A highly pure biomethane stream (≈97% CH₄) was produced continuously under halo-alkaline conditions (pH > 9, 0.6 M Na⁺) from complex alkaline organic waste residue originating from biopolymer extraction from sewage sludge. During the proof-of-concept operation, the substrate was degraded with similar efficiency (40% of the volatile solids, VS) compared to neutral conditions (36% of the VS). Operational data was utilised in a technical evaluation to identify bottlenecks for full-scale implementation at an early stage of process development and for comparison to conventional biogas upgrading using pressure swing and membranes. Initially identified bottlenecks for alkaline fermentation were related to overcautious assumptions, while others could be technically solved. Alkaline fermentation offers an attractive method for supplying increasingly needed high-purity biomethane using various recalcitrant substrates that have undergone alkaline pre-treatment. This is more feasible than the conventional ex-situ biogas upgrading. Next, upscaling steps for alkaline fermentation should be pursued. Strategies for integrated CO₂ sequestration and nutrient recovery are outlined, which will offer additional benefits in the future.

Escalating global freshwater scarcity demands more energy-efficient and sustainable brackish water reverse osmosis (BWRO) desalination. This study demonstrates how integrating high-fidelity Artificial Neural Network (ANN) surrogates with a robust Non-dominated Sorting Genetic Algorithm II (NSGA-II) can deliver reliable multi-objective optimization for pilot-scale BWRO systems. Unlike conventional polynomial response surface models (RSM), which rely on static assumptions and often oversimplify dynamic membrane processes (and exhibit prediction errors of 15–25 %), the proposed framework directly learns the complex, nonlinear relationships among feed salinity, flow rate, pressure, temperature, and membrane type.

Validated against pilot-scale data with R2 > 0.99 and absolute average relative errors below 5 %, the ANN models accurately predict energy consumption (EC) and recovery (Re) under realistic operational conditions. Coupled with NSGA-II, the framework systematically generates Pareto-optimal operating regions that balance low EC (0.6 kWh/m³) with high Re (up to 80 %) while respecting fouling and scaling constraints. This multi-objective approach provides a flexible operating envelope, such as 3–4.5 LPM feed flow and 90–125 psi with higher-permeability membranes, surpassing the limitations of single-point optima. The optimized recovery represents a 3- to 5-fold increase over the typical factory baseline (∼15 %), translating to energy savings of >50 % and CO₂ emission reductions of 0.1–0.2 kg/m³. Sensitivity analysis confirms feed flow rate and pressure as dominant drivers of EC (31.3 % and 28.6 % relative factor) and membrane type and flow rate as primary influencers of Re (32.2 % and 30.2 %).

This optimum region approach surpasses the limitations of traditional single-point design optimization by providing flexible operating envelopes that accommodate seasonal feed variability, equipment aging, and membrane fouling. All models and the optimization framework are shared via an open-source repository to ensure full reproducibility and facilitate industrial adoption.

Overall, this AI-driven multi-objective optimization framework bridges the gap between theoretical performance and field-ready operation, laying the foundation for more adaptive, cost-effective, and climate-smart brackish water desalination. The modular approach is directly adaptable to multi-stage and hybrid systems, offering a scalable and resilient solution to urgent global water scarcity challenges.

Nitrification in biological wastewater treatment is a significant source of nitrous oxide (N2O), a potent greenhouse gas (GHG). There are some models that describe the biological N2O production process, but they don't include abiotic N2O production pathways which, remarkably, contribute up to 50% of the total N2O emissions under high nitrite (NO2-) conditions. This limitation frequently results in pronounced predictive biases under high influent ammonium (NH4+) and intermediate NO2- conditions (such as in the partial nitrification + Anammox system), leading to the misidentification of N2O emissions, undermining the development of effective mitigation strategies. To address this gap, a key abiotic N2O production pathway was integrated into an existing model of nitrification which includes biological N2O emissions. The upgraded model was systematically evaluated using literature-derived case studies, and can effectively predict the contributions of the abiotic pathway to N2O emissions (49%), compared to experimental data (51%). A local sensitivity analysis confirms that the upgraded model has a resilience to perturbations within most parameters, although very high concentrations of NO2- (>1,000 mg N/L) necessitate a precise calibration of ammonium oxidation to nitrite (the AOB process), in which related parameters can more easily be measured in experiments. Moreover, a global sensitivity analysis demonstrates that dissolved oxygen (DO) and alkalinity are the most sensitive of the four key environmental factors (NH4+, NO2-, DO and alkalinity) which control N2O emissions.

