Search Results (1,853)

Wastewater treatment plants (WWTPs) are important interfaces for the persistence and dissemination of antimicrobial resistance genes (ARGs) in the environment. This study investigated colistin resistance and the presence of mobile colistin resistance (mcr) genes in Enterobacterales isolated from a poultry slaughterhouse WWTP in Brazil. Samples were collected from raw sewage, an equalization tank, and treated effluent. A total of 27 Enterobacter spp. isolates were identified, of which 70.4% showed resistance to colistin (MIC range: 2 to ≥512 mg/L). PCR screening detected mcr-1 in two isolates and mcr-10 in three isolates distributed across all treatment stages, including the final effluent. Whole-genome sequencing of a representative isolate from treated effluent identified Enterobacter vonholyi ST3343, carrying a plasmid-borne mcr-10 gene on an ~107 kb IncFII(Yp) plasmid, along with additional resistance determinants. Phylogenetic analysis supported the classification of this gene as a novel allele, mcr-10.6. The persistence of a clonal lineage harboring mcr-10.6 throughout the treatment system indicates that conventional wastewater treatment may not effectively eliminate clinically relevant ARGs. These findings highlight treated effluent as a potential route for environmental dissemination of colistin resistance and reinforce the need for improved monitoring and mitigation strategies within a One Health framework. Full article

Developing efficient and sustainable catalysts for advanced oxidation processes (AOPs) to remove endocrine-disrupting compounds remains a critical challenge. In this study, a defect-engineered MnFe₂O₄@SBC composite was synthesized by loading spinel MnFe₂O₄ onto sewage sludge-derived biochar (SBC) prepared at different calcination temperatures, and applied for efficient periodate (PI) activation toward bisphenol A (BPA) degradation. The catalytic performance exhibited a volcano-type dependence on calcination temperature, with MnFe₂O₄@SBC-750 achieving the highest BPA removal efficiency (98.6% within 30 min). Structural characterization revealed that MnFe₂O₄@SBC-750 possessed an optimized carbon structure with a balance between defect sites and graphitized domains. Mechanistic investigations demonstrated that multiple reactive oxygen species, including ^•OH, O₂^•−, IO₃^• and ¹O₂, were involved in BPA degradation. LC-MS analysis identified key transformation intermediates and proposed degradation pathways, while toxicity assessment confirmed reduced ecological risks after treatment. Density functional theory (DFT) calculations indicated that MnFe₂O₄@SBC significantly enhanced PI adsorption and activation by promoting interfacial electron transfer and elongating the I-O bond in IO₄⁻. Notably, MnFe₂O₄@SBC-750 exhibited the strongest electron transfer capability, attributed to the optimal regulation of defect density and graphitization degree, which facilitated π-d electronic coupling at the MnFe₂O₄-SBC interface. Overall, this work elucidates the critical role of defect regulation in spinel biochar-based catalysts for oxidant activation and provides a sustainable strategy for converting sewage sludge into high-performance catalysts for water purification. Full article

The pollution of water, including salt and fresh water, has become an emergency problem. Pollutants come from different sources and have various characteristics, starting from industry and fertilizers used in agriculture, sewage related to human living, and other sources. Diverse sources of pollution require a comprehensive approach to water purification. One possible approach may be the use of appropriate sorbents. Currently, one of the most promising materials used is zeolites. This is because they can come from various sources, including waste raw materials such as fly ash, and, therefore, allow for the use of a circular economy approach. Moreover, these materials can be modified, which enables their selective use for selected types of pollutants. Eventually, these materials become economically viable options. The main aim of this article is to present and analyze possible solutions to water pollution based on zeolite materials. For this purpose, a critical literature review was prepared. The review reveals that zeolites perform particularly well in ion-exchange-driven removal of inorganic contaminants, while their effectiveness for organic micropollutants under realistic conditions is often limited. The identified trade-offs between removal efficiency, regeneration stability, and scalability indicate that zeolites are best applied as function-specific rather than universal sorbents. From a sustainability perspective, this targeted applicability is supported by advantages, such as low material cost, long service life, and the possibility of using naturally occurring or waste-derived precursors, which, together, enable resource-efficient water treatment processes, reduced reliance on energy-intensive technologies, and the valorization of industrial byproducts within circular economy frameworks. Full article

