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This research explores the enhancement of polyethersulfone (PES) membranes through the incorporation of chitosan derived from the lignicolous fungus Ganoderma sp. Utilizing wet phase inversion and solution casting techniques, chitosan was successfully integrated into the PES matrix, as confirmed by Fourier Transform Infrared Spectroscopy (FT-IR), which indicated a high deacetylation degree of 75.7%. The incorporation of chitosan significantly increased the membrane hydrophilicity, as evidenced by a reduction in the water contact angle and a substantial improvement in pure water permeability, from 17.9 L m-2 h-1 bar-1 to 27.3 L m-2 h-1 bar-1. The membrane anti-fouling properties were also notably enhanced, with the Flux Recovery Ratio (FRR) increasing from approximately 60–80%. Moreover, the chitosan-modified PES/CS membrane, particularly at a 5% chitosan concentration, demonstrated exceptional efficacy in pollutant removal, achieving over 90% elimination of total suspended solids, cadmium (Cd), and lead (Pb), alongside a 79% reduction in color during the treatment of textile wastewater. [ABSTRACT FROM AUTHOR]

Biocatalytic membranes have great potential in various industrial sectors, with the immobilization of enzymes being a crucial stage. Immobilizing enzymes through covalent bonds is a complex and time-consuming process for large-scale applications. Polydopamine (PDA) offers a more sustainable and eco-friendly alternative for enzyme immobilization. Therefore, surface modification with polydopamine as mussel-inspired antifouling coatings has increased resistance to fouling. In this study, α-amylase enzyme was covalently bound to a bioactive PDA-coated polyethersulfone (PES) membrane surface using cyanuric chloride as a linker. The optimal activity of α-amylase enzyme immobilized on PES/PDA membrane was obtained at temperature and pH of 55°C and 6.5, respectively. The immobilized enzyme can be reused up to five reaction cycles with 55 % retention of initial activity. Besides, it maintained 60 % of its activity after being stored for five weeks at 4°C. Additionally, the immobilized enzyme demonstrated increased Michaelis constant and maximum velocity values during starch hydrolysis. The results of the biofouling experiment of various membranes in a dead-end cell demonstrated that the PES membrane's water flux increased from 6722.7 Lmh to 7560.2 Lmh after PDA modification. Although α-amylase immobilization reduced the flux to 7458.5 Lmh due to enhanced hydrophilicity, compared to unmodified membrane. The findings of this study demonstrated that the membrane produced through co-deposition exhibited superior hydrophilicity, enhanced coating stability, and strong antifouling properties, positioning it as a promising candidate for industrial applications. [Display omitted] • α-Amylase was covalently immobilized onto polydopamine-functionalized polyethersulfone membrane. • Surface modification with polydopamine generated a mussel-inspired coating to inhibit fouling. • The immobilization technique effectively preserved the activity of α-amylase enzyme. • The biocatalyst membrane exhibited superior stability and strong antifouling properties. [ABSTRACT FROM AUTHOR]

This study examines the polyvinylidene fluoride (PVDF) ultrafiltration membrane impregnated with the copper acetate monohydrate/nickel chloride/thiourea (CuNit) nanoparticle through its physical properties, chemical properties, water flux, humic rejection, and antifouling properties against peat water. The ultrafiltration membrane was fabricated via phase inversion by blending CuNit nanoparticles (1, 3, and 5 wt/wt PVDF %) and PVDF (16 wt %) in N‐Methyl‐2‐pyrrolidone (NMP, 42 wt %) as the solvent. The humic rejection and fouling test are conducted using peat water collected from the Beladin water treatment plant. As a result, M03, which has 1 wt/wt PVDF % of CuNit nanoparticle, gives a better result of pure water flux, humic rejection, and fouling recovery rate with a value of 82 L/m2 h, 93 %, and 40 % compared to pristine PVDF membrane. The fouling of M03 recorded a low total rate of fouling (76 %) that is caused by high reversible fouling and low irreversible fouling with a value of 0.16 and 0.59, respectively, compared to the pristine PVDF membrane. In conclusion, due to the agglomeration that occurs in the further addition of CuNit nanoparticles, coating or encapsulation must be done to improve the stability of nanoparticles and reduce the leach‐out problem as well as provide a good distribution between the nanoparticle and casting solution during the membrane fabrication. [ABSTRACT FROM AUTHOR]

The increasing environmental concerns of conventional antifouling coatings have led to the exploration of novel and sustainable solutions to address the biofouling caused by Limnoperna fortunei. As a rapidly expanding invasive species, the fouling process of Limnoperna fortunei is closely associated with microbial fouling, posing significant threats to the integrity of aquatic infrastructure and biodiversity. This review discusses recent progress in the development of non-toxic, eco-friendly antifouling coatings that are designed to effectively resist biofouling without using toxic chemicals. Recent research has focused on developing novel non-toxic coatings that integrate natural bioactive components with advanced material technologies. These formulations not only meet current environmental standards and exhibit minimal ecological impact, but also possess significant potential in preventing the attachment, growth, and reproduction of Limnoperna fortunei. This review aims to provide scientific guidance by proposing effective and sustainable solutions to address the ecological challenges presented by Limnoperna fortunei. The insights gained from current research not only reveal novel antifouling methods, but also identify key areas for further investigation aimed at enhancing performance and environmental compatibility. [ABSTRACT FROM AUTHOR]

