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This study investigated the potential impact of salinity levels on the treatment performance and membrane fouling of MBR seeded with sludge from saline industrial effluent treatment plants. A pilot-scale MBR received mixed saline industrial effluents at an organic loading rate (OLR) of 1.3 g COD/L·d and a feed-to-micro-organism (F/M) ratio of 0.33 g COD/g TSS. The effects of the variable salt concentrations of 5, 10, 20, and 25 g/L were investigated. The ranges of ammonia and total nitrogen (TN) concentrations were 22.2–26.3 mgN/L and 55.1–59.2 mgN/L, respectively. The MBR achieved promising results for chemical oxygen demand (COD) and biochemical oxygen demand (BOD), with removal ranges of 95.4–97.2% and 98.3–98.8%, respectively. The system provides 93.2–96.7% and 81.6–92.5% for ammonia and TN removal. Up to a 20 g/L salinity level, there were no significant effects on treatment performance, but 25 g/L significantly declined daily and specific COD removal load. Despite this, residual values at 25 g/L were better and met the Saudi standard for effluent discharge. This is due to membrane fouling which declined the flux rate with a spontaneous reduction of OLR and F/M ratio. The MBR system inoculated with high-salinity-adapted sludge could be managed to release treated effluent that meets Saudi disposal limits by modifying the F/M ratio via reducing the flux or increasing the mixed liquor suspended solid (MLSS) concentration. [ABSTRACT FROM AUTHOR]

This study evaluates the influence of micropollutant chemical characteristics on the removal of pharmaceutical substances through three different treatments: membrane bioreactor, full wastewater treatment with final filtration (WWTP), and secondary treatment through a conventional activated sludges system, operated in parallel at realistic sludge retention time (SRT) over three years and four sampling campaigns. Treated wastewater from the WWTP enters the local canal with a low dilution ratio. Therefore, the monitoring of water contamination is of particular interest for a reliable assessment of environmental risk. A total of 39 pharmaceutical substances were screened. While differences among the three types of treatments were found statistically not significant, data analysis performed through a generalized linear model showed that both the influent concentration and the physicochemical characteristics are strong predictors for the removal of micropollutant. SRT had no significance for the three types of treatment of this study. Finally, pharmaceuticals were divided into three major classes based on their influent concentration and removal. A canonical discriminant analysis was used to predict the removals and showed that the pharmaceuticals removal rates are strongly influenced by their hydrophobicity/hydrophilicity and enabled to predict their removal categories with high accuracy (i.e., 65% of correct predictions). [ABSTRACT FROM AUTHOR]

Uncertainty of data, the degree to which data are inaccurate, imprecise, untrusted, and undetermined, is inherent in many contemporary database applications, and numerous research endeavours have been devoted to efficiently answer skyline queries over uncertain data. The literature discussed two different methods that could be used to handle the data uncertainty in which objects having continuous range values. The first method employs a probability-based approach, while the second assumes that the uncertain values are represented by their median values. Nevertheless, neither of these methods seem to be suitable for the modern high-dimensional uncertain databases due to the following reasons. The first method requires an intensive probability calculations while the second is impractical. Therefore, this work introduces an index, non-probability framework named Constrained Skyline Query processing on Uncertain Data (CSQUiD) aiming at reducing the computational time in processing constrained skyline queries over uncertain high-dimensional data. Given a collection of objects with uncertain data, the CSQUiD framework constructs the minimum bounding rectangles (MBRs) by employing the X-tree indexing structure. Instead of scanning the whole collection of objects, only objects within the dominant MBRs are analyzed in determining the final skylines. In addition, CSQUiD makes use of the Fuzzification approach where the exact value of each continuous range value of those dominant MBRs' objects is identified. The proposed CSQUiD framework is validated using real and synthetic data sets through extensive experimentations. Based on the performance analysis conducted, by varying the sizes of the constrained query, the CSQUiD framework outperformed the most recent methods (CIS algorithm and SkyQUD-T framework) with an average improvement of 44.07% and 57.15% with regards to the number of pairwise comparisons, while the average improvement of CPU processing time over CIS and SkyQUD-T stood at 27.17% and 18.62%, respectively. [ABSTRACT FROM AUTHOR]

Anaerobic membrane bioreactors (AnMBRs) have emerged as an effective technology for treating domestic and industrial wastewater. However, AnMBRs typically exhibit low membrane fluxes (<10 L/m2.h), which limits their wide application. Despite the use of various techniques to control membrane fouling, the relationships among these techniques and the challenges associated with their application remain unclear. Current literature categorizes membrane fouling control approaches into four classes, namely a reduction in the concentration of soluble microbial products (SMP), an increase in shear, an increase in particle size, and membrane optimization. Biological techniques are effective in reducing the concentration of SMP but limit the flexibility of reactor operation. The remaining three methods are non-biological techniques. Shear-induced lift force, permeation drag force, and the xDLVO theory on microparticles can be used to elucidate the mechanisms of these non-biological techniques, except for dynamic membranes. This indicates that other proposed additional forces may be disregarded. Non-biological techniques are associated with high energy costs and membrane damage. Hydrophilic membranes are effective but super-hydrophilic membranes have not been used in AnMBRs. Different materials rather than the membrane should be applied to create an electronic field for membrane fouling control. The application of dynamic membrane should not result in biofouling of a downstream water treatment process. Among current techniques, dosing flocculant is the most promising method for controlling membrane fouling, but developing an auto-flocculant dosing strategy is vital. Overall, this article provides an overview of current membrane fouling strategies and reveals their inherent relationships and challenges for their applications. [ABSTRACT FROM AUTHOR]

Introducción: El monitoreo biológico en los sistemas de tratamiento de aguas residuales por lodos activados ofrece resultados integrales y es una herramienta complementaria en las decisiones de control operacional. Una herramienta para ello es el Índice Biológico de Lodos (IBL), basado en protozoos, pero en Costa Rica hay pocos datos sobre este tema. Objetivo: Evaluar el IBL como herramienta de bioindicación en agua residual hospitalaria. Métodos: De febrero a abril de 2022 tomamos, en un hospital costarricense, un total 36 muestras de un sistema de tratamiento por lodos activados Convencional y de un Biorreactor de Membrana (MBR). Resultados: La eficiencia de remoción del DBO y DQO fue mayor en el MBR, sin embargo, en ambos casos la eficiencia fue alta (mayor al 85%), y esto se relaciona con los altos valores de IBL. La eficiencia de remoción nitrógeno no superó el 50% (MBR). Ningún parámetro ambiental tuvo correlación con los valores de IBL, pero la edad del lodo afectó el valor de IBL. Conclusión: Tanto en el sistema de tratamiento convencional como en el MBR, los valores promedio de IBL demuestran un buen desempeño y una alta calidad de los lodos activados.