The theatre of activity of complex microbial communities underpins the Aerobic Granular Sludge (AGS) systems, resulting in efficient wastewater treatment. Here, we present the first meta-analysis of DNA sequencing data from both published and newly generated AGS samples, aiming to define the “core microbiota” of AGS reactors, consisting of bacteria, archaea, eukaryotes and DNA viruses consistently featured and shared across different scales and operational settings. Briefly, the results indicated that a sequencing depth of at least 10 GB is required to profile the majority of the AGS community, revealed the core taxa, detected the recurrent presence of the uncultured genus ADurb.Bin028 in full-scale reactors and identified Rotaria and Diploscapter, as well as the sessile ciliates Stentor and Thuricola, as the most abundant eukaryotes in AGS. In conclusion, this work provided a taxonomic overview of AGS’ common microbes and addressed potential technical caveats, aiming to establish a reference for future studies.

Activated sludge (AS) wastewater treatment generates substantial excess sludge which needs to be discarded and thereby increasing operational costs. Extracellular polymeric substances (EPS) within AS present a potential resource for recovery, reducing sludge volume and mass while adding value. Achieving this goal requires a better characterization of EPS, as the relationship between its composition and the microbial communities responsible for its production remains insufficiently understood. Here, we analysed extracted EPS from 16 wastewater treatment plants across 13 countries and 5 continents and found that alkaline extractable EPS yields varied widely (2.81–18.5 wt.% VSS). The microbial community composition of abundant species varied across plants and particularly across continents and did not correlate to the EPS yield. Only sludge retention time had a significant correlation with the EPS yield (p < 0.005). Traditional colorimetric assays failed to detect compositional trends of the EPS, but Fourier Transform Infrared (FTIR) analysis indicated that extracted EPS from biological phosphorus removal systems had higher lipid and polysaccharide content, while chemical phosphorus removal systems had higher relative protein content. Thus, FTIR proved effective for distinguishing extracted EPS composition, demonstrating its potential as a high-throughput characterization tool. These findings highlighted that the wastewater treatment design and operation may shape the functional groups in EPS when using the alkaline method. More investigations are needed to find possible correlations between the composition of extracted EPS and the microbial community structure. Overall, the study presents a baseline for the amount and overall composition of biopolymers that can be extracted from global AS plants for recovery.

The recovery of C, N, and P elements by sludge biorefinery potentially reduces operation costs and increases the extra benefits. Herein, we analyzed the elemental stoichiometry of C, N, and P and functional microbiome involved in enzymatic anaerobic fermentation. Enzymatic hydrolysis was observed to increase the release of C, N, and P into the sludge supernatants by 21.8 %–26.3 %. Metatranscriptome analysis indicated that enzymatic pretreatment enhanced the metabolism of the organic carbon degradation, ammonium conversion, and P solubilization in subsequent fermentation. Specifically, enzymatic pretreatment enhanced endogenous carbon hydrolase activity by 48.4 %–72.7 % and upregulated intra-C metabolic pathways, such as glycolysis and pyruvate metabolism. Ammonium transport and conversion were significantly increased by 4–6 fold, stimulating the synthesis of glutamine and endogenous amino acids. Additionally, enzymatic hydrolysis promoted phosphatase secretion and enhanced bacterial P uptake. These effects improved the recovery of C, N, and P as dentification carbon source and struvite by 13.7 %–41.8 % and the dry sludge production was reduced by 24.3 %–28.1 %. Life cycle assessment (LCA) indicated the shift of CO₂ emissions from net positive to net negative levels as compared to the conventional A²/O process. This study offers valuable insights into the redistribution and metabolism of various elements involved in the enzymatic anaerobic fermentation, and proposes the potential strategy to recovery C, N, and P from sewage via sludge biorefinery.