Fouling, the accumulation of undesirable material on manufacturing equipment surfaces, poses a pervasive challenge in industrial processes. In the food industry, the complex interactions among these compounds can give rise to stubborn deposits that deviate from conventional cleaning protocols. In this work, the forces and removal mechanisms of model fouling agents composed of mixtures of starch, whey protein, and lard deposited on solid surfaces of relevant industrial interest (i.e. stainless steel, aluminium, and PTFE) are investigated using a multi-length scale approach, involving milli-manipulation and a lab-simulated Clean-In-Place (CIP) system. The forces involved in the removal process, the types of failure observed when the deposits are subjected to shear stress (adhesive, mixed, or cohesive), and the performance of the CIP system are systematically analysed as a function of the cleaning treatments applied. For stainless steel surfaces, alkaline treatment seems to facilitate the cleaning of lard and starch deposits, while the whey foulant removal tends to be more effective using hot water under the conditions tested. Hot water is effective for stainless steel and PTFE surfaces, reducing the mechanical shear stress required, while the alkaline treatment demonstrated superior efficacy for aluminium surfaces. These findings emphasise the importance of customising cleaning protocols for CIP optimisation. [ABSTRACT FROM AUTHOR]

The Electrodialysis with Filtration Membrane (EDFM) system has shown promise in juice enrichment, but further optimization is needed. This study evaluated the effect of processing duration (3 and 6 h) on juice composition, process efficiency, and membrane fouling. Results demonstrated a significant impact of processing time on juice composition, especially anthocyanin and mineral content. Two anthocyanin-depleted juices (−18.94% and −30.70%) and two anthocyanin-enriched juices (26.21% and 44.21%) were produced. Similar energy (1512.13 Wh/g of anthocyanins) was required to migrate equivalent amounts of anthocyanins over both time periods, with no impediment due to fouling observed, although the system's resistance increased (2.5-fold after 3 h, 3.2-fold after 6 h). Membrane fouling was characterized through conductivity, thickness, ATR-FTIR, SEM-EDX, and foulant identification. Minimal anthocyanin accumulation occurred on cation-exchange membranes (CEM), while anthocyanins and PACs concentrated within the filtering layer of filtration membranes (FM). However, fouling did not increase with longer processing. Structural alterations were noted in anion-exchange membranes (AEMs), suggesting instability under high electric fields. Overall, EDFM effectively enriched cranberry juice with anthocyanins, but further research is necessary to address AEM degradation under limiting current density conditions. [ABSTRACT FROM AUTHOR]

Multi-layer membrane filtration is a widely used technology for separating and purifying different components of a liquid mixture. This technique involves passing the liquid mixture through a series of membranes with decreasing pore sizes, which allows for the separation of different components according to their molecular size. This study investigates the filtration process of a fluid through a two-dimensional porous medium designed for seawater desalination. The focus is on understanding the impact of various parameters such as the coefficient of friction, velocity, and the number of layers on filtration efficiency. The results reveal that the number of layers plays a crucial role in desalination, with an increase in layers leading to enhanced filtration quality, following a power law relationship. The study explores the influence of the coefficient of friction on filtration performance, emphasizing its significant effect on the number of particles filtered over time. Additionally, the role of the initial velocity in filtration efficiency is examined, showing distinct effects at both high and low velocities. Biofouling is identified as a factor influencing filtration, with an initial increase in filtered particles followed by a decline due to particle accumulation in pores. [ABSTRACT FROM AUTHOR]

The diverse composition of milk throughout the year can potentially impact subsequent processing in the dairy industry and the quality of the final products. This fluctuation in milk composition is influenced by direct and indirect factors like seasonal variability. Milk powders are produced through a complex process and are intended for various end uses and require consistency of composition along with desirable physical and functional properties. This review aims to report technical challenges and limitations related to the functional and quality characteristics of milk powder and highlight recent approaches used to mitigate seasonally related differences in milk composition. [ABSTRACT FROM AUTHOR]

A hull and propeller biofouling assessment framework is presented and demonstrated using a bulk carrier as a case study corresponding to an operational period of two and a half years. The aim is to support the decision-making process for optimizing maintenance related to hull and propeller cleaning actions. For the degradation assessment, an appropriate key performance indicator is defined comparing the expected shaft power required with the measured power under the same operational conditions. The power prediction models are data-driven based on machine learning algorithms. The process includes feature engineering, filtering, and data smoothing, while an evaluation of regression algorithms of the decision tree family is performed. The extra trees algorithm was selected, presenting a mean absolute percentage error of 1.1%. The analysis incorporates two prediction models corresponding to two different approaches. In the first, the model is employed as a reference performance baseline representing the clean vessel. When applied to a dataset reflecting advanced stages of biofouling, an average power increase of 11.3% is predicted. In the second approach, the model entails a temporal feature enabling the examination of scenarios at different points in time. Considering synthetic data corresponding to 300 days since hull cleaning, it was derived that the fouled vessel required an average 20.5% increase in power. [ABSTRACT FROM AUTHOR]

In this study, the combination of the conventional membrane bioreactor (MBR) process with attached growth system using moving bed (MBMBR) and fixed bed (FBMBR) for simultaneous removal of organic carbon, nitrogen, and phosphorus from wastewater was carried out at a pilot-scale application. The effluent was monitored daily for COD, NO3, PO4, and pH concentrations to achieve COD removal and nitrogen and phosphorus stabilization. After achieving equilibrium, sampling was done twice a week from the raw wastewater tank, aerated reactor, and effluent. Various parameters including MLSS, MLVSS, SVI, nitrate, and total phosphorus were measured by standard methods and the effects of variables such as retention time and optimal conditions were investigated in the MBMBR and FBMBR reactors. The results showed that the membrane fouling rate in the MBMBR reactor was higher than that in the FBMBR reactor; and the nitrogen and phosphorus removal efficiency in the FBMBR reactor was significantly higher than that in the MBMBR reactor. The combined MBR process with a fixed and moving bed depicted a suitable capability for removing organic carbon, nitrogen, and phosphorus. It was found that the membrane bioreactors benefited from a higher efficiency, especially the FBMBR reactor, in removing parameters such as phosphorus, nitrogen, and organic matter compared to the MBMBR reactor. In general, it can be concluded that the type of biofilm carrier medium affects membrane fouling and sludge filterability. [ABSTRACT FROM AUTHOR]