Uncertainty of data, the degree to which data are inaccurate, imprecise, untrusted, and undetermined, is inherent in many contemporary database applications, and numerous research endeavours have been devoted to efficiently answer skyline queries over uncertain data. The literature discussed two different methods that could be used to handle the data uncertainty in which objects having continuous range values. The first method employs a probability-based approach, while the second assumes that the uncertain values are represented by their median values. Nevertheless, neither of these methods seem to be suitable for the modern high-dimensional uncertain databases due to the following reasons. The first method requires an intensive probability calculations while the second is impractical. Therefore, this work introduces an index, non-probability framework named Constrained Skyline Query processing on Uncertain Data (CSQUiD) aiming at reducing the computational time in processing constrained skyline queries over uncertain high-dimensional data. Given a collection of objects with uncertain data, the CSQUiD framework constructs the minimum bounding rectangles (MBRs) by employing the X-tree indexing structure. Instead of scanning the whole collection of objects, only objects within the dominant MBRs are analyzed in determining the final skylines. In addition, CSQUiD makes use of the Fuzzification approach where the exact value of each continuous range value of those dominant MBRs’ objects is identified. The proposed CSQUiD framework is validated using real and synthetic data sets through extensive experimentations. Based on the performance analysis conducted, by varying the sizes of the constrained query, the CSQUiD framework outperformed the most recent methods (CIS algorithm and SkyQUD-T framework) with an average improvement of 44.07% and 57.15% with regards to the number of pairwise comparisons, while the average improvement of CPU processing time over CIS and SkyQUD-T stood at 27.17% and 18.62%, respectively.

Retinitis pigmentosa (RP) ranks first in the structure of hereditary retinal diseases. Vasoconstriction is one of the main ophthalmoscopic indications of PR. Laser speckle flowgraphy (LSFG) is a new non-invasive method that allows quantitative assessment of blood flow in the posterior pole of the eye.Purpose: to evaluate changes in blood flow as determined by the LSFG method in the area of the optic nerve head (ONH) and the macular area in PR patients.Material and methods. The study included 16 patients with PR aged 25 to 70 years. The control group consisted of 40 healthy volunteers, comparable in gender and age. Blood flow was determined using an LSFG-RetFlow device (Nidek), the main indicator of blood flow determined was MBR (Mean Blur Rate), which was measured for the entire study area, as well as separately for large vessels, and for the microvasculature. A wide range of pulse wave parameters determined by the tool instrument was also analyzed.Results. This study revealed a significant decrease in blood flow in PR patients compared with healthy individuals in different age groups and at different stages of the disease (p d 0.05). In patients with low visual acuity, the deficit of blood flow in the macular area was found to be more pronounced.Conclusion. LSFG is an effective method for determining ocular blood flow in PR patients. The data may indicate that a decrease in blood flow is an independent pathogenetic factor in the development of PD. In the future, the method can be used to assess the effectiveness of therapy of patients with PR.

The effects of pore size and surface modification on the fouling and cleaning properties in membrane bioreactor (MBR) with backwashing were studied using porous alumina microfiltration membranes with pore sizes of 0.2, 0.5, 0.7, and 1.5 μm. The surface modifications were conducted using silane coupling agents, 3-Aminopropyltrimethoxysilane (APTMS) for a positively charged surface, Chlorotrimethylsilane (TMS) for a weak hydrophobic surface, and Trichlorooctadecylsilane (ODS) for the strong hydrophobic surface. The two-stage fouling behaviors were typically observed and elucidated by shifting the fouling mechanism from adsorption to cake formation during operation. The fouling properties were characterized by the filtration resistance of cake layer Rc, the filtration resistance caused by adsorption Ra, which were determined from the difference in the filtration resistance for the filtration direction and the backwash direction, and Transition Point (TP) which divides the fouling stages. From the effect of pore size, the membrane having 0.2 μm, which was the smallest pore size in this study, showed the highest anti-fouling performance. This result was elucidated by pore blocking caused by particulate foulants having particle sizes close to the membrane pore size. The effect of the surface modification was mainly found in the adsorption properties of foulants. The TMS-modified membrane, which had a weak hydrophobic pore surface, showed the highest anti-fouling performance, which would be provided by blocking the further accumulation of foulants by the adsorption layer formed in the initial stage of the operation. From the cleaning properties of the fouled membranes by physical and chemical cleanings, the unmodified membrane, which has a hydrophilic surface, showed the best cleaning properties. The decrease in the absolute value of the zeta potential due to fouling was observed as a general trend and the adsorption of foulants in MBR was one of the causes of the decrease.

In recent years, ceramic membranes have been increasingly used in membrane bioreactors (MBRs). However, membrane fouling was still the core issue restricting the large‐scale engineering application of ceramic MBRs. As a novel and alternative technology, ultrasonic could be used to control membrane fouling. This research focused on the efficiency and mechanism of ultrasonic controlling membrane fouling in ceramic MBRs. The results showed that ultrasonic reduced the sludge concentration in MBR, and the average particle size of sludge was always in a high range. The sludge activity of the system was stable at 6–9 (mg O2·(g MLSS·h)−1), indicating that ultrasonic did not destroy the activity of microorganisms in the system. The extracellular polymer substance (EPS) of the ultrasonic group was slightly higher than that of the control group, while the soluble microbial product (SMP) content was relatively stable. The ceramic membrane of the ultrasonic group has a partial retention effect on the organic components. The application of ultrasonic slowed down the decrease of the hydrophilicity of the ceramic membrane. The main pollutants on the membrane surface exist in the form of aromatic and heteroaromatic rings, alkynes, and so forth. Ultrasonic removes the amide substances from the membrane surface. Membrane fouling resistance is mainly due to membrane pore blockage, accounting for 75.53%. Practitioner Points: Enrich the research on the mechanism of ultrasonic technology in membrane fouling control.The MBR can still operate normally with ultrasonic applied.The time for the ceramic membrane to reach the fouling end point is 2.4 times that without ultrasonic.The main cause of membrane fouling was pore blocking, accounting for 75.53%. [ABSTRACT FROM AUTHOR]

