Role of membrane fouling layer in microbial fuel cell-membrane bioreactor (MFC-MBR) for controlling sulfamethoxazole and corresponding resistance genes.

Integrated MFC-MBR systems effectively remove antibiotics and control the release of antibiotic resistance genes (ARGs). However, the fouling layers on membranes can potentially act as reservoirs for ARGs. This study aims to elucidate the roles of membrane fouling layers and levels in influencing sulfamethoxazole (SMX) removal and ARGs control within an MFC-MBR system. Our findings demonstrate that low-intensity bioelectricity (400-500 mV) mitigates membrane fouling rates. The membrane fouling layer significantly contributes (39%-47%) to SMX removal compared to the cathode/anode zones. Higher extracellular polymeric substance (EPS) content and a lower protein/polysaccharide (PN/PS) ratio favor SMX removal by the membrane fouling layer. Across different levels of membrane fouling, the PN/PS ratio rather than EPS concentration plays a crucial role in SMX removal efficiency. The MFC-MBR with low fouling achieved superior SMX removal (69.1%) compared to medium (54.3%) and high fouling conditions (46.8%). The presence of ARGs in the membrane fouling layer increases with fouling formation, with intrinsic ARGs prevailing. Dense membrane fouling layers effectively retain ARGs, thereby reducing the risk of extracellular ARGs (eARGs) diffusion in effluents. These results provide insights into controlling ARGs in MFC-MBR systems and underscore the significant role of membrane fouling layers in antibiotics and ARGs removal.

An Innovative Surface Modification Technique for Antifouling Polyamide Nanofiltration Membranes.

In this study, we developed a novel surface coating technique to modify the surface chemistry of thin film composite (TFC) nanofiltration (NF) membranes, aiming to mitigate organic fouling while maintaining the membrane's permselectivity. We formed a spot-like polyester (PE) coating on top of a polyamide (PA) TFC membrane using mist-based interfacial polymerization. This process involved exposing the membrane surface to tiny droplets carrying different concentrations of sulfonated kraft lignin (SKL, 3, 5, and 7 wt %) and trimesoyl chloride (TMC, 0.2 wt %). The main advantages of this surface coating technique are minimal solvent consumption (less than 0.05 mL/cm2) and precise control over interfacial polymerization. Zeta potential measurements of the coated membranes exhibited enhancements in negative charge compared to the control membrane. This enhancement is attributed to the unreacted carboxyl functional groups of the SKL and TMC monomers, as well as the presence of sulfonate groups (SO3) in the structure of SKL. AFM results showed a notable decrease in membrane surface roughness after polyester coating due to the slower diffusion of SKL to the interface and a milder reaction with TMC. In terms of fouling resistance, the membrane coated with a polyester composed of 7 wt % SKL showed a 90% flux recovery ratio (FRR) during Bovine Serum Albumin (BSA) filtration, showing a 15% improvement compared to the control membrane (PA). PE-coated membranes provided stable separation performance over 40 h of filtration. The sodium chloride rejection and water flux displayed minimal variations, indicating the robustness of the coating layer. The final section of the presented study focuses on assessing the feasibility of scaling up and the cost-effectiveness of the proposed technique. The demonstrated ease of scalability and a notable reduction in chemical consumption establish this method as a viable, environmentally friendly, and sustainable solution for surface modification.

What lies underneath: Comparison among beach litter in the underwater bathing area and exposed beach.

