Recent Submissions

  • Integrated solar-driven PV cooling and seawater desalination with zero liquid discharge

    Wang, Wenbin; Aleid, Sara; Shi, Yifeng; Zhang, Chenlin; Li, Renyuan; Wu, Mengchun; Zhuo, Sifei; Wang, Peng (Joule, Elsevier BV, 2021-06-16) [Article]
    Utilizing the ‘‘waste heat’’ of solar cells for desalination enables the simultaneous production of freshwater and electricity and represents low barrier-of-entry electricity and freshwater supplies to off-grid communities for point of consumption. Herein, guided by theoretical modeling, this project demonstrated that a higher freshwater production rate and a lower solar cell temperature could be achieved simultaneously. With a five-stage photovoltaics-membrane distillation-evaporative crystallizer (PME), we experimentally demonstrated a high and stable freshwater production rate of 2.45 kg m2 h1 and a reduced solar cell temperature of 47 C under 1 sun irradiation, as compared to 62 C of the same solar cell working alone. The reduced solar cell temperature led to an 8% increase in its electricity production. Moreover, the concentrated brine produced in the process was fully evaporated by the underlying evaporative crystallizer, achieving zero liquid discharge. We expect that our work will have important implications for the understanding and advancement of solar distillation.
  • Plateau–Rayleigh Instability Induced Self-Assembly of Nano-Cubes in Stretched DNA Molecules

    Zhang, Peng; Yang, Zi Qiang; Thoroddsen, Sigurdur T; Di Fabrizio, Enzo (Submitted to MNE2021 - 47th international conference on Micro and Nano Engineering, 2021-06-13) [Preprint]
  • CubeSats deliver new insights into agricultural water use at daily and 3 m resolutions

    Aragon Solorio, Bruno Jose Luis; Ziliani, Matteo G.; Houborg, Rasmus; Franz, Trenton E.; McCabe, Matthew (Scientific Reports, Springer Science and Business Media LLC, 2021-06-09) [Article]
    Earth observation has traditionally required a compromise in data collection. That is, one could sense the Earth with high spatial resolution occasionally; or with lower spatial fidelity regularly. For many applications, both frequency and detail are required. Precision agriculture is one such example, with sub-10 m spatial, and daily or sub-daily retrieval representing a key goal. Towards this objective, we produced the first cloud-free 3 m daily evaporation product ever retrieved from space, leveraging recently launched nano-satellite constellations to showcase this emerging potential. Focusing on three agricultural fields located in Nebraska, USA, high-resolution crop water use estimates are delivered via CubeSat-based evaporation modeling. Results indicate good model agreement (r2 of 0.86–0.89; mean absolute error between 0.06 and 0.08 mm/h) when evaluated against corrected flux tower data. CubeSat technologies are revolutionizing Earth observation, delivering novel insights and new agricultural informatics that will enhance food and water security efforts, and enable rapid and informed in-field decision making.
  • Natural deep eutectic solvents as biofilm structural breakers

    Nava Ocampo, Maria F.; Al Fuhaid, Lamya; Verpoorte, Robert; Choi, Young Hae; van Loosdrecht, Mark C.M.; Vrouwenvelder, Johannes S.; Witkamp, Geert Jan; Farinha, Andreia S.F.; Bucs,Szilard (Water Research, Elsevier BV, 2021-06) [Article]
    Natural Deep Eutectic Solvents (NADES) are composed of supramolecular interactions of two or more natural compounds, such as organic acids, sugars, and amino acids, and they are being used as a new media alternative to conventional solvents. In this study, a new application of NADES is presented as a possible technology for biofilm structural breaker in complex systems since the current solvents used for biofilm cleaning and extraction of biofilm components use hazardous solutions. The NADES (betaine:urea:water and Lactic acid:glucose:water) were analyzed before and after the biofilm treatment by attenuated total reflection Fourier-transform infrared spectroscopy and fluorescence excitation-emission matrix spectroscopy. Our results indicate that the green solvents could solubilize up to ≈70 percent of the main components of the biofilms extracellular matrix. The solubilization of the biomolecules weakened the biofilm structure, which could enhance the biofilm solubilization and removal. The NADES have the potential to be an environment-friendly, green solvent to extract valuable compounds and break the main structure from the biofilm, leading to a greener method for extracellular polymeric substance (EPS) extraction and biofilm treatment in various water treatment systems.
  • Competition of two highly specialized and efficient acetoclastic electroactive bacteria for acetate in biofilm anode of microbial electrolysis cell