This work proposes an octopus‐inspired smart skin for fouling release. The skin consists of twisted spiral artificial muscles (TSAMs) embedded between two layers of elastomer. Upon electro‐thermal actuation, TSAMs undergo vertical displacement (similarly to octopus' papillae dermal muscles) and mechanically deform the top layer of the skin where the biofilm is attached. The release is achieved by generating a critical strain on the skin's top layer. In this paper, a physics‐based mechanical model is proposed to describe the fouling release mechanism of the smart skin. The model relates the critical strain to the mechanical properties of the biofilm, as well as the mechanical and electro‐thermal properties of the TSAMs. The model is experimentally validated, and a robust controller is implemented to achieve the desired critical strain and then perform release for two different types of biofilms: bacterial‐based Escherichia coli and diatom‐based Amphora coffeaeformis. [ABSTRACT FROM AUTHOR]

Fouling in continuous reactors presents a significant challenge in the process intensification of specialty polymers. While in continuous stirred tank reactors (CSTRs) fouling is minimal, tubular reactors experience severe fouling, sometimes leading to complete blockage. Therefore, it is crucial to understand process and design conditions contributing to deposit formation. In this work, the impact of geometry, mixing elements, novel coatings, and ultrasonic waves are tested on tubular reactors for the polymerization of polyvinylpyrrolidone. [ABSTRACT FROM AUTHOR]

In contrast to expectations, even buoyant microplastics like polyethylene and polypropylene are found at high concentrations in deep sediment traps and deep-sea sediments. To explain the presence of such buoyant microplastic particles at great ocean depths, several vertical transport mechanisms are under discussion with biofouling as one of the most referred. Biofouling is thought to increase the density of microplastic particles to the point that they sink to the deep sea, but this has mostly been shown on large microplastic particles ≥ 1 mm. However, although microplastics are defined as particles between 1 and 5000 μm, most microplastics are < 100 μm. In the ocean plastic particles continuously fragment, converting each "large" particle into several "small" particles, and particle abundance increases drastically with decreasing size. We argue that biofouling is not a reasonable transport mechanism for small microplastic particles ≤ 100 μm, which form the majority of microplastics. Biofilm density depends on its community and composition. A biofilm matrix of extracellular polymeric substances and bacteria has a lower density than seawater, in contrast to diatoms or large organisms like mussels or barnacles. We suggest that a small microplastic particle cannot host a biofilm community consisting of the heavy organisms required to induce sinking. Furthermore, to reach the deep sea within a reasonable timespan, a microplastic particle needs to sink several meters per day. Therefore, the excess density has to not only exceed that of seawater, but also be large enough to enable rapid sinking. We thus argue that biofouling cannot be an efficient vertical transport mechanism for small microplastic. However, biofouling of small microplastic may promote the likelihood of its incorporation into sinking marine snow and increase the probability of its ingestion, allowing its transport to depth. [ABSTRACT FROM AUTHOR]

The primary approach to managing biofouling in industrial water systems involves the large‐scale use of biocides. It is well‐established that biofilms are 'cell factories' that release planktonic cells even when challenged with antimicrobials. The effect of isothiazolinone on the metabolic activity and biomass of mixed Pseudomonas biofilms was monitored in real‐time using the CEMS‐BioSpec system. The exposure of biofilms to the minimum inhibitory concentration (1.25 mg L−1) of biocide did not impact planktonic cell production (log 7.5 CFU mL−1), while whole‐biofilm metabolic activity and biomass accumulation increased. Only the maximum biocide concentration (80 mg L−1) resulted in a change in planktonic cell yields and temporal inhibition of biofilm activity and biomass, a factor that needs due consideration in view of dilution in industrial settings. Interfacing the real‐time measurement of metabolic activity and biomass with dosing systems is especially relevant to optimizing the use of biocides in industrial water systems. [ABSTRACT FROM AUTHOR]

The performance of heat pump systems for heating and cooling heavily relies on the thermal conditions of their reservoirs. This study introduces a novel thermal reservoir, detailing a 2017 project where the Municipality of Stavanger installed a heat exchanger system on the wall of a main wastewater tunnel beneath the city center. It provides a comprehensive account of the system's design, installation, and performance, and presents an Artificial Neural Network (ANN) model that predicts heat pump capacity, electricity consumption, and outlet temperature across seasonal variations in wastewater temperatures. By integrating domain knowledge with the ANN, this study demonstrates the model's capability to detect anomalies in heat pump operations effectively. The network also confirms the consistent performance of the heat exchangers from 2020 to 2024, indicating minimal fouling impacts. This study establishes wastewater heat exchangers as a safe, effective, and virtually maintenance-free solution for heat extraction and rejection. [ABSTRACT FROM AUTHOR]

Micro heat exchangers improve heat and mass transfer compared to conventional heat exchangers, enabling more energy‐efficient applications. However, their sensitivity to fouling limits broader industrial application. This approach presents a combined investigation of fouling and cleaning in microscale heat exchangers using two test rigs. Individual sets of analysis methods are developed to improve the understanding of heat and mass transfer on the microscale. In addition to known methods, such as pressure loss analysis, newly developed and established image analysis techniques are used to monitor fouling and cleaning. Based on the presented methods, it is possible to predict the initial position of thermally induced fouling and to demonstrate the applicability of automated cleaning on the microscale. [ABSTRACT FROM AUTHOR]

The applicability of a fluidically heated spinning disk apparatus (SDA) was tested for investigating the influence of the tangential velocity on the deposition of particulate material systems, in particular on latex particles. First, the SDA was characterized for particle fouling investigations with micro glass beads as a model system, then, a first series of tests was carried out with a real material system, a vinyl acetate/Versa 10 copolymer. Experiments were performed for a duration of 1 h and a tangential velocity up to 0.3 m s−1. The fouling process was characterized by the local fouling layer thickness and the calculated local mass‐based fouling resistance. A decrease in fouling resistance along the radius of the rotating disk as a function of the tangential velocity was observed. [ABSTRACT FROM AUTHOR]