This paper advocates for a proactive approach to traffic safety by introducing a collaborative Misbehaviour Response System (MBR) designed to preemptively address hazardous driving behaviours such as wrong-way driving and distracted driving. The system integrates with electric vehicles (EVs), leveraging advanced technologies like ADAS, edge computing, and cloud services to enhance road safety. Upon detection of misbehaviour, the MBR system utilizes data from interconnected parking facilities to identify the nearest safe location and provides navigation guidance to authorities and nearby vehicles. The paper presents a prototype of the MBR system, demonstrating its efficiency in detecting misbehaviours and coordinating swift responses. It also discusses the system's limitations and societal implications, outlining future research directions, including integration with autonomous vehicle systems and variable speed limit technologies, to further improve road safety through proactive and context-aware response mechanisms. [ABSTRACT FROM AUTHOR]

Forward osmosis (FO) technology, though gaining interest in the last two decades, is still regarded as non-economically viable option. In the light of the recent advances in FO membrane technology and potential benefits of its integration with reverse osmosis (RO) for desalination, wastewater treatment and energy recovery, a comprehensive analysis for FO-RO integration was carried out. This integration considers a layout which concentrates FO feed (wastewater) and dilutes the draw solution, producing potable water via RO and methane from the concentrate through upflow anaerobic sludge blanket in a separate energy recovery unit. Compared to mainstream technologies exemplified by the seawater reverse osmosis (SWRO), membrane bioreactor followed by reverse osmosis (MBR-RO), and Hitachi’s REMIX water system, this study reveals that FO-RO integration for both potable water production and energy recovery has become economically viable with a 9% life cost advantage over MBR-RO and a 20% advantage over SWRO and conventional activated sludge process combined. Moreover, the FO-RO integration showed a cost benefit ratio of 1.17, reflecting its economic viability. With ongoing advancements in FO technology and energy recovery and the many overlooked advantages it offers, this integration has the potential to become the new norm for desalination and wastewater treatment.

This study investigated the potential impact of salinity levels on the treatment performance and membrane fouling of MBR seeded with sludge from saline industrial effluent treatment plants. A pilot-scale MBR received mixed saline industrial effluents at an organic loading rate (OLR) of 1.3 g COD/L·d and a feed-to-micro-organism (F/M) ratio of 0.33 g COD/g TSS. The effects of the variable salt concentrations of 5, 10, 20, and 25 g/L were investigated. The ranges of ammonia and total nitrogen (TN) concentrations were 22.2–26.3 mgN/L and 55.1–59.2 mgN/L, respectively. The MBR achieved promising results for chemical oxygen demand (COD) and biochemical oxygen demand (BOD), with removal ranges of 95.4–97.2% and 98.3–98.8%, respectively. The system provides 93.2–96.7% and 81.6–92.5% for ammonia and TN removal. Up to a 20 g/L salinity level, there were no significant effects on treatment performance, but 25 g/L significantly declined daily and specific COD removal load. Despite this, residual values at 25 g/L were better and met the Saudi standard for effluent discharge. This is due to membrane fouling which declined the flux rate with a spontaneous reduction of OLR and F/M ratio. The MBR system inoculated with high-salinity-adapted sludge could be managed to release treated effluent that meets Saudi disposal limits by modifying the F/M ratio via reducing the flux or increasing the mixed liquor suspended solid (MLSS) concentration.

This study focuses on assessing the sewage characteristics and performing of the Hospital Wastewater Treatment Plant (WWTP) for Al-Mauaney Hospital in Basrah Governorate .samples was taken from WWTS waste and tested for pollutants using (APHA) procedures and compared to standard criteria. COD, BOD, temperature, E.C., TSS, and TDS were all tested in the laboratory. DO, NH3, and NO3 were chosen as effluent quality indicators. Identical to the standard limits in Iraqi Standard Specification, despite some of them experiencing a minor modification during the treatment stages. But for COD and BOD, which exceeded the permissible limit despite the high removal efficiency, because the values at the entrance were high because they came from hospital waste, where the values at the influent were for COD 665.4 mg/l &504.6 mg/l, while the BOD values were 283.6 mg/l &171.2 mg/l in summer and winter, respectively, while the effluent values were 129.7&102.8 for COD and 73.4&53.8 for BOD. As well as for the NO3-N results for the effluent, which was unstable inflow and effluent, but in no way did it exceed the Iraqi effluent which was 50 mg/l.

Disorders of ocular perfusion are associated with huge amout of diseases, including such socially significant as diabetic retinopathy and glaucoma. To date, there is no gold standard for measuring ocular perfusion. An innovative method for two-dimensional assessment of eye blood flow — laser speckle flowgraphy (LSFG) — has been developed recent years and implemented in ophthalmological practice.Purpose: to evaluate the possibilities of LSFG for determining ocular blood flow and to find out the age dependence of the obtained indicators of ocular blood flow.Materials and methods. The study includes 60 healthy volunteers. The examined persons were divided into 3 groups of 20 people depending on their age — 20–40 years old, 41–60 years old, and over 61 years old. All examined persons had high visual acuity and normal blood pressure. The study was carried out on an LSFG-RetFlow device (Nidek). The shape of the pulse wave, its qualitative and quantitative characteristics including the main parameter of LSFG - MBR (Mean Blur Rate) were determined.Results. A significant decrease with age of most studied parameters of blood flow volume was revealed, the changes were significant (p £ 0.05). The highest MBR parameters were noted in the group of 20–40 years old. In the macular area, MBR values decreased more significantly in the group after 60 years age, while for the optic nerve head (ONH), a decrease has been already noted after 40 years age. In average, the decrease was 25–34 % for the ONH area and 33–38 % for the macular area. Changes of the other parameters of the pulse waveform had a similar trend.Conclusion. LSFG is a reliable method for quantifying ocular blood flow. Our data support that LSFG-derived MBR and pulse wave measurements may be useful biomarkers for ocular perfusion changes. The identified age-related blood flow changes should be taken into account during the analysis of patients data.