    Sapireddy, Veerraghavulu; Katuri, Krishna; Ali, Muhammad; Saikaly, Pascal (npj Biofilms and Microbiomes, Springer Science and Business Media LLC, 2021-05-31) [Article]
    Maintaining functional stability of microbial electrolysis cell (MEC) treating wastewater depends on maintaining functional redundancy of efficient electroactive bacteria (EAB) on the anode biofilm. Therefore, investigating whether efficient EAB competing for the same resources (electron donor and acceptor) co-exist at the anode biofilm is key for the successful application of MEC for wastewater treatment. Here, we compare the electrochemical and kinetic properties of two efficient acetoclastic EAB, Geobacter sulfurreducens (GS) and Desulfuromonas acetexigens (DA), grown as monoculture in MECs fed with acetate. Additionally, we monitor the evolution of DA and GS in co-culture MECs fed with acetate or domestic wastewater using fluorescent in situ hybridization. The apparent Monod kinetic parameters reveal that DA possesses higher jmax (10.7 ± 0.4 A/m2) and lower KS, app (2 ± 0.15 mM) compared to GS biofilms (jmax: 9.6 ± 0.2 A/m2 and KS, app: 2.9 ± 0.2 mM). Further, more donor electrons are diverted to the anode for respiration in DA compared to GS. In acetate-fed co-culture MECs, DA (98% abundance) outcompete GS for anode-dependent growth. In contrast, both EAB co-exist (DA: 55 ± 2%; GS: 24 ± 1.1%) in wastewater-fed co-culture MECs despite the advantage of DA over GS based on kinetic parameters alone. The co-existence of efficient acetoclastic EAB with high current density in MECs fed with wastewater is significant in the context of functional redundancy to maintain stable performance. Our findings also provide insight to future studies on bioaugmentation of wastewater-fed MECs with efficient EAB to enhance performance.
  • Assessment of the Impact of Temperature on Biofilm Composition with a Laboratory Heat Exchanger Module

    Pinel, Ingrid S M; Biškauskaitė, Renata; Pal’ová, Ema; Vrouwenvelder, Johannes S.; van Loosdrecht, Mark C.M. (Microorganisms, MDPI AG, 2021-05-31) [Article]
    Temperature change over the length of heat exchangers might be an important factor affecting biofouling. This research aimed at assessing the impact of temperature on biofilm accumulation and composition with respect to bacterial community and extracellular polymeric substances. Two identical laboratory-scale plate heat exchanger modules were developed and tested. Tap water supplemented with nutrients was fed to the two modules to enhance biofilm formation. One “reference” module was kept at 20.0 ± 1.4 °C and one “heated” module was operated with a counter-flow hot water stream resulting in a bulk water gradient from 20 to 27 °C. Biofilms were grown during 40 days, sampled, and characterized using 16S rRNA gene amplicon sequencing, EPS extraction, FTIR, protein and polysaccharide quantifications. The experiments were performed in consecutive triplicate. Monitoring of heat transfer resistance in the heated module displayed a replicable biofilm growth profile. The module was shown suitable to study the impact of temperature on biofouling formation. Biofilm analyses revealed: (i) comparable amounts of biofilms and EPS yield in the reference and heated modules, (ii) a significantly different protein to polysaccharide ratio in the EPS of the reference (5.4 ± 1.0%) and heated modules (7.8 ± 2.1%), caused by a relatively lower extracellular sugar production at elevated temperatures, and (iii) a strong shift in bacterial community composition with increasing temperature. The outcomes of the study, therefore, suggest that heat induces a change in biofilm bacterial community members and EPS composition, which should be taken into consideration when investigating heat exchanger biofouling and cleaning strategies. Research potential and optimization of the heat exchanger modules are discussed.
  • Detection of banana plants using multi-temporal multispectral uav imagery