The challenge of attaining energy–efficient nitrogen removal at low carbon–to–nitrogen (C/N) ratios is a fundamental issue in the sustainable management of municipal wastewater treatment plants (WWTPs). This study investigates a pilot–scale Anaerobic–Swing–Anoxic–Oxic (ASAO) system coupled with an AvN (Ammonia versus NOx⁻–N)–based aeration control strategy. A systematic evaluation of the system’s performance, nitrogen removal mechanisms, and microbial communities under a 350–day long–term pilot–scale operation using real municipal sewage is presented. The results reveal that the AvN control strategy can optimize aeration intensity and enhance nitrogen removal efficiency. Even under low influent C/N conditions, the ASAO system maintained stable operation with low dissolved oxygen levels (0.5–1.5 mg L⁻¹), and the AvN control strategy effectively optimized aeration intensity and stabilized nitrogen conversion, achieving a total nitrogen (TN) removal rate of 83% and an average effluent TN concentration of 4.9 ± 2.6 mg L⁻¹. Mechanistic analysis indicated that AvN regulation could alleviate over–nitrification and enhance intracellular carbon storage, thereby creating conditions that support the coordinated operation of multiple nitrogen removal routes, such as simultaneous nitrification–denitrification (SND), endogenous denitrification (EnD), and potentially anaerobic ammonium oxidation (anammox). These findings suggest that the AvN–controlled ASAO process offers a robust and scalable strategy for achieving high–efficiency nitrogen removal with reduced aeration demand, providing a promising technological pathway toward energy–neutral and sustainable municipal wastewater treatment. Full article

Urban lake ecosystems in rapidly growing cities face multiple, interlinked pressures. This article examines how these pressures are understood and addressed in research and practice by synthesising 413 academic, policy, and practitioner studies on lake degradation and restoration in the Bengaluru region, India. Using Content Configuration Analysis, we pursue four lines of inquiry: typifying dominant research approaches; mapping how major drivers—climate change, urbanisation, expanding consumption, and governance fragmentation—generate pressures; analysing sewage treatment plants (STPs) as responses that can themselves become new stressors; and comparing national restoration guidelines with locally developed strategies. Our analysis shows that lake problems are frequently framed as discrete technical issues, whereas degradation operates through recursive driver–pressure–response dynamics that cut across ecological, institutional, and social domains. The STP cases illustrate this mismatch, where mandated solutions can generate unintended pressures when institutional capability or ecological integration is weak. Comparisons between national guidelines and locally grounded practices reveal broad alignment in restoration principles but persistent gaps remain in implementation capacity, coordination, financing, and integration with land-use and urban resilience planning. Based on our analyses, we argue for reconceptualising urban lakes as complex socioecological systems rather than bounded technical units. Such a perspective supports restoration strategies that are nationally coherent yet locally attuned, strengthening ecological function, social equity, and urban resilience. More broadly, the findings contribute to debates on the restoration and governance of urban water bodies by demonstrating how national policy frameworks can be reinforced through locally grounded socioecological knowledge. Full article

Sewage sludge (SS) is a by-product of wastewater treatment processes (WWTPs) and is rich in organic matter and essential nutrients like nitrogen, phosphorus, and potassium, making it a potential fertilizer for agricultural use. However, its application is often limited due to the presence of pathogenic bacteria, viruses, metals, and organic contaminants that can accumulate in soils and crops, raising concerns about food safety. Sewage sludge is additionally challenging to handle due to its high moisture content, low density, and odor emission. To mitigate environmental risks and enhance its usability as a soil fertilizer, SS must be stabilized. Various techniques, including chemical, physical, and biological, can be used to stabilize SS. The addition of lime and composting has received particular attention among these techniques owing to the benefits they offer. Both methods effectively control and eliminate pathogens and reduce metal bioavailability, thus improving their agricultural utility. This review emphasizes the importance of using SS for agricultural purposes, placing particular focus on the procedures of composting and liming to stabilize and enhance the quality of SS, hence promoting its safety. Full article