This study focuses on assessing the sewage characteristics and performance of the Hospital Wastewater Treatment Plant for AL-Mauany hospital in Basrah Governorate. Samples were taken from wastewater treatment plants (WWTP) waste and tested for pollutants using (APHA) procedures and compared to standard criteria. COD, BOD, temperature, EC, TSS, and TDS were all tested in the laboratory. DO, NH3, and NO3 were chosen as effluent quality indicators. Identical to the standard limits in Iraqi Standard Specification, despite some of them experiencing a minor modification during the treatment stages. But for COD and BOD, which exceeded the permissible limit despite the high removal efficiency, because the values at the entrance were high because they came from hospital waste, where the values at the influent were for COD 665.4 mg/l and 504.6 mg/l, while the BOD values were 283.6 mg/l and 171.2 mg/l in summer and winter, respectively, while the effluent values were 129.7 and 102.8 for COD and 73.4 and 53.8 for BOD. As well as for the NO3-N results for the effluent, which was unstable inflow and effluent, but in no way did it exceed the Iraqi effluent which was 50 mg/l. [ABSTRACT FROM AUTHOR]

Fouling is one of the most challenging issues faced by membrane technology. One possible approach to address membrane fouling is incorporating hydrophilic materials into the membrane matrix. Graphene oxide (GO) can be a potential candidate due to its hydrophilicity, if its cost could be significantly reduced. In this study, a GO‐polysulfone (PSF) composite membrane is fabricated with a thin GO‐PSF active layer and a PSF substrate. The obtained membrane shows good anti‐fouling property in real sewage system, compared with the pristine PSF membrane, and the flux recovery ratio is enhanced by 20%–30%. In addition, the antibacterial property of GO‐PSF membrane to Escherichia coli is enhanced. The work provides a guidance to improve the performance membranes and reduce the cost. [ABSTRACT FROM AUTHOR]

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This paper describes a case study involving a revamping of a full-scale membrane bioreactor that treats landfill leachate and other liquid wastes. The main change was the introduction of nitritation/denitritation in alternating cycles instead of the classic denitrification/nitrification process, together with the installation of fine bubble diffusers, a reduction in the volume of the biological compartment, and an increase in the equalization volume. The most significant results were obtained for the biological compartment, with a decrease in the specific energy consumption of 46.6%. At the same time, the removal efficiency of COD, BOD, and TN substantially remained the same before and after plant revamping, while the removal efficiency of TP increased over the years, reaching an average value of almost 71%. Regarding the ultrafiltration unit, the specific flux (or permeability) was characterized by an increasing trend. At the same time, the specific energy consumption of this section decreased by 9.4%. These results led to the conclusion that the changes introduced with the revamp led to a more stable process, a reduction in membrane fouling, and important energy savings.

This paper advocates for a proactive approach to traffic safety by introducing a collaborative Misbehaviour Response System (MBR) designed to preemptively address hazardous driving behaviours such as wrong-way driving and distracted driving. The system integrates with electric vehicles (EVs), leveraging advanced technologies like ADAS, edge computing, and cloud services to enhance road safety. Upon detection of misbehaviour, the MBR system utilizes data from interconnected parking facilities to identify the nearest safe location and provides navigation guidance to authorities and nearby vehicles. The paper presents a prototype of the MBR system, demonstrating its efficiency in detecting misbehaviours and coordinating swift responses. It also discusses the system’s limitations and societal implications, outlining future research directions, including integration with autonomous vehicle systems and variable speed limit technologies, to further improve road safety through proactive and context-aware response mechanisms.

Bulking and foaming are extreme filamentous bacterial growths that present serious challenges for the biological leachate treatment process. The current study evaluates the performance of long-term full-scale membrane bioreactor (MBR) treating landfill leachate, specifically focusing on filamentous bacteria overgrowth in the bioreactors. The influence of the variation in leachate structure and operational conditions on floc morphology and filamentous bacteria overgrowth were analyzed for 11 months of operation of the full-scale MBR system. The average chemical oxygen demand (COD) and NH4-N removal efficiencies of the system were 87.8 ± 4% and 99.5 ± 0.7%. However, incomplete denitrification was observed when the F/M ratio was low. The high C/N ratio was observed to enhance the frequency of small flocs. Furthermore, a poor to medium diversity of the microbial community was observed. Haliscomenobacter hydrossis, Microthrix parvicella, and Type 021N were found as the most numerous filamentous organisms. Paramecium spp., Euplotes spp., and Aspidisca spp. were found in small quantities. The limited concentration of PO4-P in the leachate compared to high COD and NH4-N concentrations most probably caused phosphate deprivation and increased abundance of identified filamentous microorganisms. This work is the first study in Türkiye that investigates the bulking and foaming problem in full-scale MBR that treats landfill leachate. Hence, it may provide some pioneering perspectives into landfill leachate remediation by monitoring the hybrid biological system. [ABSTRACT FROM AUTHOR]

In this study, flat sheet submerged MBR (FS‐SMBR) was investigated under 6 and 4 h hydraulic retention times (HRT) and 40 days solid retention time with real municipal wastewater. The implementation of the treatment system was evaluated in terms of physico‐chemical and microbial analysis as well as sludge characterization. The permeate of FS‐SMBR complied with the standards for reuse and non‐detectable levels of faecal coliform was achieved at 6 and 4 h HRTs, with pore‐blocking resistances (Rt) of 28 × 1011 and 40 × 1011/m, respectively. Examining another dominant factor, that is, sludge viscosity, the best results were acquired using HRT 4 h for domestic wastewater. Furthermore, the results obtained were validated and calibrated using the GPS‐X software simulator, and the results of modelled data were completely matched with the experimental data under the same conditions. [ABSTRACT FROM AUTHOR]

Municipal wastewater treatment saves fresh water resources from contamination and provides a sustainable approach for reuse in water-stress regions. Herein, the impact of ferric chloride addition to cloth-media MBR treating municipal wastewater was tested for treatment performance, membrane filterability and sludge particle size distribution. Dosing of 7.5 and 15 mg/l of FeCl3 did not show any significant impacts on the removal of chemical oxygen demand and ammonia compared to the control test. However, the addition of ferric chloride increases percentage removal of total phosphorous from 33.5 to 39.5 and 46.5% at doses of 7.5 and 15 mgFeCl3/l, respectively. The ferric chloride addition did not enhance membrane filterability or flocculation of the sludge particles. On batch and Jar test experiments, the removal of total phosphorous reached up to 86% at dose of 120 mgFeCl3/l which shows that each mg of P needs 8 mg of Fe (22 mgFeCl3). The batch and jar test experiments did not show any significant impacts of ferric chloride up to 120 mg/l on the biological activity and particle size distribution of the sludge. To enhance phosphorus removal in the MBR systems, coagulant addition to the final permeate is recommended to avoid any negative impacts on the flux rate and to minimize coagulant addition. [ABSTRACT FROM AUTHOR]