    Aeberli, Aaron; Johansen, Kasper; Robson, Andrew; Lamb, David W.; Phinn, Stuart (Remote Sensing, MDPI AG, 2021-05-28) [Article]
    Unoccupied aerial vehicles (UAVs) have become increasingly commonplace in aiding planning and management decisions in agricultural and horticultural crop production. The ability of UAV-based sensing technologies to provide high spatial (<1 m) and temporal (on-demand) resolution data facilitates monitoring of individual plants over time and can provide essential information about health, yield, and growth in a timely and quantifiable manner. Such applications would be beneficial for cropped banana plants due to their distinctive growth characteristics. Limited studies have employed UAV data for mapping banana crops and to our knowledge only one other investigation features multi-temporal detection of banana crowns. The purpose of this study was to determine the suitability of multiple-date UAV-captured multi-spectral data for the automated detection of individual plants using convolutional neural network (CNN), template matching (TM), and local maximum filter (LMF) methods in a geographic object-based image analysis (GEOBIA) software framework coupled with basic classification refinement. The results indicate that CNN returns the highest plant detection accuracies, with the developed rule set and model providing greater transferability between dates (F-score ranging between 0.93 and 0.85) than TM (0.86–0.74) and LMF (0.86–0.73) approaches. The findings provide a foundation for UAV-based individual banana plant counting and crop monitoring, which may be used for precision agricultural applications to monitor health, estimate yield, and to inform on fertilizer, pesticide, and other input requirements for optimized farm management.
  • Towards sustainable circular brine reclamation using seawater reverse osmosis, membrane distillation and forward osmosis hybrids: An experimental investigation

    Son, Hyuk Soo; Soukane, Sofiane; Lee, Junggil; Kim,Youngjin; Kim, Young-Deuk; Ghaffour, NorEddine (Journal of Environmental Management, Elsevier BV, 2021-05-27) [Article]
    Desalination and wastewater treatment technologies require an effective solution for brine management to ensure environmental sustainability, which is closely linked with efficient process operations, reduction of chemical dosages, and valorization of brines. Within the scope of desalination brine reclamation, a circular system consisting of seawater reverse osmosis (SWRO), membrane distillation (MD), and forward osmosis (FO) three-process hybrid is investigated. The proposed design increases water recovery from SWRO brine (by MD) and dilutes concentrated brine to seawater level (by FO) for SWRO feed. It ultimately reduces SWRO process brine disposal and improves crystallization efficiency for a zero-liquid discharge application. The operating range of the hybrid system is indicated by a seawater volumetric concentration factor (VCF) ranging from 1.0 to 2.2, which covers practical and sustainable operation in full-scale applications. Within the proposed VCF range, different operating conditions of the MD and FO processes were evaluated in series with concentrated seawater as well as real SWRO brine from a full-scale desalination plant. Water quality and membrane surface were analyzed before and after experiments to assess the impact of the SWRO brine. Despite their low concentration (0.13 mg/L as phosphorous), antiscalants present in SWRO brine alleviated the flux decline in MD operations by 68.3% compared to operations using seawater concentrate, while no significant influence was observed on the FO process. A full spectrum of water quality analysis of real SWRO brine and Red Sea water is made available for future SWRO brine reclamation studies. The operating conditions and experimental results have shown the potential of the SWRO-MD-FO hybrid system for a circular brine reclamation.
  • Solar Seawater Distillation by Flexible and Fully Passive Multistage Membrane Distillation

    Wang, Wenbin; Shi, Yusuf; Zhang, Chenlin; Li, Renyuan; Wu, Mengchun; Zhuo, Sifei; Aleid, Sara; Wang, Peng (Nano Letters, American Chemical Society (ACS), 2021-05-27) [Article]
    Solar-assisted distillation is considered promising to solve the freshwater supply for off-grid communities. In this work, a passive and flexible multistage membrane distillation (F-MSMD) device is devised to produce freshwater via solar distillation with the latent heat of vapor condensation being recycled to enhance its energy efficiency. By designing a siphon effect, source water is continuously wicked into the evaporation layer and the concentrated brine flows out of the device before reaching saturation, which successfully solves the otherwise challenge of salt accumulation inside the device. To achieve such siphon flow, the recycled paper is prepared from spent copy paper and used as the evaporation layer for efficient water delivery owing to its large pore size and high hydrophilicity. An eight-stage F-MSMD device exhibits a stable clean water production rate at 3.61 kg m<sup>-2</sup> h<sup>-1</sup> in the newly designed siphon-flow mode. This work provides a green route for designing a solar-assisted distillation device.
  • Microscopy techniques applied to submicron characterization of oilfield produced water