Fouling mitigation provides many challenges in process equipment, especially in heat exchangers. In this work, the fouling behaviors of two polymers are compared to 1.4301 stainless steel (SS) in calcium sulfate solutions. An experimental setup that allows to classify the materials quickly and under varying process conditions is used to determine the fouling behavior. Results are compared to a screening apparatus which can test up to three materials simultaneously. Finally, the cleaning behavior of all three materials is investigated. Results show that polyether ether ketone (PEEK) is superior to SS in mitigating fouling and is easier to clean; however, polyether ether ketone with 30 % talcum (TKT) is not. This is attributed to the surface roughness of the materials. [ABSTRACT FROM AUTHOR]

Fouling is a challenge in many processes, especially in heat exchangers and evaporators. Even though many treatments have been developed to mitigate fouling on metallic surfaces, no standardized method exists to compare equipment based on its antifouling performance. In this work, a screening apparatus is presented, which allows to compare samples of treated metallic surfaces based on thermal fouling resistance. A parameter screening and a ranking of three differently treated metallic surfaces using two model substances, namely, whey protein concentrate (WPC) and calcium sulfate, are demonstrated. [ABSTRACT FROM AUTHOR]

Fouling in columns is a persistent challenge in the chemical process industry, leading to decreased efficiency and increased operating costs. This paper presents an investigation into fouling behavior on individual random packing elements in packed columns using computational fluid dynamics (CFD) simulations. The study aims to gain a deeper understanding of how fouling grows and impacts the flow behavior, predicting areas susceptible to fouling and providing insights for improved design. The simulation results are validated against experimental results and show good agreement. [ABSTRACT FROM AUTHOR]

Fouling on column internals leads to many malfunctions in chemical processes every year. Despite the importance for the industry, only a few systematic studies exist on the fouling of column internals. Here, a new screening test rig is presented for the rapid and easy characterization of a wide range of internals with respect to their fouling tolerance. A countercurrent of saturated NaCl/water solution and air is used to force crystallization fouling. Photographs help to identify the initial points of fouling on two random packings and provide insights into the growth of deposits. In addition, the fouling tolerance of five different trays is investigated, demonstrating that trays with larger curtain area show greater fouling tolerance. [ABSTRACT FROM AUTHOR]

The hydraulic calculation of column internals is crucial for their design. The various fouling effects (due to crystallization, particles, chemical reaction) influence the hydraulics of columns in different ways (capacity, separation efficiency). However, current hydraulic models are based on clean systems and do not consider fouling. By properly taking into account the geometrical parameters affected by fouling, the classical models can be used to calculate the state of internals as they evolve over time. [ABSTRACT FROM AUTHOR]

Unwanted deposit formation on heat and/or mass transfer surfaces (fouling) also leads to problems during operation of columns. Column fouling thus also contributes to global warming through increased energy demand and operational disturbances. The newly developed standard apparatus for investigating column fouling, which was developed as part of the SAMARA joint project funded by the BMWK, makes it possible to clarify the processes involved in the formation and prevention of fouling in columns and to take targeted countermeasures. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The marine algae Ulva spp. are commonly used as model biofouling organisms. As biofouling studies are primarily conducted using field-collected specimens, factors including species identity, seasonal availability, and physiological status can hinder the replicability of the results. To address these limitations, a protocol was developed for the on-demand laboratory culture and release of Ulva zoospores. The biofouling potential of laboratory-cultured and field-collected Ulva blades was compared using a waterjet. No significant differences were found between field and laboratory-cultured samples in either spore adhesion (before waterjet) or the proportion of spores retained after waterjet exposure. However, there was significant variability within each session type in pre- and post-waterjet exposures, indicating that spore adhesion and retention levels vary significantly among trial runs. In addition, all our laboratory cultures were Ulva Clade C (LPP complex). In contrast, our field samples contained a mix of Ulva Clade C, U. compressa clade I, and U. flexuosa Clade D. This protocol for on-demand production of Ulva spores can improve biofouling research approaches, enables comparison of results across laboratories and regions, and accelerate the development of anti-biofouling strategies. [ABSTRACT FROM AUTHOR]

Membrane fouling caused by effluent organic matter (EfOM) limits its further application in wastewater reuse. In this study, the effect of UV/chlorine pretreatment on membrane fouling was investigated in treating secondary effluent by ultrafiltration (UF) process. The relation between organic matter changes and fouling alleviation after UV/chlorine pretreatment was also studied according to the molecular weight (MW) changes in various resin fractions derived from EfOM. Results showed that UV/chlorine pretreatment effectively alleviated irreversible fouling, whereas chlorine pre-oxidation primarily mitigated reversible fouling. UV/chlorine pre-oxidation reduced 18% of reversible membrane fouling and 38% of irreversible membrane fouling at a chlorine dosage of 8 mg/L, indicating better performance in membrane fouling mitigation than chlorine pre-oxidation. UV/chlorine pre-oxidation also decreased dissolved organic matter in the UF permeate. The hydrophobic acidic (HPO-A) fraction caused dominant membrane fouling, while the hydrophilic (HPI) fraction contained most of high MW organic matter. Pre-oxidation changed the polarity of organic matter in the HPO-A fraction and decomposed the organics of high MW in the HPI fraction, which alleviated membrane fouling. These results showed that UV/chlorine pre-oxidation was a prospective pretreatment process prior to UF in wastewater reclamation. [ABSTRACT FROM AUTHOR]