Sewage sludge management poses major environmental challenges due to increasing production and concerns about contaminants and microbial risks. Vermicomposting offers a sustainable biological treatment, yet the extent to which different earthworm species shape microbial outcomes remains poorly understood. Here, we examined how gut transit by three epigeic (Eisenia andrei, E. fetida, and Dendrobaena hortensis) and two anecic (Lumbricus friendi and L. terrestris) earthworm species alters bacterial and fungal communities in fresh sewage sludge. Using 16S rRNA and ITS amplicon sequencing combined with multivariate, differential-abundance, and functional prediction analyses, we compared sludge and earthworm cast bacteriomes and mycobiomes. Earthworm gut transit caused pronounced species-specific restructuring of bacterial and fungal community composition, diversity, and functional profiles, with clear separation between sludge and cast communities. Functional analyses indicated coordinated shifts in bacterial metabolic potential and fungal trophic modes consistent with enhanced biosynthetic and decomposer functions. Pathogen profiles were reshaped in a host-dependent manner, with low overall abundances and selective changes rather than uniform suppression. These findings demonstrate that vermicomposting outcomes depend strongly on earthworm species and microbial kingdom, highlighting the importance of earthworm lifestyle diversity when evaluating the ecological safety and agronomic potential of sludge-derived amendments. Full article

This study assessed the impact of pandemic-related changes in treated wastewater on surface water quality and ecological status of the Raba River within the Natura 2000 site. Particular attention to the reliability of the Kasinka Mała wastewater treatment plant operating in this protected area during the two study periods—pre-pandemic (PP) and COVID-19 (CP)—was given. For this purpose, current standard monitoring methods (ecological status of a small flysch stream, existing and potential threats to the Natura 2000 site) and extended monitoring methods (river’s utility values, technological reliability of the treatment plant operating with SBR technology, reliability rating of the river as a sewage receiver) were used. The results indicated that biodegradable carbon compounds (as dissolved and suspended forms) and ammonium nitrogen were the dominant factors determining water quality. Their presence reduced the Raba River’s utility value—determined by what is required of surface water treatment—by at least one class. During the CP, the reliability analysis showed that the river remained in a reduced class for 145 days due to elevated BOD₅ and nearly one-third of the year due to elevated TSS levels. For approximately half of the year, ammonium nitrogen concentrations exceeded the threshold of 1.8 mg·dm⁻³, thereby further reducing the class of water quality. Technological reliability of the WWTP during PP for BOD₅, COD, TSS, NH₄⁺–N, and PO₄⁻³–P was 43%, 100%, 30%, 86%, and 100%, respectively. This means that permitted values of COD and PO₄⁻³–P were maintained. The exceedances of limits concerned BOD₅ (25 mg O₂·dm⁻³ for 208 days), TSS (35 mg·dm⁻³ for 256 days), and NH₄⁺–N (15 mg·dm⁻³ for 51 days). During CP, the technological reliability of the WWTP decreased rapidly for the following pollutants to 5%, 18%, 18%, 30%, and 89%, respectively. This means that permissible concentrations of BOD₅ (25 mg O₂·dm⁻³ for 347 days), COD (125 mg O₂·dm⁻³ for 241 days), TSS (35 mg·dm⁻³ for 299 days), NH₄⁺–N (15 mg·dm⁻³ for 256 days), and PO₄⁻³–P (2 mg·dm⁻³ for 40 days) were exceeded. A two-year monitoring campaign has shown that small flysch rivers receiving treated wastewater may experience prolonged changes in water quality under conditions of increased anthropopressure. Effective ecosystem protection should, therefore, include extended monitoring and stricter management of BOD₅, TSS, and NH₄⁺–N in SBR systems in protected areas. Full article