    Medina, Sandra Constanza; Anjum, Dalaver H.; Behzad, Ali Reza; Vilagines, Regis D.; Tabatabai, S. Assiyeh Alizadeh; Leiknes, TorOve (Journal of Petroleum Science and Engineering, Elsevier BV, 2021-05-26) [Article]
    Produced water (PW) and formation water are complex mixtures of hydrocarbons and water produced at oil and gas upstream facilities. Submicron oil droplets represent a multitude of issues affecting the performance of downstream advanced water treatment processes, such as micro and ultra-filtration processes. Conventional de-oiling technologies do not efficiently remove submicron oil droplets in PW. An accurate characterization of submicron oil droplets and contaminants is required to improve PW treatment technology. In this study, a methodology for visualization and quantification of submicron oil droplets size distribution (DSD), using optical and electron microscopy techniques, was developed. Various microscopy techniques were evaluated, including epifluorescence microscopy (EpiFM), confocal laser scanning microscopy (CLSM), cryogenic scanning and transmission electron microscopy (cryo-SEM and cryo-TEM, respectively). Synthetic PW was used to improve and standardize the sample preparation and characterization methodology. The improved methodology was then tested with two PW samples from different oilfields in the Middle East region. Two methods were developed for the determination of DSD in oilfield PW samples. The first method is suitable for highly polydisperse PW samples with oil droplets larger than 250 nm. This method is based on using low-temperature agarose to immobilize the samples, avoiding coalescence, and allowing clear visualization of the oil droplets at high magnification in EpiFM. The second method is suitable for concentrated PW samples and oil droplets as small as 20 nm in size. This method is based on cryo-TEM with plunge freezing and without the use of agarose for sample immobilization. The agarose-immobilization technique was also applied for sample preparation in cryo-SEM. Cryo-SEM fixation by high-pressure freezing (HPF) preserved the morphology of oil droplets in synthetic oil-concentrated samples and allowed its visualization in a wide range of sizes from 50 nm up to 20 μm.
  • Generate DNA filaments with control using drop impact method

    Yang, Zi Qiang; Zhang, Peng; Shi, Meng; Al Julaih, Ali; Tian, Yuansi; Mishra, Himanshu; Di Fabrizio, Enzo; Thoroddsen, Sigurdur T (Submitted to MNE2021 - 47th international conference on Micro and Nano Engineering, 2021-05-26) [Preprint]
  • Global sensitivity analysis of crop yield and transpiration from the FAO-AquaCrop model for dryland environments

    Lu, Yang; Chibarabada, Tendai P.; McCabe, Matthew; De Lannoy, Gabriëlle J.M.; Sheffield, Justin (Field Crops Research, Elsevier BV, 2021-05-25) [Article]
    The application of crop models towards improved local scale prediction and precision management requires the identification and description of the major factors influencing model performance. Such efforts are particularly important for dryland areas which face rapid population growth and increasing constraints on water supplies. In this study, a global sensitivity analysis on crop yield and transpiration was performed for 49 parameters in the FAO-AquaCrop model (version 6.0) across three dryland farming areas with different climatic conditions. The Morris screening method and the variance-based Extended Fourier Amplitude Sensitivity Test (EFAST) method were used to evaluate the parameter sensitivities of several staple crops (maize, soybean or winter wheat) under dry, normal and wet scenarios. Results suggest that parameter sensitivities vary with the target model output (e.g., yield, transpiration) and the wetness condition. By synthesizing parameter sensitivities under different scenarios, the key parameters affecting model performance under both high and low water stress were identified for the three crops. Overall, factors relevant to root development tended to have large impacts under high water stress, while those controlling maximum canopy cover and senescence were more influential under low water stress. Parameter sensitivities were also shown to be stage-dependent from a day-by-day analysis of canopy cover and biomass simulations. Subsequent comparison with AquaCrop version 5.0 suggests that AquaCrop version 6.0 is less sensitive to uncertainties in soil properties.
  • Making Waves: Collaboration in the time of SARS-CoV-2 - rapid development of an international co-operation and wastewater surveillance database to support public health decision-making.