The standard techniques for monitoring beach litter focus on the litter that is accumulated on beaches. Therefore, the underwater bathing area is usually overlooked. Our study aims to start the discussion about the litter in the bathing area, an important connection between the exposed beach and the ocean. We aimed to compare sampling methodologies between the underwater bathing area and the exposed beach. We highlighted litter's similarities and differences regarding the amount, material, possible sources, and interaction with the biota. We also performed a brand audit on the underwater bathing area litter. In the underwater region, 106 items were collected while 1706 items were collected from the exposed beach region. Plastic was the dominant type of material in both sites, exposed beach (89.92 %) and bathing area (83.96 %). The litter's possible source was different. In the underwater bathing area was more related to food packages (couscous, rice). On the other hand, litter on the exposed beach was associated with beach use (single-use plastic such as plastic cups). The brand audit identified 21 companies, whereby most brands were Brazilian and food-related. Regarding interactions with the biota, the litter in the bathing area had more bio-fouling (87.73 %) than the litter collected on the exposed beach (10.00 %). Information about bathing area litter can be useful to draw different management strategies. Due to the differences in litter types and behavior between the two sites, the same mitigation strategies might not be equally efficient.

New insights into membrane fouling in coagulation-ultrafiltration by cake characteristics analysis: A case study with PACl-Al13 and PACl.

Membrane fouling is a bottleneck issue that hindered the further application of ultrafiltration technology. To alleviate membrane fouling, coagulation-ultrafiltration (C-UF) process using polyaluminum chloride (PACl) and PACl-Al13 with high proportion of Al13O4(OH)247+ as coagulants, respectively, were investigated at various pH conditions. Results indicated that an increase in solution pH contributed to larger floc size and looser floc structure for both PACl and PACl-Al13. It was conducive to the formation of more porous cake, as evidenced by mean pore area and pore area distribution of cake, leading to lower reversible fouling. Furthermore, humic acid (HA) removal presented a trend of first increasing and then decreasing with the increase of pH. The optimal HA removal was achieved at pH 6 regardless of coagulant type, suggesting that the slightest irreversible fouling should be occurred at this point. Interestingly, the irreversible fouling with PACl coagulant achieved a minimum value at pH 9, while the minimal irreversible fouling with PACl-Al13 was observed at pH 6. We speculated that the cake formed by PACl could further intercept HA prior to UF process at alkaline pH. Furthermore, compared with PACl, PACl-Al13 had a stronger charge neutralization ability, thus contributing to more compact floc structure and higher HA removal at various pH conditions. By UF fractionation measurement, higher HA removal for PACl-Al13 was due to higher removal of HA with molecular weight less than 50 kDa.

High biomass yields of Chlorella protinosa with efficient nitrogen removal from secondary effluent in a membrane photobioreactor.

Further treatment of secondary effluents before their discharge into the receiving water bodies could alleviate water eutrophication. In this study, the Chlorella proteinosa was cultured in a membrane photobioreactor to further remove nitrogen from the secondary effluents. The effect of hydraulic retention time (HRT) on microalgae biomass yields and nutrient removal was studied. The results showed that soluble algal products concentration reduced in the suspension at low HRT, thereby alleviating microalgal growth inhibition. In addition, the lower HRT reduced the nitrogen limitation for Chlorella proteinosa's growth through the phase-out of nitrogen-related functional bacteria. As a result, the productivity for Chlorella proteinosa increased from 6.12 mg/L/day at an HRT of 24 hr to 20.18 mg/L/day at an HRT of 8 hr. The highest removal rates of 19.7 mg/L/day, 23.8 mg/L/day, and 105.4 mg/L/day were achieved at an HRT of 8 hr for total nitrogen (TN), ammonia, and chemical oxygen demand (COD), respectively. However, in terms of removal rate, TN and COD were the largest when HRT is 24 hr, which were 74.5% and 82.6% respectively. The maximum removal rate of ammonia nitrogen was 99.2% when HRT was 8 hr.

Integrating gravity-driven ceramic membrane filtration with hydroponic system for nutrient recovery from primary municipal wastewater.

