV-2 depend on nucleic acid isolation from clinical and environmental samples. Under normal circumstances, samples would be processed using commercial proprietary reagents in Biosafety 2 (BSL-2) or higher facilities. A pandemic at the scale of COVID-19 has caused a global shortage of proprietary reagents and BSL-2 laboratories to safely perform testing. Therefore, alternative solutions are urgently needed to address these challenges. We developed an open-source method called Magnetic- nanoparticle-Aided Viral RNA Isolation of Contagious Samples (MAVRICS) that is built upon reagents that are either readily available or can be synthesized in any molecular biology laboratory with basic equipment. Unlike conventional methods, MAVRICS works directly in samples inactivated in acid guanidinium thiocyanate-phenol-chloroform (e.g., TRIzol), thus allowing infectious samples to be handled safely without biocontainment facilities. Using 36 COVID-19 patient samples, 2 wastewater samples and 1 human pathogens control sample, we showed that MAVRICS rivals commercial kits in validated diagnostic tests of SARS-CoV-2, influenza viruses, and respiratory syncytial virus. MAVRICS is scalable and thus could become an enabling technology for widespread community testing and wastewater monitoring in the current and future pandemics.
  • A greener seawater desalination method by direct-contact spray evaporation and condensation (DCSEC): Experiments

    Alrowais, Raid Naif; Qian, Chen; Burhan, Muhammad; Ybyraiymkul, Doskhan; Shahzad, Muhammad Wakil; NG, Kim Choon (Applied Thermal Engineering, Elsevier BV, 2020-06-29) [Article]
    Owing to the high specific energy consumption of conventional seawater desalination methods available hitherto, there is much motivation for designing greener desalination processes. As a greener desalination process, it should consume lower top-brine temperatures for the seawater feed as well as minimum chemical use for brine treatment. In this paper, a direct-contact spray-assisted evaporation and condensation (DCSEC) is presented that addresses the above-mentioned requirements of greener desalination. We have tested both the single-stage and multi-stage configurations of DCSEC process with seawater (3.5% by weight salinity) from Red Sea. The performance of the system was investigated for a feed flow rate of 6 L/minute when the evaporator chamber temperature was varied from 38 °C to 60 °C. From the experiments, maximum distillate production of 31 L/hr m3 was recorded at 60 °C feed temperature for a single-stage configuration. To further enhance the distillate production of DCSEC, an innovative micro/nano-bubbles (M/NBs) generator device is incorporated in the feed supply system which resulted in 34% increase in potable water production at the corresponding inlet feed temperatures.

View more