The petroleum refining business consumes approximately 0.2 MMBTU/BBL of energy annually. This consumption is mitigated using heat integration techniques. However, a significant challenge in this process is fouling in the preheat train network of heat exchangers. Fouling necessitates regular cleaning, leading to substantial operational inefficiencies and costs, with annual losses estimated at nearly $16.5 billion. To address this issue, implementing a predictive maintenance model is crucial for performing maintenance at optimal periods, thereby reducing these losses. The study proposes an artificial neural network (ANN) developed using MATLAB's nntool, trained on industrial heat exchanger samples that were preprocessed in Microsoft Excel. This ANN model is designed to forecast fouling patterns in shell and tube heat exchangers. The model's accuracy and effectiveness were validated using R2 (coefficient of determination) and RMSE (root mean square error) measures. The results indicated that the EA-307 Feed-Forward Back-Propagation Neural Network (FFBPNN) model delivered satisfactory performance, with an R2 value of 0.9961. This high level of accuracy underscores the significant impact of the number of neurons on the model's predictive output. Furthermore, the model's testing on a new dataset yielded impressive results, achieving an R2 value of 0.966. This demonstrates the model's robustness and reliability in predicting fouling patterns, facilitating improved maintenance schedules, and minimizing the financial losses associated with fouling. The study highlights the potential of advanced neural network models to significantly enhance the operational efficiency of petroleum refineries by enabling more precise and timely maintenance interventions. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Xi'an Jiaotong University is the property of Editorial Office of Journal of Xi'an Jiaotong University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Biomass serves as an alternative energy solution for decarbonizing coal-fired power plants, which have been reactivated in several countries due to the global energy crisis. Oil palm waste, owing to its abundant availability, holds significant potential as a biomass fuel. This study aimed to investigate the combustion performance of various oil palm wastes in comparison to coal. Biomass combustion is associated with ash-related problems such as slagging, fouling, and corrosion, which may accelerate ash deposit acceleration, reduce heat transfer, and damage refractory equipment in boilers. Ash-related problems were evaluated using the method commonly adopted for solid fuel, including experimental drop tube furnace combustion and ash observation. The results indicate that each oil palm waste has different combustion characteristics. Palm leaves, empty fruit bunch, and palm fronds with clean probe observation have a relatively low tendency of slagging and fouling and can be recommended as biomass fuel for co-firing. However, their high alkali and iron contents need to be considered. Palm fiber has similar combustion characteristics to coal, but it has a high slagging and fouling tendencies. The palm stems with high chlorine content have a high corrosion tendency confirmed by probe observation, scanning electron microscopy, and X-ray diffraction analyses. [ABSTRACT FROM AUTHOR]

Biofouling, the accumulation of marine organisms on submerged surfaces, presents significant operational challenges across various marine industries. Traditional detection methods are labor intensive and costly, necessitating the development of automated systems for efficient monitoring. The study presented in this paper focuses on detecting biofouling on tidal stream turbine blades using camera-based monitoring. The process begins with dividing the video into a series of images, which are then annotated to identify and select the bounding boxes containing objects to be detected. These annotated images are used to train YOLO version 8 to detect biofouled and clean blades in the images. The proposed approach is evaluated using metrics that demonstrate the superiority of this YOLO version compared to previous ones. To address the issue of misdetection, a data augmentation approach is proposed and tested across different YOLO versions, showing its effectiveness in improving detection quality and robustness. [ABSTRACT FROM AUTHOR]

Membrane fouling caused by many direct and indirect triggering factors has become an obstacle to the application of membrane bioreactors (MBRs). The nonlinear relationship between those factors is subject to complex causality or affiliation, which is difficult to clarify for the diagnosis of membrane fouling. To solve this problem, this paper proposes a compressible diagnosis model (CDM) based on transfer entropy to facilitate the fault diagnosis of the root cause for membrane fouling. The novelty of this model includes the following points: Firstly, a framework of a CDM between membrane fouling and causal variables is built based on a feature extraction algorithm and mechanism analysis. The framework can identify fault transfer scenarios following the changes in operating conditions. Secondly, the fault transfer topology of a CDM based on transfer entropy is constructed to describe the causal relationship between variables dynamically. Thirdly, an information compressible strategy is designed to simplify the fault transfer topology. This strategy can eliminate the repetitious affiliation relationship, which contributes to diagnosing the root causal variables speedily and accurately. Finally, the effectiveness of the proposed CDM is verified by the measured data from an actual MBR. The results of experiments demonstrate that the proposed CDM fulfills the diagnosis of membrane fouling. [ABSTRACT FROM AUTHOR]

Biofilms are a concern for spaceflight missions, given their propensity for biofouling systems and their potential threat to astronaut health. Herein, we describe a random positioning machine-based method for growing fluorescent protein-expressing streptococcal biofilms under simulated microgravity. Biofilms can be subsequently imaged by confocal microscopy without further manipulation, minimizing disruption of architecture. This methodology could be adaptable to other bacteria, potentially standardizing biofilm growth and study under simulated microgravity. [ABSTRACT FROM AUTHOR]

Blue energy obtained by salinity gradient can be generated by mixing two saline solutions having different salt concentrations. According to researchers working in this area, about 80% of the current global electricity demand could potentially be covered by this energy source. There are basically two membrane technologies so-called pressure-retarded osmosis (PRO) and reverse electrodialysis (RED) that are capable to generate electrical energy from salinity gradient. The pressure driven PRO process is more suitable for energy generation from highly concentrated brines. However, RED is more favorable for power generation by mixing seawater and river water. In RED process, ion exchange membranes (IEMs) placed between two electrodes in a stack were employed for transport of ions. Thus, an electrical current is obtained at the electrodes by electron transport through redox reactions. This review gives an overview of RED as a pioneering technology for salinity gradient energy (SGE) generation. The review summarizes the recent improvements of IEMs employed for RED studies, membrane fouling and RED stack design. [ABSTRACT FROM AUTHOR]