In this study, a gravity-driven membrane (GDM) filtration system and hydroponic system (cultivating basil and lettuce) were combined for nutrient recovery from primary municipal wastewater. The GDM system was optimized by increasing the periodic air sparging flow rate from 1 to 2 L/min (∼15 hr per 3-4 days), resulting in a ∼52% reduction of irreversible fouling. However, the total fouling was not alleviated, and the water productivity remained comparable. The GDM-filtrated water was then delivered to hydroponic systems, and the effects of hydroponic operation conditions on plant growth and heavy metal uptake were evaluated, with fertilizer- and tap water-based hydroponic systems and soil cultivation system (with tap water) for comparison. It was found that (i) the hydroponic system under batch mode facilitated to promote vegetable growth with higher nutrient uptake rates compared to that under flow-through feed mode; (ii) a shift in nutrient levels in the hydroponic system could impact plant growth (such as plant height and leaf length), especially in the early stages. Nevertheless, the plants cultivated with the GDM-treated water had comparable growth profiles to those with commercial fertilizer or in soils. Furthermore, the targeted hazard quotient levels of all heavy metals for the plants in the hydroponic system with the treated water were greatly lower than those with the commercial fertilizer. Especially, compared to the lettuce, the basil had a lower heavy metal uptake capability and displayed a negligible impact on long-term human health risk, when the treated water was employed for the hydroponic system.

Treatment of azo dye-containing wastewater in a combined UASB-EMBR system: Performance evaluation and membrane fouling study.

This work investigated the treatment of azo dye-containing wastewater in an upflow anaerobic sludge blanket (UASB) reactor combined with an electro-membrane bioreactor (EMBR). Current densities of 20 A m-2 and electric current exposure mode of 6'ON/30'OFF were applied to compare the performance of the EMBR to a conventional membrane bioreactor (MBR). The results showed that dye (Drimaren Red CL-7B) removal occurred predominantly in the UASB reactor, which accounted for 57% of the total dye removal achieved by the combined system. When the MBR was assisted by electrocoagulation, the overall azo dye removal efficiency increased from 60.5 to 67.1%. Electrocoagulation batch tests revealed that higher decolorization rates could be obtained with a current density of 50 A m-2. Over the entire experimental period, the combined UASB-EMBR system exhibited excellent performance in terms of chemical oxygen demand (COD) and NH4+-N removal, with average efficiencies above 97%, while PO43--P was only consistently removed when the electrocoagulation was used. Likewise, a consistent reduction in the absorption spectrum of aromatic amines was observed when the MBR was electrochemically assisted. In addition to improving the pollutants removal, the use of electrocoagulation reduced the membrane fouling rate by 68% (0.25-0.08 kPa d-1), while requiring additional energy consumption and operational costs of 1.12 kWh m-3 and 0.32 USD m-3, respectively. Based on the results, it can be concluded that the combined UASB-EMBR system emerges as a promising technological approach for textile wastewater treatment.

Cyclodextrin-modified PVDF membranes with improved anti-fouling performance.

The design of hydrophilic polyvinylidene fluoride (PVDF) membranes with anti-fouling properties has been explored for decades. Surface modification and blending are typical strategies to tailor the hydrophilicity of PVDF membranes. Herein, cyclodextrin was used to improve the antifouling performance of PVDF membranes. Cyclodextrin-modified PVDF membranes were prepared by coupling PVDF amination (blending with branched polyethyleneimine) and activated cyclodextrin grafting. The blending of PEI in the PVDF casting solution preliminarily aminated the PVDF, resulting in PEI-crosslinked/grafted PVDF membranes after phase inversion. Aldehydes groups on cyclodextrin, introduced by oxidation, endow cyclodextrin to be grafted on the aminated PVDF membrane by the formation of imines. Borch reduction performed on the activated cyclodextrin-grafted PVDF membrane converted the imine bonds to secondary amines, ensuring the membrane stability. The resulting membranes possess excellent antifouling performance, with a lower protein adsorption capacity (5.7 µg/cm2, indicated by Bovine Serum Albumin (BSA)), and a higher water flux recovery rate (FRR = 96%). The proposed method provides a facial strategy to prepare anti-fouling PVDF membranes.

Amphiphilic Polyelectrolyte Complexes for Fouling-Resistant and Easily Tunable Membranes.