An activated sludge system can be inoculated with enriched nitrifying bacteria to enhance NH4+-N removal, or enriched nitrifying bacteria can be added directly to a river to remove NH4+-N. However, the enrichment culture is still generally inefficient and the technical bottleneck has not been clarified. Previous studies have shown that extracellular free organic carbon (EFOC) inhibits the growth of some autotrophic bacteria, and separating EFOC during culture with a membrane bioreactor (MBR) promotes the continuous growth of autotrophic bacteria and CO2 fixation. However, whether a membrane bioreactor can also be used to enrich and culture autotrophic nitrifying bacteria by separating EFOC has not been verified. In this study, an MBR was constructed to separate EFOC during the culture of nitrifying bacteria in activated sludge to confirm that the MBR better enriches and cultures nitrifying bacteria than a sequencing batch reactor (SBR). Our results showed that after culture for 34 days, the rate of NH4+-N removal and the nitrification rate by nitrifying bacteria in the MBR were 2.20-fold and 1.42-fold higher than in the SBR, respectively. The abundance of Nitrospira in the MBR was also 7.23-fold greater than in the SBR at the end of the experimental period. After 34 days, the average concentration of EFOC and the average EFOC/bacterial organic carbon ratio in the MBR were only 53% and 37% of those in the SBR, respectively. A correlation analysis suggested that the timely removal by the MBR of the EFOC generated during the culture process may be an important factor in promoting the growth of autotrophic nitrifying bacteria. The possible mechanism by which the MBR separates EFOC to the growth of promote autotrophic nitrifying bacteria is discussed from the perspective of the inhibitory effect of EFOC on cbb gene transcription. Our experimental results suggest a new approach to enhancing the enrichment of autotrophic nitrifying bacteria and extending the application of MBRs. [ABSTRACT FROM AUTHOR]

Membrane fouling and mineral scaling remain major drawbacks for MBR technology. Membrane fouling reduces the filtration ability in MBR systems by increasing transmembrane pressure (TMP) and thus increases the operational cost. This study focused on the application of commercially available antiscalant in a pilot MBR system and the effect of diffuser perforation diameter for the treatment of high mineral scaling propensity wastewater. Submerged flat sheet membranes (Kubota, nominal pore size: 0.4 µm) were used in the pilot-scale test unit operated in the wastewater treatment plant of ITOB Organized Industrial Zone, Izmir, Turkey. The commercially available antiscalants employed were coded AS-1 and AS-2 for antiscalant study. Long term effect of the two antiscalants employed was investigated under high mixed liquor suspended solid (MLSS) concentration (17–21 g/L) for two months of MBR operation. The effect of low MLSS concentration (10–13 g/L) was also studied without changing the concentration of antiscalant type and concentration. AS-1 was found to be more effective in terms of mineral scale control. The effect of diffuser perforation diameter (1, 3 and 5 mm) on mineral scaling minimization in MBR pilot system was also studied. The best performance with respect to membrane fouling control was found with an air diffuser having 3 mm of diffuser perforated diameter. Some quality analyses of the product water were also carried out to assess the effect of antiscalant addition on microbial activities in the MBR unit. The findings in this study reveal that the use of antiscalants has not affected biological treatment performance of MBR pilot system. The removal ranges obtained during all MBR studies were 98.47–99.9%, 84.62–99.4%, 89.5–98.5%, 86.90–99.9%, 67.01–99.2%, 75.03–93.9%, and 20.36–71.5% for total suspended solid (TSS), color, chemical oxygen demand (COD), NH4-N, PO4-P, NO2-N, and total nitrogen (TN) respectively. [ABSTRACT FROM AUTHOR]

The assessment of the environmental footprint of an organization or product is based on methods published by the European Union Joint Research Centre, which take 16 impact areas into account. Among the listed categories are human and freshwater ecosystem toxicities. Standard protocols utilize just chemical parameters as input data, hindering the determination of the full impact of complex mixes, such as pollutants released into the environment. Biological assays enable us to overcome this gap: in the present work, assays were employed to determine both baseline and specific toxicity to aquatic species (green algae, luminescent bacteria, and crustacean cladocera) as well as specific toxicity (mutagenicity and carcinogenicity). Ecological footprint was estimated with regard to the impact categories "freshwater toxicity" and "human cancer toxicity" following the standard methodology. In parallel, the impact on the above categories was estimated using the results of biological assays as input. Standard and bioassay-based results are not always congruent, and conventional methods generally underestimate the effects. Likewise, the choice of reference substance (metals or organics) influences the quantification of impact. Appropriate batteries of biological assays could therefore be utilized to complement LCA (Life Cycle Assessment) techniques in order to make them more sensitive when considering toxicity in mid-term impact categories. [ABSTRACT FROM AUTHOR]

The porous medium approach has been applied by others to study the global hydrodynamics in hollow-fiber (HF) membrane bioreactors (MBR). This study explores the usability of the porous medium approach for flat-sheet (FS) MBR and introduces a CFD-based numerical calibration of the porous parameters. Two key modeling strategies are suggested to ensure the pressure prediction accuracy: (1) use SST turbulence model incorporated with an intermittency transition model (SSIT); (2) considerate two-phase flow during the calibration. The results showed that SSIT significantly improved the pressure prediction of the flow between two sheets. Also, unlike HF MBR, the gas phase was observed to be non-negligible during the calibration for FS MBR. The numerically calibrated porous parameters were then applied in a three-dimensional simplified model (SPM), where multiple membrane sheets were treated as one porous zone. The SPM was compared with a realistic model (RM), where all membrane sheets were simulated directly. A similar pressure distribution was observed in both models; however, local flow characteristics (i.e., the acceleration of the flow entering the module zone) were not reflected in the SPM. Hence, it is recommended to use the porous medium approach for global hydrodynamics investigation when the local flow characteristics are not of interest. HIGHLIGHTS This study introduces a CFD-based numerical calibration method of the porous parameters.; Unlike the standard calibration method of the porous parameters for HF MBR, this study suggests using two-phase (air-water) flow during the calibration, and the viscous loss term should not be omitted.; This study discusses the capabilities and limitations of the current porous medium approach.;