Fire hydrants are widely installed in drinking water distribution systems, where stagnant water forms multiple ‘high-risk zones’. The stagnant water quality at hydrant terminals has been poorly studied. Here we show that stagnant water exhibited an 18-fold increase in manganese, a 40-fold increase in total cell counts, a 13-fold increase in adenosine triphosphate and enrichment of opportunistic pathogens compared with flowing water. Notable changes were also observed in microbial communities and dissolved organic matter composition, including shifts in dominant bacterial taxa, transformation of saturated oxidized compounds and generation of unsaturated reduced compounds. This study also explored the ecological mechanisms underlying the covariation of microorganisms and dissolved organic matter after water stagnation. This finding provides an additional possibility for drinking water quality deterioration in drinking water distribution systems, highlighting the potential threat posed by stagnant water in non-consumer terminals (fire hydrants) to water safety.

Aerobic granular sludge (AGS) is an effective wastewater treatment widely applied worldwide for the removal of nutrients and organic matter. However, limited information is available on the effectiveness of full-scale AGS plants for removing organic micropollutants (OMP), particularly during wet weather. This study investigated the occurrence and removal of OMPs, including 19 pharmaceuticals and 2 industrial compounds, in a full-scale AGS plant during both dry and wet weather over one year. We selected a full-scale AGS plant located in Utrecht, the Netherlands as the targeted AGS plant, and collected monthly 24-hour composite water samples and grab sludge samples f rom May 2023 to April 2024. 21 OMPs were extracted from water and sludge samples and measured by LC/MS. Concentrations of ammonia and organic matter (both particulate and soluble) were measured with HACH Lange GMBH kits.

The results show that Influent concentrations of 5 pharmaceuticals and 1 industrial compound exceeded 1 ?g L-1, which were diluted by rainfall. Influent loadings of 7 OMPs (absolute OMP amount in ?g day -1) were significantly increased during wet weather, likely from sewage sediment resuspen sion and urban runoff. Average removal efficiencies of 11 compounds achieved greater than 20%, with 5 of them exceeding 50%, in the AGS plants. Simple linear regression results between OMP removal efficiencies and flow rates showed that biodegradable OMPs were more strongly affected by increased influent volumes (as indicated by steeper slopes) than OMPs primarily removed through sorption. Additionally, correlation analysis results showed that the removal of soluble organic matter was significantly correlated (p-value < 0.05) with the removal of 14 OMPs, suggesting that organic matter removal may be an indicator for OMP removal in the AGS plant. After AGS treatment, 8 compounds in the effluent remained above their predicted no-effect concentration levels, indicating potential ecological and human health risks in the receiving water. During wet weather, effluent OMP loadings increased mainly driven by reduced removal efficiency. Additionally, compared to activated sludge plants, the AGS plant exhibited comparable or slightly higher OMP removal efficiency during dry weather. Overall, this study is the first to investigate OMP removal during wet weather in a full-scale AGS plant and propose the potential impact of increased flow rates on biodegradable OMPs or OMPs mainly removed through sorption.

The global phosphorus challenge arises from the uneven distribution of phosphorus resources, environmental effects from phosphorus losses and unsustainable linear management. Despite progress in advanced phosphorus recycling, less than 1% of secondary phosphorus resources produced globally are recycled. In this Review, we comprehensively explore global barriers to phosphorus recycling. Manure (15–20 million tons P (MtP) yr−1), mining and fertilizer industry waste (6–12 MtP yr−1), wastewater (~3.7 MtP yr−1) and food waste (~1.2 MtP yr−1) are the major secondary phosphorus resources worldwide. In addition, accumulated legacy phosphorus in soil and sediment comprises a combined stock of more than 3,200 MtP. Phosphorus mismanagement and losses cost stakeholders US$265 billion annually, yet substantial barriers to phosphorus recycling remain. Key challenges to be overcome include low competitiveness of recycled phosphorus products, complex waste handling, limited legacy phosphorus recovery and fragmented collaboration among stakeholders. A shift is needed towards an integrated, systems-based approach that simultaneously addresses technical, economic and societal challenges. Transdisciplinary strategies and research will advance phosphorus recycling and the development of a sustainable, circular phosphorus economy. Incorporating the perspectives of diverse stakeholders will help drive increasingly sustainable phosphorus management.