Commercial membranes today are manufactured from a handful of membrane materials. While these systems are well-optimized, their capabilities remain constrained by limited chemistries and manufacturing methods available. As a result, membranes cannot address many relevant separations where precise selectivity is needed, especially with complex feeds. This constraint requires the development of novel membrane materials that offer customizable features to provide specific selectivity and durability requirements for each application, enabled by incorporating different functional chemistries into confined nanopores in a scalable process. This study introduces a new class of membrane materials, amphiphilic polyelectrolyte complexes (APECs), comprised of a blend two distinct amphiphilic polyelectrolytes of opposite charge that self-assemble to form a polymer selective layer. When coated on a porous support from a mixture in a nonaqueous solvent, APECs self-assemble to create ionic nanodomains acting as water-conducting nanochannels, enveloped within hydrophobic nanodomains, ensuring structural integrity of the layer in water. Notably, this approach allows precise control over selectivity without compromising pore size, permeability, or fouling resistance. For example, using only one pair of amphiphilic copolymers, sodium sulfate rejections can be varied from >95% to <10% with no change in effective pore size and fouling resistance. Given the wide range of amphiphilic polyelectrolytes (i.e., combinations of different hydrophobic, anionic, and cationic monomers), APECs can create membranes with many diverse chemistries and selectivities. Resultant membranes can potentially address precision separations in many applications, from wastewater treatment to chemical and biological manufacturing.

Ferrate(VI)-based oxidation for ultrafiltration membrane fouling mitigation in shale gas produced water pretreatment: Role of high-valent iron intermediates and hydroxyl radicals.

Ultrafiltration (UF) is increasingly used in the pretreatment of shale gas produced water (SGPW), whereas severe membrane fouling hampers its actual operation. In this work, ferrate(VI)-based oxidation was proposed for membrane fouling alleviation in SGPW pretreatment, and the activation strategies of calcium peroxide (CaO2) and ultraviolet (UV) were selected for comparison. The findings indicated that UV/Fe(VI) was more effective in removing fluorescent components, and the concentration of dissolved organic carbon was reduced by 24.1 %. With pretreatments of CaO2/Fe(VI) and UV/Fe(VI), the terminal specific membrane flux was elevated from 0.196 to 0.385 and 0.512, and the total fouling resistance diminished by 52.7 % and 76.2 %, respectively. Interfacial free energy analysis indicated that the repulsive interactions between pollutants and membrane were notably enhanced by Fe(VI)-based oxidation, thereby delaying the deposition of cake layers on the membrane surface. Quenching and probe experiments revealed that high-valent iron intermediates (Fe(IV)/Fe(V)) played significant roles in both CaO2/Fe(VI) and UV/Fe(VI) processes. Besides, hydroxyl radicals (•OH) were also important reactive species in the UV/Fe(VI) treatment, and the synergistic effect of Fe(IV)/Fe(V) and •OH showed a positive influence on SGPW fouling mitigation. In general, these findings establish a theoretical underpinning for the application of Fe(VI)-based oxidation for UF membrane fouling mitigation in SGPW pretreatment.

Effectiveness of cloth media filters on mitigating membrane fouling in anaerobic filter membrane bioreactors.