In order to meet the influent water quality of reverse osmosis membrane (RO) or nanofiltration membrane (NF) in the water reuse system of printing and dyeing wastewater, and to cope with the impact of actual printing and dyeing wastewater quality and water quantity, a new type was developed and submerged high-strength membrane filtration (HMF) technology for wastewater treatment compared with the traditional membrane bioreactor (MBR) technology. The combined effect of the process was investigated. The results show that compared with the traditional MBR technology, the membrane flux increased from 11~13 L/ (m2·h) to 14~16 L/ (m2·h), and the reflux rate is reduced from 250%~300% to 20%. The water quality of the HMF process is better than that of the MBR process, especially suspend solid, as low as 1 mg/L, which effectively guarantees the influent requirements of the subsequent RO/NF. The pollution level is relatively low, which is conducive to long-term stable operation. At present, the technology has been demonstrated and applied in the advanced treatment of wastewater in the printing and dyeing industry, and has a good promotion prospect.

Anaerobic ammonium oxidation (anammox) would be a feasible treatment method for thermal hydrolysis processed sidestream (THPS). Short-term study revealed that the 1/20 diluted THPS caused a 28% decrease of specific anammox activity. The MBR achieved a volumetric nitrogen loading rate of 3.64 kg/(m3·d) with undiluted regular sidestream (RS) fed, while the reactor crashed with 70% diluted THPS as feed. The ratio of produced NO3--N to consumed NH4+-N also decreased compared with RS feeding. Candidatus brocadia was the major anammox bacteria species with the average abundance of 33.3% (synthetic wastewater), 6.42% (RS) and 2.51% (THPS). The abundances of metagenome bins for dissimilatory nitrate reduction to ammonium (DNRA) increased in the system with THPS compared with RS. The reason for the inhibition of anammox by THPS could be the high content of organic carbon in THPS, which caused the over-population of heterotrophic bacteria, i.e. DNRA bacteria, leading to anammox bacteria washout.

To reduce the hazard of sulfamethoxazole (SMX) to the water ecology, the removal mechanism of SMX in wastewater was revealed. This study evaluated the PVDF/DA modified membrane in the membrane bioreactor (MBR) toward the removal and degradation of SMX as a recalcitrant micropollutant. A strategy of dopamine for surface modification of polyvinylidene fluoride (PVDF) membrane was proposed, and PVDF/DA membrane was prepared. Subsequently, PVDF/DA was run in the MBR for 60 days, and the reactor could produce good removal ability for SMX after certain acclimation. When the SMX concentration increased from 0.5 to 2 mg/L, liquid chromatography was used for analysis, and the results showed that the average removal rate was above 85%. The removal effect of COD and NH4+-N and the degree of membrane fouling were also evaluated. By measuring the extracellular polymer (EPS) content, the results showed that after 30 days of operation, the protein and polysaccharide contents in the cake layer on the surface of the PVDF membrane were 1.35 times and 1.49 times that of PVDF/DA membrane, respectively, and the PVDF/DA membrane could alleviate membrane fouling, thereby improving the service life of the membrane and reducing its operating cost. Finally, degradation by-products are evaluated to achieve deeper insight into the degradation mechanisms in the MBR process.

Membrane fouling has been a key factor limiting the applications of membrane bioreactor (MBR). In this study, a novel umbrella-shape membrane module was applied to construct two MBRs for two-stage partial nitrification-anaerobic ammonia oxidation (PN-ANAMMOX) process. After 55 days operation, the ANAMMOX process was started and the PN process was well controlled. Then, the ANAMMOX and PN process were successfully coupled to run the PN-ANAMMOX process. On 103 days, the best nitrogen removing effect was achieved with the maximum nitrogen loading rate (NLR) of 0.4 kg N·(m3·d)−1 and the corresponding maximum total nitrogen removal rate (TNRR) of 75.23%. The umbrella-shape membrane module in both reactors only needed to be cleaned once during the operation for 105 days, indicating that the membrane module had better resistance to membrane fouling. The functional bacteria were cultivated in suspension state; moreover, the cell densities of ammonia oxidizing bacteria (AOB) and ANAMMOX bacteria (AnAOB) reached 58.32 × 1012 copies/g sludge and 28.39 × 1012 copies/g sludge. Their abundances reached 73.25% and 57.80% of the total bacteria, respectively. MBR improved by umbrella-shape membrane module could realize the rapid start-up of ANAMMOX process, effective control of PN process, and stable operation of PN-ANAMMOX process. This study provided a novel approach to control membrane fouling by optimizing the membrane module shape and widened applications of MBRs in PN-ANAMMOX process. [ABSTRACT FROM AUTHOR]

This work presented an endeavour to evolve a novel membrane bioreactor that merges an electro bioreactor (EMBR) and moving biomedia (moving bed) aiming for enhancing the biological treatment and alleviating membrane fouling. Nanocomposite membranes comprise disparate contents of ZnONPs were prepared and the one with optimum performance was harnessed for the prolonged operations. Results revealed that the mean pore size, pore size distribution, roughness parameters and contact angle measurements were declined upon the addition of ZnO-NPs. In the meantime, the permeate flux was improved by 357% at 1.5 g ZnO-NPs loading weight. Combining the biological, membrane and electrochemical processes into one EMBR system has mitigated the inherent membrane fouling by 90%, whereas this percent went further and reached more than 94% with the presence of the electric field and moving bed. The EMBBR systems have showcased a worthy enhancement in their retention capacity, and were capable to achieve 88%, 90% and 95% retention against NO3, PO4-P and COD, respectively. Likewise, during the membrane long-term operation, a sustained stable permeate flux up to 51 days was witnesses while the membrane has operated for continuous 113 days prior to cleaning. [ABSTRACT FROM AUTHOR]