Antimicrobial resistance (AMR) has become a major concern in the treatment of bacterial infections, and bacteriophage therapy has emerged as a promising alternative to antibiotics. Bacteriophages are highly specific to their bacterial hosts; hence, isolating phages indigenous to a specific region offers a significant advantage against various pathogen strains. We have isolated a cocktail of bacteriophages against pathogenic E. coli from sewage water at a primary healthcare centre. Characterisation of the isolated phages demonstrated their stability across a broad pH and temperature range, strong lytic activity, and effective biofilm degradation, with no cross-reactivity with Staphylococcus aureus (S. aureus). Genomic analysis and phylogenetic studies indicated that the largest phage (by genome size) in the cocktail belongs to the genus Vequintavirus (myoviruses, rV5-like phages), and its genome sequence has been deposited in NCBI (Accession ID: PX741096). The phage genome was linear, with headful (PAC) packaging, encoded lysis proteins, and lacked antibiotic-resistant or major lysogeny-associated genes, collectively suggesting a lytic lifestyle. These findings emphasize the therapeutic potential of rV5-like phages and underscore the critical need to establish phage banks in India to improve disease management. Full article

To address the bottleneck of poor biological nitrogen removal efficiency caused by the extremely low carbon-to-nitrogen (C/N) ratio of domestic sewage in alpine plateau regions, this study used Hordeum vulgare var. coeleste L., a characteristic crop endemic to the Qinghai–Tibet Plateau, as raw material and adopted pretreated highland barley straw as an external carbon source. Three parallel experiments were carried out using the anaerobic–aerobic–anoxic sequencing batch reactor (AOA-SBR) process to investigate the nitrogen removal performance and functional succession of the microbial community in the AOA-SBR system under three C/N ratio ranges: 5~7, 7~9, and 9~11. The results showed that the addition of an external carbon source significantly improved nitrogen removal efficiency. The optimal C/N ratio range for nitrogen removal in this study was determined to be 7~9. A weakly alkaline environment was conducive to denitrification. The fermentation broth prepared by alkali pretreatment contained a large amount of readily biodegradable organic matter with low toxicity, and achieved excellent nitrogen removal performance, helping to realize cost reduction and efficiency improvement in wastewater treatment. At the optimal C/N ratio of 7~9, the average removal efficiencies of ammonia nitrogen (NH₄⁺-N) and total nitrogen (TN) reached 94.46% and 61.32%, respectively, which were significantly improved compared with the blank control group without external carbon addition. During the experimental period, no obvious changes were observed in microbial abundance at the phylum level, whereas the community structure at the genus level responded significantly to the addition of a straw carbon source. Among them, genera with specific degradation capabilities for straw hydrolysates, such as norank_f__Chitinophagaceae and unclassified_f__Comamonadaceae, were highly sensitive to variations in the C/N ratio. These genera could partially replace the nitrification and denitrification functions of other microorganisms and played a key role in the nitrogen removal process. In contrast, Thauera, a typical conventional heterotrophic denitrifier, showed no significant response to changes in the C/N ratio, indicating that the straw-based external carbon source mainly affected microbial genera with specific hydrolysate-degrading functions. Full article

Microsieving-based advanced primary treatment (APT) has attracted increasing attention as an approach for restructuring carbon and energy flows within wastewater treatment plants (WWTPs). Unlike previous work that has often addressed individual microsieving technologies or specific recovery routes separately, this review provides a unified framework for comparing drum screens (DSs)/drum filters (DFs), cloth disc filters (CDFs), and rotating belt filters (RBFs) with conventional primary sedimentation (PST) in terms of separation mechanisms and pollutant capture. On this basis, it further discusses recent progress in energy and resource recovery from primary screenings, together with their relevance to energy demand reduction and carbon redistribution in WWTPs. Current limitations arise at two levels. Microsieving technologies remain constrained by mesh fouling and limited control over selective pollutant capture, while plant-wide evidence remains insufficient, particularly regarding techno-economic assessment of recovered products and life cycle assessment of full plant performance after replacing primary sedimentation. Future work should therefore focus on targeted process optimization and plant-wide evaluation of economic and environmental feasibility. Full article