Phosphorus runoff from agricultural land is a major driver of eutrophication, with manure serving as a significant source of phosphorus input. In regions such as the Netherlands, high livestock densities and limited land availability pose challenges for manure management, particularly in pig farming. Recovering phosphorus from manure and redistributing it to phosphorus-deficient areas offers a sustainable solution. This study explores phosphate recovery via vivianite (Fe₃(PO₄)₂·8H₂O) precipitation—a method previously demonstrated in municipal wastewater treatment plant sludge—and evaluates its applicability to pig manure. Vivianite formation was investigated in fresh, 4-month-aged, and digested pig manure, as well as in Thermal Hydrolysis Plant (THP) derived digested sewage sludge. A key finding is that high dissolved inorganic carbon (DIC) concentrations inhibit vivianite formation by promoting siderite (FeCO₃) precipitation. In digested manure, a DIC threshold of approximately 3 g/L HCO₃⁻ was identified, below which vivianite formation is favored. THP sludge, characterized by elevated DIC, exhibited similar inhibitory effects. More generally, vivianite was shown to form without significant competition with siderite if the DIC concentration is <2.5 times the iron concentration. Experimental results were compared with thermodynamic predictions using Visual MINTEQ and experiments in ultrapure water, revealing discrepancies which may be attributed to the ionic composition in environmental matrices. Strategies such as combining ammonia and DIC stripping or targeting fresh manure were shown to enhance vivianite formation. These findings can be used to propose the integration of vivianite-based phosphorus recovery into broader resource recovery frameworks, including biomethane production, ammonium recovery, and carbon capture.

The objective of this study was to treat different types of industrial wastewaters (milk processing wastewater, soft drink wastewater, and soybean oil plant wastewater) using modified configurations of a bioreactor called one-stage internal dual circulation airlift A2O (DCAL-A2O) bioreactor. The modification involved the use of physical barriers (baffle and packing media) to enhance the anoxic zone of the bioreactor. The study investigated the performance of bioreactors in simultaneously removing carbon, nitrogen, and phosphorus. The bioreactor was designed in three configurations: ordinary, baffled, and hybrid DCAL-A2O bioreactors, depending on the type of manipulation. Different operating conditions, such as hydraulic retention time (HRT), air flow rate (AFR), and anaerobic volume ratio (AVR), were examined simultaneously. The hybrid DCAL-A2O bioreactor was found to be highly suitable for wastewater treatment due to its superior biological performance, ease of operation, and cost-effectiveness when compared to two other bioreactors. The chosen bioreactor demonstrated high performance in terms of TCOD, TN, phosphorus removal efficiencies, and effluent turbidity. Specifically, it achieved removal efficiencies of 97.0% for TCOD, 92% for TN (with a concentration of 179.4 mg/L), 90% for phosphorus (with a concentration of 50.33 mg/L), and an effluent turbidity of 9 NTU. These results were obtained under optimal conditions, which included a HRT of 10 h, an AFR of 2 L/min, and an AVR of 0.464. The unique setup of the bioreactor demonstrated its undeniable ability to effectively treat wastewater from different feeding points. PCR tests confirmed the co-existence of multiple functional bacterial species, including AOB, NOB, denitrifying bacteria, anammox, PAOs, DPAOs, and GAOs. This provides strong evidence for concurrent removal of organics and nutrients in all three configurations of the integrated unit. In summary, this study emphasizes the need for ongoing research in energy efficiency to safeguard our environmental resources.