    Lundy, Lian; Fatta-Kassinos, Despo; Slobodnik, Jaroslav; Karaolia, Popi; Cirka, Lubos; Kreuzinger, Norbert; Castiglioni, Sara; Bijlsma, Lubertus; Dulio, Valeria; Deviller, Geneviève; Lai, Foon Yin; Alygizakis, Nikiforos; Barneo, Manuela; Baz-Lomba, Jose Antonio; Béen, Frederic; Cíchová, Marianna; Conde-Pérez, Kelly; Covaci, Adrian; Donner, Erica; Ficek, Andrej; Hassard, Francis; Hedström, Annelie; Hernandez, Félix; Janská, Veronika; Jellison, Kristen; Hofman, Jan; Hill, Kelly; Hong, Pei-Ying; Kasprzyk-Hordern, Barbara; Kolarević, Stoimir; Krahulec, Jan; Lambropoulou, Dimitra; de Llanos, Rosa; Mackuľak, Tomáš; Martinez-García, Lorena; Martínez, Francisco; Medema, Gertjan; Micsinai, Adrienn; Myrmel, Mette; Nasser, Mohammed; Niederstätter, Harald; Nozal, Leonor; Oberacher, Herbert; Očenášková, Věra; Ogorzaly, Leslie; Papadopoulos, Dimitrios; Peinado, Beatriz; Pitkänen, Tarja; Poza, Margarita; Rumbo-Feal, Soraya; Sánchez, Maria Blanca; Székely, Anna J; Soltysova, Andrea; Thomaidis, Nikolaos S; Vallejo, Juan; van Nuijs, Alexander; Ware, Vassie; Viklander, Maria (Water research, Elsevier BV, 2021-05-20) [Article]
    The presence of SARS-CoV-2 RNA in wastewater was first reported in March 2020. Over the subsequent months, the potential for wastewater surveillance to contribute to COVID-19 mitigation programmes has been the focus of intense national and international research activities, gaining the attention of policy makers and the public. As a new application of an established methodology, focused collaboration between public health practitioners and wastewater researchers is essential to developing a common understanding on how, when and where the outputs of this non-invasive community-level approach can deliver actionable outcomes for public health authorities. Within this context, the NORMAN SCORE "SARS-CoV-2 in sewage" database provides a platform for rapid, open access data sharing, validated by the uploading of 276 data sets from nine countries to-date. Through offering direct access to underpinning meta-data sets (and describing its use in data interpretation), the NORMAN SCORE database is a resource for the development of recommendations on minimum data requirements for wastewater pathogen surveillance. It is also a tool to engage public health practitioners in discussions on use of the approach, providing an opportunity to build mutual understanding of the demand and supply for data and facilitate the translation of this promising research application into public health practice.
  • Interactions between model organic compounds and metal oxides

    Zaouri, Noor A.; Gutierrez, Leonardo; Benedetti, Marc F.; Croue, Jean Philippe (Colloids and Surfaces A: Physicochemical and Engineering Aspects, Elsevier BV, 2021-05-20) [Article]
    Because of their mechanical, thermal, and chemical resistance, ceramic materials are suitable for challenging water treatments, where different metal oxides (MeO) have been tested as active layers. However, organic fouling is a major drawback impacting its performance. Organics adsorb onto the membrane surface and into their pores during long-term operation, resulting in irreversible fouling. This investigation focussed on the interfacial interactions between model organic acids and MeO to obtain a fundamental understanding of the adsorption phenomena. Batch adsorption experiments of a series of small molecular weight, oxygenated, aromatic organic acids were performed with Al2O3, TiO2, and ZrO2 particles, at pH 4.2 and 7.6. The adsorption of simple acids was described by the Langmuir model and exhibited a strong dependence on the relative abundance of carboxyl groups, aliphaticity/aromaticity, alkyl chain length, and presence of hydroxyl groups. The adsorption of model compounds was higher at low pH and decreased with increasing pH. The difference in Al2O3, TiO2, and ZrO2 surface characteristics, as evidenced by TEM, XRD, and BET, led to differences in the adsorption density. The results obtained with these well-defined organic structures will assist in better understanding the interfacial interactions between complex natural organic matter molecules and MeO of different characteristics.
  • Experimental and normalized sensitivity based numerical analyses of a novel humidifier-assisted highly efficient indirect evaporative cooler