Globally, the rise in MDR P. aeruginosa infections poses a serious threat to public health, as these strains frequently exhibit extensive resistance to conventional antibiotics, prompting interest in bacteriophages as alternative treatments. In this study, we isolated and characterized a lytic P. aeruginosa phage, vB_Pae_YuaWU01, from hospital sewage in southern Thailand. Morphological analysis revealed Siphovirus-like characteristics. The phage demonstrated efficient host adsorption, with approximately 85.9% of particles attached within 15 min, and exhibited a latent period of 50 min with a burst size of 17.2 PFU/cell. It showed strong lytic activity, consistently suppressing bacterial growth without no regrowth observed over 72 h. Notably, the phage significantly inhibited biofilm formation by up to 59.9% and reduced pre-established biofilms by 39.78% at the highest tested concentration (10⁹ PFU/mL). Genome analysis revealed a 61,824 bp double-stranded DNA genome with 64.48% GC content and 88 predicted genes. Bioinformatic analysis suggests that the genome is organized into structural, replication, and lysis modules. Importantly, no toxin, antimicrobial resistance, lysogeny, or tRNA genes were identified, suggesting a favorable safety profile. The phage was classified within the genus Yuavirus, showing 97.4% genomic similarity to Sphaerotilus phage SN1, which infects a different host strain. The findings highlight its potential as a genetically safe therapeutic agent; however, its limited host range indicates that it may be best positioned as a strategic component of phage cocktails or as a synergistic partner with antibiotics to maximize therapeutic efficacy. Full article

Deammonification, which is based on partial nitritation and anammox (PN/A), is a well-established sidestream treatment for nitrogen removal. However, transferring deammonification to mainstream wastewater treatment remains challenging due to low temperatures, the need to retain slow-growing anammox bacteria (AnAOB), and their competition for nitrite with nitrite-oxidizing bacteria (NOB) and heterotrophic denitrifiers. This work investigates cubic polyurethane foam carriers to promote growth and retention of AnAOB. A moving bed biofilm reactor (MBBR) and an integrated fixed-film activated sludge (IFAS) reactor were compared over a three-year experimental period at lab-scale. The feasibility of the biofilm carriers for deammonification was first evaluated under sidestream conditions, followed by a stepwise transition to mainstream operational conditions. The impact of operational parameters, including dissolved oxygen concentration, pH value, and aeration strategy, was evaluated with respect to the activity of aerobic ammonium-oxidizing bacteria (AOB), NOB, and AnAOB, as well as nitrogen removal rates. Deammonification reached nitrogen removal rates of 0.04–0.12 kg N m⁻³ d⁻¹ (IFAS reactor) and 0.02–0.28 kg N m⁻³ d⁻¹ (MBBR) at subphases with reactor bulk concentrations above 60 mg NH₄-N L⁻¹. Highest nitrogen removal degrees of 77 ± 6% (IFAS) and 76 ± 5% (MBBR) were achieved at reactor bulk concentrations of 96 mg NH₄ L⁻¹ and 97 mg NH₄ L⁻¹, respectively. Lower concentrations triggered NOB activity in both reactors, leading to an increase in nitrate concentration up to 22 mg NO₃-N L⁻¹. AOB and AnAOB activities were on average 6-fold higher on the carriers compared to suspended biomass throughout all experimental phases, demonstrating the feasibility of using cubic polyurethane foam carriers for deammonification. This was also confirmed by fluorescence in-situ hybridization (FISH) measurements. Median nitrogen removal rates over all experimental phases of 0.07 kg N m⁻³ d⁻¹ for the IFAS reactor and 0.05 kg N m⁻³ d⁻¹ for the MBBR were achieved, which are comparable to conventional activated sludge systems performing nitrogen removal via nitrification–denitrification. While at lower nitrogen concentrations, the IFAS reactor yielded superior nitrogen removal rates, peak nitrogen removal rates of 0.28 kg N m⁻³ d⁻¹ were measured in the MBBR configuration. However, controlling NOB activity at lower temperatures and concentrations remains a challenge in MBBR and IFAS configurations. In our study, in the IFAS reactor NOB activities were visible on fewer days than in MBBR. At mainstream-like conditions, higher nitrogen removal rates of IFAS (0.09–0.12 kg N m⁻³ d⁻¹) were achieved compared to the MBBR (0.06–0.09 kg N m⁻³ d⁻¹). This demonstrates the advantage of the IFAS reactor in treating mainstream wastewater via deammonification. As an autotrophic nitrogen removal process, the implementation of deammonification in the mainstream of municipal wastewater treatment plants enables enhanced recovery of biogas from sewage organic matter. The latter would otherwise be consumed during the conventional nitrification-denitrification pathway. Consequently, the overall energy balance for wastewater treatment can be improved, contributing to a more environmentally sustainable process. Full article