Extracellular Polymeric Substances (EPS) are ubiquitous in biological wastewater treatment (WWT) technologies like activated sludge systems, biofilm reactors, and granular sludge systems. EPS recovery from sludge potentially offers a high-value material for the industry. It can be utilized as a coating in slow-release fertilizers, as a bio-stimulant, as a binding agent in building materials, for the production of flame retarding materials, and more. P recovered within the extracted EPS is an intrinsic part of the recovered material that potentially influences its properties and industrial applications. P is present in EPS in different speciation (e.g., P esters, poly-P, ortho-P, etc.). Such P species are already intensively used in the chemical industry to enhance thermal stability, viscoelasticity, emulsification, water-holding capacity, and many other properties of some natural and petroleum-derived polymers. The translation of this knowledge to EPS is missing which prevents the full utilization of phosphorus in EPS. This knowledge could allow us to engineer EPS via phosphorus for specific target properties and applications. In this review, we discuss how P could affect EPS properties based on experiences from other industries and reflect on how these P species could be influenced during the EPS extraction process or in the WWTPs.

Optimizing resource use is essential for the survival and fitness of species in microbial communities ubiquitous in natural and engineered ecosystems. These ecosystems are often characterized by the simultaneous presence of multiple substrates such as volatile fatty acids, amino acids and sugars. Yet, the evaluation of metabolic potential for these microbial community members is predominantly based on single substrate utilisation. Metabolic and ecological implications of the interactions of multiple substrates, particularly in environments with changes in redox conditions and substrate availability, remain poorly understood. In this study, we investigate the metabolic interactions resulting from co-substrate utilization in polyphosphate-accumulating organisms within wastewater treatment systems. We combined experimental analysis of highly enriched “Ca. Accumulibacter” mixed cultures with genome-resolved metagenomics and conditional flux balance analysis (cFBA) to quantify the physiological relevance of co-substrate uptake. We observe that anaerobic co-substrate utilisation of acetate and aspartate result in metabolic interactions leading to optimized redox balance, reduced ATP losses and increased biomass yields by up to 8% compared to individual substrate use. Metabolic modelling revealed that these benefits emerge from the network topology, where the interaction of different metabolic routes gives rise to synergistic effects. Extending our analysis to additional substrate pairs, we classify metabolic interactions into three general types: (i) neutral, (ii) one-way synergistic and (iii) reciprocal synergistic. Our findings highlight the importance of metabolic interactions and cellular resource allocation strategies in dynamic microbial ecosystems. This study provides a broader ecological framework for understanding competitive metabolic strategies in environmental organisms. Co-substrate utilization can have direct implications for improving the yield or productivity of bioprocesses.

A Lactobacillus-rich vaginal microbiome is associated with a reduced risk for sexually transmitted diseases and adverse reproductive health outcomes, with Lactobacillus crispatus identified as particularly beneficial. This study investigated the nutritional requirements of two vaginal isolates, L. crispatus RL09 and RL10, and presents a chemically defined medium (CDM) that supports their growth. This study experimentally validated that L. crispatus relies on exogenous fatty acids, essential B vitamins, including riboflavin (B2), niacin (B3) and pantothenate (B5), and all eighteen amino acids for sustained growth. On one hand, this body of work adds to the physiological understanding of Lactobacilliaceae and lays the groundwork for future quantitative studies on L. crispatus. On the other hand, we have shown that L. crispatus exhibits a high metabolic dependency on its environment. These dependencies underscore the potential sensitivity of L. crispatus to nutrient variations, which may influence its ability to dominate and maintain a healthy vaginal ecosystem.