Membrane fouling is a persistent challenge that has impeded the broader application of anaerobic membrane bioreactors (AnMBRs). To mitigate membrane fouling, between the outlet of the UASB anaerobic bioreactor and the PVDF membrane to form the anaerobic filter membrane bioreactor (AnFMBR) system. Through comprehensive experiments, the optimal pore size for cloth filters was determined to be 50 µm. A comprehensive assessment over 140 days of operation shows that the novel AnFMBR had significantly greater resistance to membrane pollution than the traditional AnMBR. The AnFMBR system membrane tank exhibited lower mixed liquor suspended solid and mixed liquor volatile suspended solid concentrations, smaller sludge particle sizes, increased hydrophilicity of sludge flocs, and optimized microbial community distribution compared to those of conventional AnMBRs. The total solids foulant accumulation rate in the AnMBR was 5.1 g/m2/day, while in the AnFMBR, the rate was 2.4 g/m2/day, marking a 53.7 % decrease in fouling rate for the AnFMBR compared with the AnMBR. This decrease indicates that integrating the filtration assembly significantly lowered the rate of solid foulant accumulation on the membrane surface, primarily by controlling the buildup of solid foulants in the cake layer, thereby alleviating membrane fouling. AnFMBR compared to AnMBR, the membrane fouling rate halved, effectively doubled the interval between membrane cleaning from seven days, as observed in the AnMBR system, to fourteen days. These findings underscore the potential of integrating cloth media filters into AnMBRs to improve operational efficiency, economic viability, and sustainability.

"Coir Raincoat"-Boosted Biomimetic Hydrogel for Efficient Solar Desalination and Wastewater Purification.

Solar-driven interfacial evaporation is an efficient method for purifying contaminated or saline water. Nonetheless, the suboptimal design of the structure and composition still necessitates a compromise between evaporation rate and service life. Therefore, achieving efficient production of clean water remains a key challenge. Here, a biomimetic dictyophora hydrogel based on loofah/carbonized sucrose@ZIF-8/polyvinyl alcohol is demonstrated, which can serve as an independent solar evaporator for clean water recovery. This special structural design achieves effective thermal positioning and minimal heat loss, while reducing the actual enthalpy of water evaporation. The evaporator achieves a pure water evaporation rate of 3.88 kg m-2 h-1 and a solar-vapor conversion efficiency of 97.16% under 1 sun irradiation. In comparison, the wastewater evaporation rate of the evaporator with ZIF-8 remains at 3.85 kg m-2 h-1 for 30 days, which is 16.3% higher than the light irradiation without ZIF-8. Equally important, the evaporator also showcases the capability to cleanse water from diverse sources of contaminants, including those with small molecules, oil, heavy metal ions, and bacteria, greatly improving the lifespan of the evaporator.

Interrupting marine fouling with active buffered coatings.

Biofouling on marine surfaces causes immense material and financial harm for maritime vessels and related marine industries. Previous reports have shown the effectiveness of amphiphilic coating systems based on poly(dimethylsiloxane) (PDMS) against such marine foulers. Recent studies on biofouling mechanisms have also demonstrated acidic microenvironments in biofilms and stronger adhesion at low-pH conditions. This report presents the design and utilization of amphiphilic polymer coatings with buffer functionalities as an active disruptor against four different marine foulers. Specifically, this study explores both neutral and zwitterionic buffer systems for marine coatings, offering insights into coating design. Overall, these buffer systems were found to improve foulant removal, and unexpectedly were the most effective against the diatom Navicula incerta.

Modification of polyvinylidene fluoride membrane with ciprofloxacin to improve the bacteriostatic performance.

The common polyvinylidene fluoride (PVDF) membrane itself is susceptible to membrane fouling, especially biofouling, which is a serious threat. In this study, PVDF membrane was modified with ciprofloxacin (CIP) through co-blending to investigate the filtration properties, bacterial inhibition and fouling resistance. Modified membranes were prepared by adding 0.3 g (MC0.3), 0.6 g (MC0.6), 0.9 g (MC0.9) and 1.2 g (MC1.2) CIP per 100 g casting solution. Among these modified membranes, MC0.6 showed the best filtration performances, with the pure water flux stabilized at about 416.67 L/(m2·h) and bovine serum albumin (BSA) rejection of 92.0% at a trans-membrane pressure of 0.1 MPa. The pore size was reduced, the average roughness was reduced to 29.4 nm, the contact angle was lowered to 68.9°, and the hydrophilicity was greatly improved. The width of the inhibition circle produced by MC0.6 was 0.35-0.45 mm, and the modified membrane showed good inhibition of non-specific bacteria and algal removal during urban river water filtration. The rejection of BSA was increased by 16.32% compared to the base membrane and the adsorption rate for BSA was reduced by 68.45%. In addition, the removal of conventional pollutants in urban river water by the modified membranes for was also improved. Compared with that of the base membrane, the removal of TN, NH3-N, TP and COD by MC0.6 was increased by 10.58%, 12.45%, 15.44% and 13.53%. The results showed that CIP co-blending modified PVDF membrane could effectively improve membrane performances and has good value for water treatment.