[Display omitted] • Iron-tannin-framework ultrafiltration membrane (ITUM) was prepared with excellent anti-fouling ability. • ITUM owned 1.8 times higher permeance (50.2 L m-2h−2 bar−1) than commercial membrane. • ITUM achieved excellent effluent COD and NH 4 +-N quality (16.69/0 mg L-1) in MBR. • DFT simulations confirmed ITUM was attractive to microbe useful to glucose reduction. A 10 L membrane bioreactor (MBR) was constructed with novel iron-tannin-framework ultrafiltration membrane (ITUM) for membrane fouling mitigation and effluent quality improvement. Compared to commercial ultrafiltration membrane (CUM) in the same MBR, ITUM exhibited hydrophilicity with a contact angle of 64.18° (71.36° for CUM), resulting the permeance of ITUM (50.2 L m-2h−2 bar−1) 1.8 times higher than CUM. During 70-day operation, ITUM was consistently run at lower transmembrane pressure. After operation, the polyethersulfone (PES) peak intensity of ITUM reduced less than 1 % (85 % for CUM), which indicated a thinner sludge layer on ITUM. Meanwhile, the average effluent chemical oxygen demand concentration for ITUM and CUM achieved 16.69 and 17.60 mg L-1 in stable phase, respectively. For NH 4 +-N, it could reach 0 and 0.04 mg L-1. 16 s RNA results showed that Saccharibacteria accounted for 1.48 % and 1.20 % on ITUM and CUM, respectively. According to first-principles density functional theory simulations, simulated adsorption energies was −1.330 eV for gram-positive bacteria (such as Saccharibacteria). It was −0.867 eV for Fe(Ⅲ) to gram-negative bacteria. It suggests that ITUM could easily attract microorganisms with the ability of polysaccharide degradation, while reducing this type of pollutants deposition on membrane. Therefore, the ITUM received a more superior effluent quality and membrane fouling resistance. [ABSTRACT FROM AUTHOR]

• Analysis of types of fouling mechanisms in PVC/GO and PVC/GO-ZnO membranes. • Analysis of membranes according to their properties over 35 days in an MBR system. • Increasing the performance efficiency of PVC/GO-ZnO membranes compared to PVC/GO membranes. • Superior antibacterial properties of PVC/GO-ZnO membranes compared to PVC/GO membranes. Membrane fouling is still one crucial impediment in the application of membrane bioreactors (MBR). Antifouling properties of GO and GO-ZnO embedded PVC membranes in MBR were investigated. ZnO nanoparticles were decorated onto GO nanosheets and then membranes were made by NIPS method. The results revealed that the contact angle decreased from 80° for pure PVC to 67° for 0.1 wt% GO-ZnO embedded membrane. Pure water flux increased from 33 L/m2h for neat membrane to 128 L/m2h for 0.075 wt% PVC/GO-ZnO membrane. The performance of membranes was evaluated during 35 days MBR filtration system using several analyses including COD, turbidity, SMP, EPS, PSD, and EEM. Results indicated that the presence of GO-ZnO nanoparticles in the membranes has a positive effect on COD and turbidity removal due to the oxygen-containing groups attracting SMP through intermolecular force interaction. In addition, the inclusion of nanoparticles in the membranes leads to a reduction in EPS concentration. Research on PVC membranes with graphene oxide and zinc oxide nanoparticles in membrane bioreactor processes is crucial for advancing water treatment technology. These nanomaterials promise enhanced membrane performance, longevity, and efficiency in treating wastewater, leading to more sustainable and effective water treatment solutions. [Display omitted] [ABSTRACT FROM AUTHOR]

Reducing energy consumption or running cost associated with the membrane bioreactor (MBR) process is a serious challenge that needs to be addressed in treating sewage. The addition of anaerobic ammonium oxidation bacteria (AnAOB) to a running MBR has the potential to lower the aeration rate, thus decreasing the running cost in treating sewage. The results obtained showed that owing to addition of AnAOB, TN and NH4+-N removal rates increased by 9.8% and 1.13%, respectively, while the aeration rate decreased by 50%. Additionally, high throughput sequencing and isotope experiments showed that both AnAOB and heterotrophic denitrification bacteria could survive simultaneously and play an important role in nitrogen removal, with AnAOB having a significantly greater contribution. It can be concluded that the addition of AnAOB reduced the running cost of MBR in treating sewage. HIGHLIGHTS TN and NH4+-N removal rates increased by 9.8% and 1.13% with AnAOB addition;; AnAOB addition resulted in a decrease in the aeration rate by 50%;; Both AnAOB and HDB play an important role in nitrogen removal;; AnAOB contributed more significantly to nitrogen removal than HDB.;

The integration of anaerobic ammonia oxidation (anammox) into the membrane bioreactor (MBR) process (AX-MBR) is proposed in this study to reduce operating costs. The temperature was not controlled during the study. Anammox, denitrification, and nitrification were studied in the AX-MBR for 210 days. The reactor was fed with mainstream sewage from Guilin City, China. The results showed that AX-MBR could run with reduced dissolved oxygen (DO) concentration, and COD, NH4+-N, and total nitrogen removal were maintained or improved. The microbial analysis results demonstrated that the added anammox sludge could survive in the AX-MBR, but the sludge microbial diversity decreased. Nitrospira, Candidatus Kuenenia, and Nitrosomonas dominated the anammox sludge. In a word, the AX-MBR developed in this study could treat mainstream sewage with the appropriate management, and the operation costs are expected to reduce by decreasing the amount of aeration. HIGHLIGHTS Anammox was integrated into the MBR process (AX-MBR) to treat sewage.; AX-MBR was operated without temperature control for 210 days.; The effect of temperature associated with seasonal changes was investigated.; Decreasing temperature adversely affected anammox activity.; Changes in the microbial community structures were observed.;

Introduction. The study focuses on the operation of a standalone membrane bioreactor applicable as an alternative to submerged membrane modules widely used as part of small capacity wastewater treatment facilities.Materials and methods. An ultra-filtration membrane was used to perform the research in a laboratory environment. The liquid, exposed to research, represented synthetic wastewater, whose composition was similar to the one of urban wastewaters, and it had varied concentrations of suspended solids (MLSS). The membrane element, produced by Raifil (Republic of Korea), that has capillary ultra-filtration membranes, was used in the experiments. The membrane pore size is 1 micron. The total membrane filter area is one square meter. This membrane module has standard characteristics (pore size, material), typical for ultra-filtration membranes; therefore, we can assume that any further results will not demonstrate any substantial discrepancies, if ultra-filtration membranes made by other manufacturers are used to conduct experiments.Results. The author describes a methodology for the optimization of pressure and MLSS values used in the process of membrane treatment. The author obtained the pressure values at which the amount of suspended solids in the filtered material shows a sharp rise, which means a slip of suspended solids into the filtrate, or a slip of contaminants. The author also identified the operating parameters that ensure maximal capacity.Conclusions. These findings help to outline a roadmap for further research into the optimization of membrane bioreactors (both standalone and submerged units) used in wastewater treatment.