Polyhydroxyalkanoate (PHA) production is a promising technology fostering the spread of the circular bio-economy approach. However, the environmental implication of the process is usually neglected. This paper shows the results of a membrane-based PHA production pilot plant fed with no-pretreated waste activated sludge (WAS). The system was monitored for effluent water quality, nitrous oxide (N₂O), and PHA production by dynamic accumulation over a long-term period to assess the consistency of the results over several fluctuations. The experimental study was characterized by three C/N ratios of 9, 4.5, and 4 g COD/g N. The system achieved a stable and high removal efficiency for carbon and nitrogen (96.3 ± 2.6 % and 89.9 ± 6.7 %, respectively), despite the only legislation limit respected being the biological oxygen demand concentration discharge limits imposed by 2020/741/EU. Low N₂O gaseous and liquid concentrations were achieved over the 200-day experimental period, never exceeding 0.52 mg N₂O-N/L. Despite the high concentration, the N₂O emission factor accounted for only 0.21 ± 0.14 % of the influent nitrogen. Finally, the system produced an average of 36.3 ± 1.8 % g PHA/g VSS with a storage yield of up to 0.42 g COD_PHA/g COD_VFA. The system revealed a high stability over a long-term experimental period, achieving a considerable amount of PHA while maintaining a low N₂O emission. Promising effluent water quality was achieved, highlighting the potential of applying the water reuse practices.

The hydrolysis of structural extracellular polymeric substances (St-EPS) is considered a major limiting step in the anaerobic fermentation of waste activated sludge (WAS). However, the degradation of heteropolysaccharides, characterized by complex monomers of uronic acids and neutral saccharides in St-EPS, has rarely been reported. In this study, microbial-produced xanthan-like heteropolysaccharides, characterized by a blue filamentary film, were identified. The xanthan-producing bacteria comprised ∼7.2% of total genera present in WAS. An xanthan-degrading consortium (XDC) was enriched in an anaerobic batch reactor. This consortium could degrade Xanthan for over 90% and disrupt the gel structure of xanthan while promoting methane production from WAS by 29%. The xanthan degradation network consisting of extracellular enzymes and bacteria was elucidated by combining high-throughput sequencing, metagenomic, and metaproteomic analyses. Five enzymes were identified as responsible for hydrolyzing xanthan to monomers, including xanthan lyase, β-D-glucosidase, β-D-glucanase, α-D-mannosidase, and unsaturated glucuronyl hydrolase. Seven genera, including Paenibacillus (0.2%) and Clostridium (3.1%), were identified as key bacteria excreting one to five of the aforementioned enzymes. This study thus provides insights into the complex conversions in anaerobic digestion of WAS and gives a foundation for future optimization of this process.

Identifying structural proteins within the extracellular polymeric substances (EPS) will provide a better understanding of the stability of aerobic granular sludge (AGS) and biofilms in general. In this work, an abundant surface protein was identified and localized in the extracellular matrix of seawater-adapted AGS. Granules with good phosphate removal were cultivated in a sequencing batch bubble column reactor with acetate as a carbon source dissolved in seawater. “Candidatus Accumulibacter” was observed as the most dominant community member through fluorescent in-situ hybridization. A surface protein of 74.5 kDa was identified in the EPS extract of the seawater-adapted AGS by SDS-PAGE and mass spectrometry. The surface protein was produced by an Accumulibacter species and showed homology to S-layer proteins. A type 1 secretion system was found adjacent to the gene encoding for the surface protein, suggesting a possible export system. Antibodies generated from a unique peptide of the surface protein confirmed the extracellular location of the surface protein. Microscopy observations with antibody staining showed the surface protein forms dense structures within the Accumulibacter microcolonies and larger fiber structures around the microcolonies. These observations highlight the importance of the protein for the structural properties of the granule. To detect more structural proteins in the EPS, optimization of the EPS extraction and in situ imaging validation methods are essential.