Fouling behavior of BTEX in petrochemical wastewater treated by nanofiltration (NF).

Membrane fouling generated by small molecular-weight aromatic compounds with poor biodegradability is a major barrier to advanced petrochemical wastewater treatment using nanofiltration (NF) technology. In this study, the fouling behavior of ten BTEX with different substituent existing in petrochemical wastewater on the NF membrane was systematically investigated. By examining the effect of the number, position, and type of substituents on the permeability of NF membranes and membrane resistance analysis, combined with XDLVO theory and correlation analysis, we found that stronger dipole-dipole interactions of BTEX with higher polarity and hydrogen bonding effects between substituents and the membrane surface were verified to be the main forces driving the attachment to the surface of membranes. Furthermore, by analyzing the effect of common inorganic ions in petrochemical wastewater on membrane fouling, it was found that electron-donating substituents (-CH3, -C2H5, and -NH2) enhanced the electron cloud density of the benzene ring, a process that exacerbated membrane fouling by strengthening electrostatic interactions between the benzene ring and Ca2+ ions. The fouling potential of electron-withdrawing substituted (-NO2, -OH) BTEX exhibited the opposite trend. Overall, this study provides a theoretical basis for developing effective membrane fouling control strategies in NF advanced treatment of petrochemical wastewater. ENVIRONMENTAL IMPLICATION: Aromatic chemicals in petrochemical effluent are difficult to degrade, and their accumulation will cause significant harm to humans and ecological systems. Determine the composition of small molecule BTEX in petrochemical wastewater, gain an in-depth comprehension of the membrane fouling behavior of nanofiltration membrane filtration, identify the primary forces causing irreversible membrane surface fouling using experimental data and model fitting, and propose viable anti-fouling membrane modification strategies. Establish a technical foundation for membrane fouling management in the long-term operation of petrochemical wastewater membrane treatment.

Comparison of UV/PS and VUV/PS as ultrafiltration pretreatment: Performance, mechanisms, DBPs formation and toxicity assessment.

Ultrafiltration (UF) is widely used in drinking water plants, nevertheless, it still encounters challenges stemming from inevitable membrane fouling caused by natural organic matter (NOM). Herein, this work applied VUV/PS as UF membrane pretreatment and used UV/PS for comparison. VUV/PS system exhibited superior ability in removing NOM compared to UV/PS system. HO and SO4- played crucial roles in the degradation. [SO4-]ss was notably higher than [HO]ss in the systems, yet HO was of greater significance. [HO]ss and [SO4-]ss in the VUV/PS process were remarkably higher than those in the UV/PS process, due to the function of 185 nm photons. VUV/PS pretreatment basically recovered flux and effectively reduced fouling resistance, with better performance than UV/PS. Fouling mechanism was dominated by multiple mechanisms after UV/PS pretreatment, whereas it was transformed into pore blockage after VUV/PS pretreatment. Moreover, the UF effluent quality after VUV/PS pretreatment outperformed that of UV/PS but fell short of that without pretreatment, possibly due to the generation of abundant low MW substances under the action of HO and SO4-. After chlorine disinfection, UV/PS and VUV/PS pretreatments increased the DBPs production and cytotoxicity. Specifically, oxidant PS affected the membrane surface morphology and fouling behaviors, and had no obvious effect on interception performance and mechanical properties. In actual water treatment, VUV/PS and UV/PS pretreatments exhibited excellent performance in alleviating membrane fouling, improving water quality, and reducing DBPs formation and acute toxicity.