This study systematically compared the performance of different composite magnetic materials in enhancing activated sludge treatment of municipal wastewater. A sequencing batch reactor (SBR) process was used as the model system. Four different composite magnetic materials were examined: Fe₃O₄ composite activated carbon, Fe₃O₄ composite diatomite, Fe₃O₄ composite composite kaolin, and Fe₃O₄ composite composite fly ash. Their performance in enhancing activated sludge treatment of municipal wastewater was evaluated in terms of pollutant removal, sludge physicochemical properties, and molecular biology analysis. Furthermore, the two best-performing composite magnetic materials were further investigated at different dosages to examine their pollutant removal performance and mechanisms. Furthermore, the two best-performing composite magnetic materials were further investigated at different dosages to examine their pollutant removal performance and mechanisms. The results showed that, compared with the control system (without material addition), the addition of four composite magnetic materials improved the average removal efficiencies as follows: for the Fe₃O₄ composite activated carbon, Fe₃O₄ composite diatomite, Fe₃O₄ composite kaolin, and Fe₃O₄ composite composite fly ash systems, COD removal increased by 2.55%, 2.77%, 1.67%, and 4.10%, respectively; TN removal increased by 1.71%, 3.33%, 4.82%, and 0.82%, respectively; and TP removal increased by 4.96%, 7.02%, 6.01%, and 5.76%, respectively. In the Fe₃O₄ composite diatomite system, the highest average removal efficiencies of COD, TN, and NH₄⁺-N were achieved at a dosage of 50 mg/L, whereas the highest average TP removal efficiency was achieved at a dosage of 200 mg/L. In the Fe₃O₄ composite kaolin system, the highest average removal efficiencies of COD, TP, and NH₄⁺-N were achieved at a dosage of 50 mg/L, while the highest average TN removal efficiency was achieved at a dosage of 200 mg/L. High-throughput sequencing indicated that the highest activity of denitrifying genera was observed in the Fe₃O₄ composite diatomite system at a dosage of 50 mg/L and in the Fe₃O₄ composite kaolin at a dosage of 200 mg/L, respectively. The addition of composite magnetic materials enhances the efficiency of municipal wastewater biological treatment. These findings provide theoretical and technical guidance for the selection of magnetic composite materials in municipal wastewater treatment. Full article

The new-generation aeration blower, which uses a high-speed permanent-magnet synchronous motor supported by elastic-foil thrust bearings, represents the future development trend of high-end sewage treatment turbomachinery. An axial load tester was designed for the elastic-foil thrust bearings in this study. Firstly, the relationship between the axial load and the elastic-foil thrust bearing parameters was first established. An axial load tester was designed. Secondly, finite-element simulation and strain calibration of the axial load tester were performed to estimate the linear relationship between the strain and the axial load. Then, the time histories of axial load for the high-speed permanent-magnet synchronous motor were further obtained at a rotational speed of 15,000 rpm during the operation tests. Finally, the load spectrum was compiled by fitting the test data to a function. The results showed that the amplitude and frequency of the load spectrum obeyed an exponential decay function. It can be used for the life test of elastic-foil thrust bearings in the future. The method for obtaining the axial load in the direct-driven turbomachinery was proposed. The axial load tester proposed in the present study, based on operation tests, proves valuable for improving the performance of the high-speed permanent magnetic synchronous motor and the elastic-foil thrust bearing. Full article