    Jamil, Muhammad Ahmad; Xu, Ben Bin; Dala, Laurent; Sultan, Muhammad; Jie, Lin; Shahzad, Muhammad Wakil (International Communications in Heat and Mass Transfer, Elsevier BV, 2021-05-18) [Article]
    Indirect evaporative cooling technology has emerged as an energy-efficient, low-cost, and sustainable alternative to conventional air conditioning systems for space cooling. This is because of its significant (40–50%) energy-saving potential compared to ventilation, vapor compression cooling, and desiccant cooling systems. The current paper presents a novel humidifier-assisted regenerative indirect evaporative cooler that eliminates the use of hydrophilic surfaces within the system and mitigates the fouling propensity and water management issues. A generic cell of the proposed system is fabricated and tested for different operating scenarios along with the uncertainty propagation analysis. Thereafter, a normalized sensitivity analysis is performed to identify the most influential parameters on the cooler performance. The experimental data shows an effective cooling performance with a temperature drop of 20 °C of outdoor air and cooling capacity of 175 watts of 1800 mm × 300 mm generic cell. The cooling coefficient of performance was calculated as 44 and maximum effectiveness of 83.82% for the proposed configuration. The sensitivity analysis reveals scaling trends of the coefficient of performance in the following order of primary air inlet temperature > primary air outlet temperature > primary air velocity and the cooler effectiveness as secondary air outlet temperature > primary air inlet temperature > primary air humidity > primary air outlet.
  • The impact of different types of high surface area brush fibers with different electrical conductivity and biocompatibility on the rates of methane generation in anaerobic digestion.

    Baek, Gahyun; Rossi, Ruggero; Saikaly, Pascal; Logan, Bruce E (The Science of the total environment, Elsevier BV, 2021-05-18) [Article]
    The addition of electrically conductive materials may enhance anaerobic digestion (AD) efficiency by promoting direct interspecies electron transfer (DIET) between electroactive microorganisms, but an equivalent enhancement can also be achieved using non-conductive materials. Four high surface area brush materials were added to AD reactors: non-conductive horsehair (HB) and polyester (PB), and conductive carbon fiber (CB) and stainless steel (SB) brushes. Reactors with the polyester material showed lower methane production (68 ± 5 mL/g CODfed) than the other non-conductive material (horsehair) and the conductive (graphite or stainless steel) materials (83 ± 3 mL/g CODfed) (p < 0.05). This difference was due in part to the higher biomass concentrations using horsehair or carbon (135 ± 43 mg) than polyester or stainless steel or materials (26 ± 1 mg). A microbial community analysis indicated that the relative abundance of electroactive microorganisms was not directly related to enhanced AD performance. These results show that non-conductive materials such as horsehair can produce the same AD enhancement as conductive materials (carbon or stainless steel). However, if the material, such as polyester, does not have good biomass retention, it will not enhance methane production. Thus, electrical conductivity alone was not responsible for enhancing AD performance. Polyester, which has been frequently used as a non-conductive control material in DIET studies, should not be used for this purpose due to its poor biocompatibility as shown by low biomass retention in AD tests.
  • Role of phosphate and humic substances in controlling calcium carbonate scaling in a groundwater reverse osmosis system

    Mangal, M. Nasir; Salinas-Rodriguez, Sergio G.; Blankert, Bastiaan; Yangali-Quintanilla, Victor A.; Schippers, Jan C.; Van Der Meer, Walter G.J.; Kennedy, Maria D. (Journal of Environmental Chemical Engineering, Elsevier BV, 2021-05-14) [Article]
    The role of phosphate and humic substances (HS) in preventing calcium carbonate scaling and their impact on antiscalant dose was investigated for a reverse osmosis (RO) system treating anaerobic groundwater (GW) (containing 2.1 mg/L orthophosphate and 6-8 mg/L HS). Experiments were conducted with the RO unit (treating anaerobic GW), and with a once-through lab-scale RO system (operating with artificial feedwater). Additionally, (batch) induction time (IT) measurements were performed with, i) real RO concentrate, and ii) artificial RO concentrates in the presence and absence of phosphate and HS. It was found that at 80% recovery (Langelier saturation index (LSI) 1.7), calcium carbonate scaling did not occur in the RO unit when the antiscalant dose was lowered from 2.2 mg/L (supplier's recommended dose) to 0 mg/L. The IT of the real RO concentrate, without antiscalant, was longer than 168 h, while, at the same supersaturation level, the IT of the artificial concentrate was approximately 1 h. The IT of the artificial concentrate increased to 168 h with the addition of 10 mg/L of phosphate, humic acid (HA), and fulvic acid (FA). Furthermore, in the lab-scale RO tests, the normalized permeability (Kw) of the membrane decreased by 20% in 2 h period when fed with artificial concentrate of 80% recovery containing no phosphate, whereas, with phosphate, no decrease in Kw was observed in 10 h period. These results indicate that phosphate and HS present in the GW prevented calcium carbonate scaling in the RO unit and reduced the use of commercial (synthetic) antiscalants.
  • Treatment of high-strength synthetic textile wastewater through anaerobic osmotic membrane bioreactor and effect of sludge characteristics on flux