The application of iron–carbon microbial cell activated sludge (ICMC-AS) was carried out in a membrane bioreactor (MBR) processor to treat wastewater from an integrated railway station. Results showed that the chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) removal efficiencies of the original MBR processor increased from 80%, 30%, and 10% to 92%, 93.5%, and 92%, respectively. Further research showed that the combined sewage treatment system also had a strong impact resistance ability. The combined sewage treatment system ran stably when the COD, TN, and TP concentrations changed greatly. The in-depth analysis of the reaction process and reaction rate of the combined sewage treatment system revealed that the combined system is dominated by COD removal with high nitrogen removal efficiency. The removal rate constants of various pollutants were in the order: KCOD (0.647 ± 0.017) > KNO3−−N (0.416 ± 0.044) > KNH4+−N (0.275 ± 0.014) > KTN (0.258 ± 0.083). Calculations of the energy saving and carbon emission reduction of the combined system showed that the system’s annual carbon emission reduction could reach more than 388,203.55 kg CO2e, which remarkably improves the carbon emission reduction effect and obtains a good green effect. The results indicate that adding ICMC-AS to the MBR processor for combined wastewater treatment can substantially improve the efficiency of wastewater treatment and obtain better energy-saving and emission-reducing effects. This combined application provides an effective way for the transformation and upgrading of small- and medium-scale water treatment systems.

An intermittent aerator was newly developed to reduce energy costs in a flat-sheet ceramic membrane bioreactor (MBR) for industrial wastewater treatment. Large air bubbles were supplied over a short time interval by the improved aerator technology at the bottom of the flat-sheet membrane. Performance tests for the intermittent aerator were carried out in a pilot system with two cassettes immersed in a membrane tank of the 1-MGD demonstration plant at Jurong Water Reclamation Plant (JWRP) in Singapore. Stable operation was achieved at an average flow of 19–22 LMH with every-2-days MC and peak flow of 27 to 33 LMH with daily MC with reduced air flow for membrane aeration. This indicates that energy costs for membrane aeration can be reduced by using the intermittent aerator. Stable MBR operation with a projected 43% reduction in the overall operating costs could be achieved with an improved aerator together with improved MC regime and membrane cassette. [ABSTRACT FROM AUTHOR]

This study investigated coliform removal from hospital wastewater in a membrane bioreactor (MBR) and disinfection using either chlorine or ozone. A laboratory-scale MBR equipped with a hollow-fiber membrane module was operated with hydraulic retention times varied at 3 and 6 hours. The disinfection of MBR effluent was carried out using either chlorine or ozone with concentrations varied between 1 and 10 mg/l and contact time varied between 1 and 30 min. During 150 days of MBR operation, organic removal efficiencies averaged 96.5% and 97.7% for BOD and 73.6% and 84.1% during its operation at an HRT of 3 and 6 hours respectively. Simultaneously, 6.7 and 6.4 log reduction of total coliforms and 6.2 and 6.1 log reduction of E. coli were achieved under these respective HRT conditions. The use of chlorine for disinfection of MBR effluent could eliminate total coliforms and E. coli completely at >6 and 3 mg/L at 30 min contact time, whereas only >3 and 1 mg/L was required for ozone at the same contact time. There was a significant improvement of disinfection efficacy of solid-free MBR effluent compared to that of activated sludge effluent. [ABSTRACT FROM AUTHOR]

Membrane bioreactor (MBR) technology has been paid extensive attention for wastewater treatment because of its advantages of high effluent quality and minimized occupation space and sludge production. However, the membrane fouling is always an inevitable problem, which causes high operation and maintenance costs and prevents the wide use of MBR technology. The membrane biofouling is the most complicated and has relatively slow progress among all types of fouling. In recent years, many membrane biofouling control methods have been developed. Different from the physical or chemical methods, the biological-based strategies are not only more effective for membrane biofouling control, but also milder and more environment-friendly and, therefore, have been increasingly employed. This paper mainly focuses on the mechanism, unique advantages and development of biological-based control strategies for MBR membrane biofouling such as quorum quenching, uncoupling, flocculants and so on. The paper summarizes the up-to-date development of membrane biofouling control strategies, emphasizes the advantages and promising potential of biological-based ones, and points out the direction for future studies. HIGHLIGHTS Membrane biofouling is the most complicated among all types of membrane fouling.; New physical and chemical methods may hurt membranes and environment.; Cheaper enzyme extraction methods for enzymatic control of membrane biofouling need to be introduced.; Environmental conditions and cost are the main limitations of biological strategies.; The effects of biological methods on the microbial ecology need to be explored.;

• Bubbles and an electric field were applied for the first time. • The two provided a synergistic effect on membrane fouling control. • Bubbles and an electric field affected micro and nano particles respectively. • The effect was significant in surface water with complex particle contents. High-level membrane fouling control is required in various membrane processes. Different techniques have been proposed for membrane fouling control, while the synergistic effects of the techniques are less explored. We proposed a novel membrane fouling control approach by applying slug flow and an electric field simultaneously. In contrast to synthetic bulk solutions, surface water containing different particles with various properties was applied. Results showed that transmembrane pressure (TMP) increased from 8 kPa to 10 kPa in 30 min at an optimized air velocity, showing a significant increasing trend. Nevertheless, by applying an electric field with a voltage ranging from 0.5 V to 1.0 V, TMP remained relatively constant over 120 min of filtration with a permeate flux at 100 L/m2.h, showing that a significant membrane fouling control effect was achieved. Particle size and zeta potential of permeate decreased and increased respectively by applying the bubbles, while the effects were enhanced significantly when an electric field was further applied. Furthermore, three-dimensional fluorescence spectrum confirmed that the amount of membrane foulant was reduced significantly by the synergistic effect. This study proved that microparticles were affected by the slug flow and the electric field affected nanoparticles respectively. By this way, the novel approach was effective in enhancing membrane performance by tackling membrane foulants with different properties. This study also contributed to a better understanding of corresponding membrane fouling process in membrane bioreactors. [ABSTRACT FROM AUTHOR]