Alleviation of RO membrane fouling in wastewater reclamation plants using an enhanced acid-base chemical cleaning method.

Membrane fouling has always been a critical constraint in the operation of the reverse osmosis (RO) process, and chemical cleaning is essential for mitigating membrane fouling and ensuring smooth operation of the membrane system. This paper presents an optimized chemical cleaning method for the efficient cleaning of RO membranes in full-scale applications. Compared to the regular cleaning method (cleaning with 0.1 % NaOH + 1 % ethylenediaminetetraacetic acid + 0.025 % sodium dodecyl benzene sulfonate followed by 0.2 % HCl), the optimized cleaning method improves the cleaning efficiency by adding sodium chloride to the alkaline cleaning solution and citric acid to the acid cleaning solution. Notably, the membrane flux recovery rate with the optimized cleaning method is 45.74 %, and it improves the cleaning efficiency by 1.65 times compared to the regular cleaning method. Additionally, the optimized cleaning method removes 30.46 % of total foulants (organic and inorganic), which is 2.11 times higher than the regular cleaning method. The removal of inorganic ions such as Fe, Ca, and Mg is significantly improved with the optimized cleaning method. For organic matter removal, the optimized cleaning method effectively removes more polysaccharides, proteins, and microbial metabolites by disrupting the complex structures of organic matter. Furthermore, it also changes the microbial community structure on the RO membrane surface by eliminating microorganisms that cannot withstand strong acids, bases, and high salt environments. However, Mycobacterium can adapt to these harsh conditions, showing a relative abundance of up to 84.13 % after cleaning. Overall, our results provide a new chemical cleaning method for RO membranes in full-scale applications. This method effectively removes membrane foulants and enhances the understanding of the removal characteristics of foulants on RO membrane surfaces by chemical cleaning.

Anaerobic membrane bioreactors for municipal wastewater: Progress in resource and energy recovery improvement approaches.

Anaerobic membrane bioreactor (AnMBR) offer promise in municipal wastewater treatment, with potential benefits including high-quality effluent, energy recovery, sludge reduction, and mitigating greenhouse gas emissions. However, AnMBR face hurdles like membrane fouling, low energy recovery, etc. In light of net-zero carbon target and circular economy strategy, this work sought to evaluate novel AnMBR configurations, focusing on performance, fouling mitigation, net-energy generation, and nutrients-enhancing integrated configurations, such as forward osmosis (FO), membrane distillation (MD), bioelectrochemical systems (BES), membrane photobioreactor (MPBR), and partial nitrification-anammox (PN/A). In addition, we highlight the essential role of AnMBR in advancing the circular economy and propose ideas for the water-energy-climate nexus. While AnMBR has made significant progress, challenges, such as fouling and cost-effectiveness persist. Overall, the use of novel configurations and energy recovery strategies can further improve the sustainability and efficiency of AnMBR systems, making them a promising technology for future sustainable municipal wastewater treatment.

Preventing biofouling in microalgal photobioreactors.

Photobioreactors (PBRs) are used to grow the light-requiring microalgae in diverse commercial processes. Often, they are operated as continuous culture over months period. However, with time, biofouling layer develops on the inner surfaces of their walls. The fouling layer formation deteriorates the PBR performance as foulants reduce light penetration in it. Light is essential for photosynthetic cultures, and a deterioration in lighting adversely impacts algae growth and biomass productivity. Fouling requires a frequent shutdown to clean the PBR and add to the environmental impact of the operation by generating many wastewaters contaminated with the cleaning chemicals. Antibiofouling coatings could be used to modify the surfaces of existing and future PBRs. Therefore, transparent and non-toxic fouling-release coatings, produced using hydrogel technology, could transform the existing PBRs into efficient and enduring microalgae culture systems, requiring only the application of the coating to the inner walls, without additional investments in new PBRs.

Combining descriptive and predictive modeling to systematically design depth filtration-based harvest processes for biologics.

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.