    Malik, Surraya Mehbub; Nawaz, Muhammad Saqib; Ali, Muhammad; Manzoor, Kamran; Khan, Sher Jamal; Ghaffour, NorEddine (Environmental Quality Management, Wiley, 2021-05-13) [Article]
    The anaerobic osmotic membrane bioreactor (AnOMBR) system was evaluated for the treatment of high-strength synthetic textile wastewater. The chemical oxygen demand (COD) concentration was above 3,000 mg/L and color above 1,300 Pt-Co in the synthetic textile wastewater. The study was divided into six cycles of roughly nine days each. Mono ammonium phosphate with 1 M concentration was used as draw solution. Average COD and color removal efficiencies from anaerobic bioreactor were 57% ± 5% and 43.7% ± 6%, respectively; however, in OMBR permeate, these parameters were improved to 91% ± 4% and 91% ± 2%, respectively. After each cycle, membrane cleaning was performed using osmotic backwashing for 3 hours, which produced flux recovery values between 88% and 61% from cycle 2 to cycle 6, respectively. High mixing speed of the stirrer bar (600 rpm) in the bioreactor produced a greater shear force, causing a reduction in average sludge particle size from 10 to 3.5 μm. It increased the release of soluble microbial products and extra polymeric substances to cause an initial flux decline from 3.3 to 2.2 LMH from cycle 1 to cycle 6. The study proved AnOMBR as a promising technology for high-strength synthetic textile wastewater treatment.
  • Attached-growth configuration outperforms continuously stirred tank anaerobic membrane bioreactors in alleviating membrane biofouling

    Cheng, Hong; Zhou, Jianqiang; Hong, Pei-Ying (Environmental Research, Elsevier BV, 2021-05-12) [Article]
    Biofouling impedes the performance of anaerobic membrane bioreactors (AnMBR). Two reactors, one as an up-flow attachment-growth AnMBR (UA-AnMBR) configuration, and the other, as a continuously stirred AnMBR (CS-AnMBR) were evaluated for differences in membrane fouling rate. TMP increment in UA-AnMBR was slower than CS-AnMBR, although both reactors had similar COD removal efficiency (ca. > 96%). Slower fouling rate for UA-AnMBR was related to lower total and viable cells, and thereby microbial activity compared to that in CS-AnMBR. Acinetobacter and Methanobacterium that played keystone roles in anaerobic biofilm formation were not consistently prevalent on the membranes connected to UA-AnMBR. This is in contrast to both Acinetobacter and Methanobacterium consistently prevalent on the membranes connected to CS-AnMBR. The findings suggest that UA-AnMBR can alleviate membrane biofouling through changes in microbial activity and profile dynamics, and would be a suitable reactor configuration to adopt to achieve an efficient AnMBR for municipal wastewater treatment.
  • Nano/micro plastics – Challenges on quantification and remediation: A review

    Enfrin, Marie; Hachemi, Cyril; Hodgson, Peter D.; Jegatheesan, Veeriah; Vrouwenvelder, Johannes S.; Callahan, Damien L.; Lee, Judy; Dumée, Ludovic F. (Journal of Water Process Engineering, Elsevier BV, 2021-05-11) [Article]
    Nano and micro plastics (NP/MPs) represent one of the most challenging classes of micro-pollutants, with occurrence across all ecosystems and size distributions ranging from the nanometre to the millimetre scale. These broad composition and size distribution ranges limit the efficiency of detection methods, often inherently focused on a single and narrow class of NP/MPs sizes. In addition to their demonstrated native toxicity, NP/MPs may act as efficient carriers of pollutants and pathogens onto their surface, facilitating the transfer and penetration of other classes of hazardous materials. This comprehensive review presents the key challenges related to soil, air and water NP/MPs: (i) sampling and extraction, (ii) using defined synthetic NP/MPs for spiking environmental samples and for model studies, and (iii) characterisation. A major challenge discussed in this paper relates to the lack of relevant characterisation strategies for the NP/MPs materials, enabling simultaneous identification, quantification and generation of statistical size distributions. This critical discussion ends with a series of well-informed propositions to support the systematic assessment of the impact of NP/MPs materials, spanning from materials science and characterisation, as well as environmental and chemical engineering.

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