Of the processes that are approved to produce synthetic kerosene for use in jet fuel, about half produce olefinic kerosene that is hydrotreated. The alkene concentration in synthetic kerosene is indirectly regulated through the thermal oxidative stability specification. Perceptions about the deleterious influence of alkenes on thermal oxidative stability suggest that olefinic kerosene must be deeply hydrogenated. The extent of olefin saturation required has economic implications. To evaluate what an acceptable alkene concentration in synthetic kerosene is, the impact of alkene concentration on the outcome of the jet fuel thermal oxidative stability test (JFTOT) performed at 325°C in accordance with the ASTM D3241 standard test method was experimentally evaluated. Model synthetic kerosene mixtures to which different concentrations of alkenes (1‐decene, α‐methylstyrene, indene) were added, as well as control samples were studied. In the concentration range investigated, up to 10 wt% 1‐decene, 5 wt% α‐methylstyrene, and 2 wt% indene did not lead to increased fouling in the JFTOT. Fouling passed through a minimum value with increasing alkene concentration and alkene concentration on its own was a poor predictor of thermal oxidative stability. Analysis of the kerosene collected after passing through the JFTOT found measurable changes in density and refractive index. Dissolved oxygen reacting during thermal oxidative stability testing was accounted for mostly in oxygen‐containing products in the kerosene boiling range, which indicated that the heavier products were mainly hydrocarbon in nature. In addition to initiation by autoxidation, the investigation also pointed to the existence of a second thermally initiated fouling pathway that does not require the presence of oxygen. [ABSTRACT FROM AUTHOR]

Commercial shipping activity plays a crucial role in the unintentional primary and secondary introduction of aquatic Non-Indigenous species (NIS), with ballast water (BW) and hull biofouling being the two major vectors of NIS transportation. The aim of this study is to identify potential high-risk donor port areas that may act as pools for NIS introduction in Saronikos Gulf, Greece. For the purpose of the study, we conducted a regional risk assessment and produced a NIS watch list based on the commercial vessel arrivals at the major ports of the Saronikos Gulf (Piraeus and Elefsis) for the period 2020–2022. In our risk analysis, we used the two most important factors for ship-mediated species introductions identified in the literature: salinity and biogeographic region of the voyage last origin ports. Then, combined with data on vessel arrivals, based on marine traffic data collected from the Marine Traffic online platform, we produced a NIS watch list for the study area. The most highrisk ports for primary introductions were found to be in the Temperate Northern Atlantic (e.g. Gemlik, Ambarli, Asyaport and Derince in Türkiye, Sines in Portugal), Western Indo-Pacific (e.g. Jeddah in Saudi Arabia, Aqaba in Jordan) and the Central Indo-Pacific (e.g. Singapore). For secondary introduction, the most high-risk voyage origin ports are located in the Levantine Sea (e.g. Limassol in Cyprus, Alexandria and Port Said in Egypt, Haifa and Ashdod in Israel, Iskenderun, Mersin and Nemrut in Türkiye), the Aegean Sea (e.g. Izmir in Türkiye) and the Ionian Sea (e.g. Marsaxlokk in Malta). Our watch list included 44 high risk and 13 medium risk NIS to be transferred to Saronikos Gulf. Of these, 38 high-risk species are already present in the Mediterranean, 6 high-risk species are absent from the Mediterranean and 18 species pose a high risk for both primary and secondary introduction. [ABSTRACT FROM AUTHOR]

Karst caves, formed by the erosion of soluble carbonate rocks, provide unique ecosystems characterized by stable temperatures and high humidity. These conditions support diverse microbial communities, including wall microbial fouling, aquatic biofilms, and planktonic communities. This study discloses the taxonomic diversity of protists in aquatic biotopes of Shulgan-Tash Cave, a culturally significant site and popular tourist destination, by 18S rRNA gene metabarcoding. Our findings reveal the rich protist communities in the cave's aquatic biotopes, with the highest diversity observed in Blue Lake at the cave entrance. In contrast, Distant Lake in the depth of the cave was inhabited by specific communities of plankton, mats, and pool fingers, which exhibited lower richness and evenness, and were adapted to extreme conditions (cold, darkness, and limited nutrients). High-rank taxa including Opisthokonta, Stramenopiles, and Rhizaria dominated all biotopes, aligning with observations from other subterranean environments. Specific communities of biotopes inside the cave featured distinct dominant taxa: amoeboid stramenopile (Synchromophyceae) and flagellates (Choanoflagellatea and Sandona) in mats; flagellates (Choanoflagellatea, Bicoecaceae, Ancyromonadida) and amoeboid protists (Filasterea) in pool fingers; flagellates (Ochromonadales, Glissomonadida, Synchromophyceae), fungi-like protists (Peronosporomycetes), and fungi (Ustilaginomycotina) in plankton. The specificity of the communities was supported by LEfSe analysis, which revealed enriched or differentially abundant protist taxa in each type of biotope. The predominance of Choanoflagellatea in the communities of cave mats and pool fingers, as well as the predominance of Synchromophyceae in the cave mats, appears to be a unique feature of Shulgan-Tash Cave. The cold-tolerant yeast Malassezia recorded in other caves was present in both plankton and biofilm communities, suggesting its resilience to low temperatures. However, no potentially harmful fungi were detected, positioning this research as a baseline for future monitoring. Our results emphasize the need for ongoing surveillance and conservation efforts to protect the fragile ecosystems of Shulgan-Tash Cave from human-induced disturbances and microbial invasions. [ABSTRACT FROM AUTHOR]