Water treatment facilities are bound to incorporate resource recovery in the near future, necessitating novel economic assessments that capture the full economic potential of these systems. This study evaluates three cost calculation methods—Non-allocation, Economic allocation, and Dual allocation— to improve the accuracy of the Levelized Cost for multi-product desalination and brine treatment plants. The methods were tested across three technical scenarios: Sc1) maximum water recovery, Sc2) integrated desalination with brine treatment for resource recovery and Sc3) electricity-based desalination for chemical recovery. Results reveal that the traditional Non-allocation method tends to overestimate production costs by uniformly applying fixed costs across products, leading to inflated levelized costs. The Economic allocation approach reduces the levelized costs of water and other recovered products by up to 81 %, enhancing competitiveness with conventional production methods. The Dual allocation approach is most effective for recovered salts and chemicals, ensuring fair cost distribution and fostering competitiveness with linear systems. Sc2 is the most economically feasible under both novel approaches due to its balanced mix of high-value products and moderate operational costs. These findings suggest that cost calculation methods should align with plant objectives: Economic allocation for scenarios prioritizing water recovery and Dual allocation for maximizing the value of salts and chemicals. This study provides a foundation for tailored economic assessments and guides plant design and investment decisions.

The post-pandemic world still faces ongoing COVID-19 infections, although international travel has returned to pre-pandemic conditions. Wastewater-based epidemiology (WBE) is considered an efficient tool for the population-wide surveillance of COVID-19 infections during the pandemic. However, the performance of WBE in post-pandemic era with travel restrictions lifted remains unknown. Utilizing weekly county-level wastewater surveillance data from June 2021-November 2022 for 222 counties in 49 states (covering 104 million people) in the United States of America, we retrospectively evaluated the correlations between SARS-CoV-2 RNA (CRNA) and reported cases, as well as the impacts of international air travel, demographics, socioeconomic aspects, test accessibility, epidemiological, and environmental factors on reported cases under the corresponding CRNA. The lifting of travel restrictions in June 2022, shifted the correlation between CRNA and COVID-19 incidence in the following 7-day and 14-day from 0.70 (IQR: 0.30–0.88) in June 2021-May 2022 (pandemic) to 0.01 (IQR: -0.31–0.36) in June-November 2022 (post-pandemic), and from 0.74 (IQR: 0.31–0.90) to -0.01 (IQR: -0.38–0.45), respectively. Besides, after lifting the travel restrictions, under the same CRNA, the reported case numbers were impacted by many factors, including the variations of international passengers, test accessibility, Omicron prevalence, ratio of population aged between 18 and 65, minority vulnerability, and healthcare system. This highlights the importance of demographics, infection testing, variants and socioeconomic status on the accuracy and implication of WBE to monitor COVID-19 infection status in post-pandemic era. Our findings facilitate the public health authorities to dynamically adjust their WBE-based tools/strategies to the local contexts to achieve optimal community surveillance.

The synthesis of chemically derived bituminous-based activated carbons (ACs) was conducted in this research. The study examined the efficacy of the KOH-2 modified AC by conducting batch experiments under different operating settings. Pollutant concentration, adsorbent dosage and contact time were considered as variables. Bovine serum albumin (BSA), dextrose, and methylene blue (MB) were used as model substances to represent protein, carbon, and textile dyes, respectively. Under optimal conditions, the activated carbon modified with a 2:1 impregnation ratio using KOH showed the best performance among two other ACs, therefore, that was introduced as chosen AC. The optimal parameters were determined as pollutant concentration, adsorbent dosage and contact time obtained to be 600 mg/L, 0.22 g/L and 220 min; 200 mg/L, 0.6 g/L and 180 min; 200 mg/L, 1 g/L and 196 min for MB, BSA and dextrose, respectively. This AC obtained the highest adsorption capacity of 2710.6, 283, and 273 mg/g adsorbing MB, BSA and dextrose, respectively. In the following, column studies were conducted using biologically treated wastewater obtained from a new one-stage hybrid internal circulation airlift A2O bioreactor to eliminate soluble microbial products (SMP). It was seen that the adsorption column, which was filled with the AC under optimal experimental conditions (bed height of 4.5 cm and solution flow rate of 5 mL/min), resulted in a decrease in residual organic substances from 35 mg-TOC/L to 6.6 mg-TOC/L. It is worth mentioning that the utilization of an integrated approach involving sophisticated biological treatment and post-treatment technology has demonstrated efficacy in the elimination of residual organic substances.