The fouling behavior of whey protein concentrate (WPC) in food‐grade polyether ether ketone (PEEK) heat exchangers was compared to benchmark stainless steel (SS) to evaluate if fouling can be better mitigated by using PEEK. No research has been conducted on WPC fouling behavior of PEEK at WPC concentrations of 2–6 g/L and heat flux densities of 45–55 kW/m2. It was found that PEEK materials led to a reduction in heat resistance of up to 40%. At WPC concentrations of 6 g/L, a fouling factor of 0.9 m2 K/kW was measured for PEEK compared to 1.6 m2 K/kW for SS. Despite a constant heat flux, fouling curves for PEEK showed an asymptotic behavior, whereas linear fouling was observed for SS. To achieve a comparable heat resistance between PEEK and SS heat exchangers, the operating time could be extended by 9 h when using PEEK materials. Investigations of the deposit mass showed that even though the heat transfer resistance is limited on PEEK, fouling continued to grow at a decreased rate. It was found that the fluid started to evaporate underneath the fouling layer, which led to a partial detachment of the fouling layer and therefore mitigated the heat resistance effects of fouling. To test whether these results are transferable to larger setups, experiments on a scale‐up apparatus were conducted. A very similar behavior was qualitatively observed; however, measured deposition deviated on average by 18%. PEEK surfaces also showed great promise regarding cleanability, with fouling layers detaching completely after drying for 10 min and restarting the process. This restored the heat transfer coefficient to its clean state. A cleaning in place therefore seems feasible. In contrast, fouling layers on SS did not detach through drying and had to be chemically cleaned to restore its heat transfer capacity. [ABSTRACT FROM AUTHOR]

This experimental study explores the mitigation of membrane fouling in membrane bioreactors (MBRs) through the combined use of granular activated carbon (GAC) and powdered activated carbon (PAC). The research assesses the impact of these materials on the fouling resistance, critical flux, and permeate quality using various mixed liquor suspended solids concentrations and carbon dosages. The results indicate that the GAC-PAC combination significantly reduces the total filtration resistance, particularly the cake layer resistance, by 11.7% to 13.6% compared to setups without activated carbon or with the individual carbon types. The study also reveals that this combination decreased the fouling rate by 15% to 24% at critical flux steps, demonstrating substantial improvements in fouling mitigation and operational efficiency. Furthermore, the GAC-PAC combination, which produces an adsorption process, enhances the permeate quality, achieving the near-complete removal of organic matter, total nitrogen, and turbidity, with total phosphorus removal reaching 99%. These findings demonstrate that the combined use of GAC and PAC not only reduces membrane fouling but also improves the overall MBR performance, making it a viable strategy for enhancing the efficiency of wastewater treatment processes. [ABSTRACT FROM AUTHOR]

The hollow fiber filter is the primary cell‐retention device used in high‐density perfusion cell culture and often used in an alternating tangential flow (ATF) configuration. The limited commercially available diaphragm pumps for ATF prevent utilization of vertical space when scaling beyond 500 L. Stacking hollow fiber filters coupled with viscous cell culture imposes vacuum pressure exceeding facility capabilities. Additionally, the longer filter assembly increases the hold‐up volume and exceeds the diaphragm pump's fluid exchange capacity. The conventional tangential flow filtration (TFF) configuration circumvents this issue by exchanging culture from the bioreactor and cell‐retention device in a unidirectional recirculation loop; however, the increased filter length when scaled up exacerbates the TFF's inherent issue with product retention from Starling flow. Stacking commercially available 20 cm TFF filters to make up the similar single‐module length TFF used for the platform 3 and 50 L perfusion process at 41.5 and 65 cm, respectively, attempts to reduce fouling caused by Starling flow. The permeate of a single‐module filter is partitioned into short independent segments through serially stacked filters, each harvested separately. By partitioning the permeate, the sieving coefficient increased for both 3 and 50 L scales. Reduction of Starling flow was confirmed with lower total hydraulic membrane resistance throughout the culture. This work demonstrates a method for increasing sieving coefficient and filter capacity by stacking TFF filters with independent permeate streams. [ABSTRACT FROM AUTHOR]

Advances in upstream production of biologics–particularly intensified fed‐batch processes beyond 10% cell solids–have severely strained harvest operations, especially depth filtration. Bioreactors containing high amounts of cell debris (more than 40% particles <10 µm in diameter) are increasingly common and drive the need for more robust depth filtration processes, while accelerated timelines emphasize the need for predictive tools to accelerate development. Both needs are constrained by the current limited mechanistic understanding of the harvest filter‐feedstream system. Historically, process development relied on screening scale‐down depth filter devices and conditions to define throughput before fouling, indicated by increasing differential pressure and/or particle breakthrough (measured via turbidity). This approach is straightforward, but resource‐intensive, and its results are inherently limited by the variability of the feedstream. Semi‐empirical models have been developed from first principles to describe various mechanisms of filter fouling, that is, pore constriction, pore blocking, and/or surface deposit. Fitting these models to experimental data can assist in identifying the dominant fouling mechanism. Still, this approach sees limited application to guide process development, as it is descriptive, not predictive. To address this gap, we developed a hybrid modeling approach. Leveraging historical bench scale filtration process data, we built a partial least squares regression model to predict particle breakthrough from filter and feedstream attributes, and leveraged the model to demonstrate prediction of filter performance a priori. The fouling models are used to interpret and provide physical meaning to these computational models. This hybrid approach–combining the mechanistic insights of fouling models and the predictive capability of computational models–was used to establish a robust platform strategy for depth filtration of Chinese hamster ovary cell cultures. As new data continues to teach the computational models, in silico tools will become an essential part of harvest process development by enabling prospective experimental design, reducing total experimental load, and accelerating development under strict timelines. [ABSTRACT FROM AUTHOR]

The extended immersion of ships in seawater frequently results in biofouling, a condition characterized by the accumulation of marine organisms such as barnacles and algae. To combat this issue, the application of anti-fouling coatings to the hull surfaces of vessels has emerged as one of the most effective strategies. In response to the increasing global emphasis on environmental sustainability, there is a growing demand for anti-fouling coatings that not only demonstrate superior anti-fouling efficacy but also adhere to stringent environmental standards. The traditional use of organotin-based self-polishing anti-fouling coatings, known for their high toxicity, has been prohibited due to environmental concerns. Consequently, there is a progressive shift toward the development and application of environmentally friendly anti-fouling coatings. This paper reviews the toxicity and application limitations associated with conventional anti-fouling coatings. It provides a comprehensive overview of recent advancements in the field, including the development of novel self-polishing anti-fouling coatings, low surface energy coatings, biomimetic coatings, and nanostructured coatings, each leveraging distinct anti-fouling mechanisms. The paper evaluates the composition and performance of these emerging coatings and identifies key technical challenges that remain unresolved. It also proposes a multi-faceted approach to addressing these challenges, suggesting potential solutions for enhancing the effectiveness and environmental compatibility of anti-fouling technologies. The paper forecasts future research directions and development trajectories for marine anti-fouling coatings, emphasizing the need for continued innovation to achieve both environmental sustainability and superior anti-fouling performance. [ABSTRACT FROM AUTHOR]

Moisture from ar is often responsible for biofouling and corrosion on the inner walls of the air filtration system and there by affecting the bacteria colony forming units (CFU Count). This phenomenon is more prevalent in humid environment. Applying electroless Nickel-Copper-Phosphorous (Ni-Cu-P) coating on mild steel helps to prevent bio fouling. An air filtration unit with inner walls coated with nano-TiO2 and inlet filter mesh made of Luffa and coated activated charcoal and zeolite is used in the experimentation process. The inner chamber is also radiated by band C of Ultraviolet sources (UVC) with 254 nm wavelength. A sudden spike in bacteria colony count has been observed as the air filtration unit remains in off mode for prolonged duration of time. The efficacy of the air filtration unit upon remaining in off- mode for a long time has been determined in the present work considering the bacterial colony count as response. Electroless Ni-Cu-P coating has been applied at selected locations previously affected by biofouling. A predictive model has been developed following response surface methodology using bacterial colony count as response and the composition of the electroless coating bath as the process parameters. Genetic algorithm was applied for the determination of the best possible constitution of chemical coating bath for the minimization of the bacterial colony count. Bacteria Colony formation was significantly affected by the sources of Nickel ion, Copper ion and the concentration of reducing agent in the electroless Ni-Cu-P coating bath. The confirmation run showed that the observed CFU count at the optimum condition converges with the data obtained from Genetic Algorithm. [ABSTRACT FROM AUTHOR]

Abstract This research explores the enhancement of polyethersulfone (PES) membranes through the incorporation of chitosan derived from the lignicolous fungus Ganoderma sp. Utilizing wet phase inversion and solution casting techniques, chitosan was successfully integrated into the PES matrix, as confirmed by Fourier Transform Infrared Spectroscopy (FT-IR), which indicated a high deacetylation degree of 75.7%. The incorporation of chitosan significantly increased the membrane hydrophilicity, as evidenced by a reduction in the water contact angle and a substantial improvement in pure water permeability, from 17.9 L m-2 h-1 bar-1 to 27.3 L m-2 h-1 bar-1. The membrane anti-fouling properties were also notably enhanced, with the Flux Recovery Ratio (FRR) increasing from approximately 60–80%. Moreover, the chitosan-modified PES/CS membrane, particularly at a 5% chitosan concentration, demonstrated exceptional efficacy in pollutant removal, achieving over 90% elimination of total suspended solids, cadmium (Cd), and lead (Pb), alongside a 79% reduction in color during the treatment of textile wastewater.

Abstract Of the processes that are approved to produce synthetic kerosene for use in jet fuel, about half produce olefinic kerosene that is hydrotreated. The alkene concentration in synthetic kerosene is indirectly regulated through the thermal oxidative stability specification. Perceptions about the deleterious influence of alkenes on thermal oxidative stability suggest that olefinic kerosene must be deeply hydrogenated. The extent of olefin saturation required has economic implications. To evaluate what an acceptable alkene concentration in synthetic kerosene is, the impact of alkene concentration on the outcome of the jet fuel thermal oxidative stability test (JFTOT) performed at 325°C in accordance with the ASTM D3241 standard test method was experimentally evaluated. Model synthetic kerosene mixtures to which different concentrations of alkenes (1‐decene, α‐methylstyrene, indene) were added, as well as control samples were studied. In the concentration range investigated, up to 10 wt% 1‐decene, 5 wt% α‐methylstyrene, and 2 wt% indene did not lead to increased fouling in the JFTOT. Fouling passed through a minimum value with increasing alkene concentration and alkene concentration on its own was a poor predictor of thermal oxidative stability. Analysis of the kerosene collected after passing through the JFTOT found measurable changes in density and refractive index. Dissolved oxygen reacting during thermal oxidative stability testing was accounted for mostly in oxygen‐containing products in the kerosene boiling range, which indicated that the heavier products were mainly hydrocarbon in nature. In addition to initiation by autoxidation, the investigation also pointed to the existence of a second thermally initiated fouling pathway that does not require the presence of oxygen.

The nanofiltration (NF) membrane technology implemented in the recirculating aquaculture system (RAS) suffers from fouling issues, which cause a decrease in the flux value and performance of the NF membrane. Fouling can be reduced by incorporating pre-treatment units such as the multimedia filter unit (MMF) and activated carbon filter (CF). Therefore, this research aims to minimize fouling and maintain optimal membrane flux and performance by integrating pre-treatment units such as MMF and CF, as well as conducting detailed flux modeling. The models simulate transport phenomena within the NF membrane system, emphasizing the impact of concentration polarization and fouling on flux and overall performance across various pre-treatment configurations under non-steady state conditions. Configuration of MMF-CF-NF demonstrated the highest overall efficiency in reducing ammonia concentration by 97.5%, nitrite by 100%, and 100% by TSS. Furthermore, the values of the solvent transport coefficient (Aw), the solute transport coefficient (Bs), and the contaminant accumulation volume (X) varied for each configuration due to different treatments, leading to varying membrane workloads. Validation and statistical analysis of the permeate concentration model demonstrated that the developed model has a strong capability to accurately describe and predict the filtration process using the NF membrane, with solute transport coefficient contributing most significantly to influencing the concentration permeate NF. [ABSTRACT FROM AUTHOR]