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UNLABELLED: Wastewater treatment plants (WWTPs) are indispensable biotechnology facilities for modern cities and play an essential role in modern urban infrastructure by employing microorganisms to remove pollutants in wastewater, thus protecting public health and the environment. This study conducted a 13-month bacterial community survey of six full-scale WWTPs in Hong Kong with samples of influent, activated sludge (AS), and effluent to explore their synchronism and asynchronism of bacterial community. Besides, we compared AS results of six Hong Kong WWTPs with data from 1,186 AS amplicon data in 269 global WWTPs and a 9-year metagenomic sequencing survey of a Hong Kong WWTP. Our results showed the compositions of bacterial communities varied and the bacterial community structure of AS had obvious differences across Hong Kong WWTPs. The co-occurrence analysis identified 40 pairs of relationships that existed among Hong Kong WWTPs to show solid associations between two species and stochastic processes took large proportions for the bacterial community assembly of six WWTPs. The abundance and distribution of the functional bacteria in worldwide and Hong Kong WWTPs were examined and compared, and we found that ammonia-oxidizing bacteria had more diversity than nitrite-oxidizing bacteria. Besides, Hong Kong WWTPs could make great contributions to the genome mining of microbial dark matter in the global wanted list. Operational parameters had important effects on OTUs abundance, such as the temperature to the genera of Tetrasphaera, Gordonia and Nitrospira. All these results obtained from this study can deepen our understanding of the microbial ecology in WWTPs and provide foundations for further studies. IMPORTANCE: Wastewater treatment plants (WWTPs) are an indispensable component of modern cities, as they can remove pollutants in wastewater to prevent anthropogenic activities. Activated sludge (AS) is a fundamental wastewater treatment process and it harbors a highly complex microbial community that forms the main components and contains functional groups. Unveiling who is there is a long-term goal of the research on AS microbiology. High-throughput sequencing provides insights into the inventory diversity of microbial communities to an unprecedented level of detail. At present, the analysis of communities in WWTPs usually comes from a specific WWTP and lacks comparisons and verification among different WWTPs. The wide-scale and long-term sampling project and research in this study could help us evaluate the AS community more accurately to find the similarities and different results for different WWTPs in Hong Kong and other regions of the world.

Wastewater treatment plants (WWTPs) at pig farms are significant environmental reservoirs of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). In particular, contamination by multidrug-resistant Alcaligenes faecalis (MDR-AF) poses an increasingly severe threat to human health. However, no safe and effective method is currently available to hinder its dissemination in the environment. In this study, two hitherto unreported bacteriophages were screened. In addition, qPCR experiments demonstrated that applying these bacteriophage preparations to wastewater significantly eradicates MDR-AF and reduces ARGs by 0.7–2.5 orders of magnitude (P < 0.05), thereby substantially diminishing the risk of antibiotic resistance transmission. Furthermore, various characterizations, bacteriophage genomic analysis, and microbial community analysis indicated that these bacteriophage preparations possess safety, specificity, and high resilience, rendering them an efficient and eco-friendly biological control measure. [Display omitted] • Bacteriophages CASP1 & CASP2 isolated to target multidrug-resistant (MDR) bacteria. • CASP1 & CASP2 reduce MRD Alcaligenes faecalis & antibiotic resistance genes (ARGs). • Monotypes cause more inactivation than mixed phages owing to competitive inhibition. • Mixed phages decrease ARGs more effectively than monotypic phages. • Both bacteriophages are confirmed as environmentally friendly, safe, and efficient. [ABSTRACT FROM AUTHOR]

The emerging pollutant paracetamol (APAP) is one of the most prescribed drugs worldwide. In addition, APAP and its main metabolites, namely, 4-aminophenol (4-AP), hydroquinone (H2Q), benzoquinone (BQ), and 2,5-dihydroxy-1,4-benzoquinone (2,5-OH-BQ), among others, are frequently detected in wastewater treatment plants (WWTPs) influents, effluents, and the environment. Thus, continuous release into the environment, especially aquatic environments, is a source of general concern. Six APAP-degrading bacterial strains were isolated from two mine samples from the Iberian Pyrite Belt (Lousal and Poderosa mines). Mycolicibacterium aubagnense HPB1.1, which was isolated using enrichment cultures from the Poderosa mine sample in the presence of H2Q as the sole carbon source, also showed APAP biodegrading capabilities. Pure cultures of this strain degraded 34.3 mg L−1 of APAP in 5 days and 9.4 mg L−1 of H2Q in 4 days. Interestingly, BQ and 2,5-OH-BQ were detected as metabolites resulting from H2Q abiotic degradation, but these compounds were removed in the strain's cultures. Furthermore, M. aubagnense HPB1.1 whole-genome was sequenced, and its encoded proteins were aligned with enzymes of APAP-degrading bacteria recovered from databases and literature aiming to identify candidate catabolic genes. Putative amidases, deaminases, hydroxylases, and dioxygenases, responsible for the degradation of APAP by the HPB1.1 strain, were identified by similarity, corroborating its ability to transform APAP and its intermediate metabolite H2Q into less toxic metabolic compounds due to their capacity to break the aromatic ring of these molecules. [ABSTRACT FROM AUTHOR]

Introduction: The presence of pharmaceuticals and personal care products in environmental matrices is considered one of the major scientific concerns. Most of these substances are disposed of unchanged through wastewater treatment plants and sewage systems. Consequently, they are continuously introduced into the water systems and progressively contaminate surface, ground and drinking water. During the COVID-19 pandemic, a large number of emerging contaminants including parabens were released to the environment through various routes. In this study, the occurrence of parabens (methylparaben (MePB), ethylparaben (EtPB), propylparaben (PrPB), and butylparaben (BuPB) was investigated in wastewater samples from various wastewater treatment plants (WWTPs) and the receiving surface waters in KwaZulu Natal and Gauteng Provinces (South Africa). Methods: The samples were collected between October 2020 and December 2021, covering the 2nd, 3rd and 4th waves of the COVID-19 pandemic. A solid phase extraction protocol with high-performance liquid chromatography was used to extract and enrich parabens before analysis. Results and Discussion: Methylparaben (2.02-84.7 μg/L), EtPB (<0.24-24.8 μg/L), PrPB (<0.26-55.1 μg/L), and BuPB (<0.27-17.3 μg/L) were quantified in wastewater influent collected WWTPs of KwaZulu Natal Province. While <0.19-5.43 μg/L, <0.16-5.63 μg/L, <0.17-6.89 μg/L, and <0.19-5.32 μg/L for MePB, EtPB, PrPB, and BuPB, respectively, were quantified in effluent wastewater from the same province. The concentrations of MePB, EtPB, PrPB, and BuPB in influent wastewater from Gauteng Province were 2.58-123 μg/L, <0.24-33.6 μg/L, 3.77-73.4 μg/L and <0.27-85.8 μg/L, respectively. In effluent wastewater, concentrations ranging from 0.24-17.76 μg/L (MePB), <0.16-4.88 μg/L (EtPB), 0.69-12.5 μg/L (PrPB), and <0.19-4.726 μg/L (BuPB) were quantified. During the 4th wave, the concentrations of parabens in surface water were lower compared to the second and third waves of the pandemic. In general, the paraben residues in the surface of KwaZulu Natal Province (<0.08-16.4 μg/L) were higher than those in Gauteng Province (0.08-3.14 µg/L). Methylparaben and propylparaben were dominant in all investigated samples (wastewater and surface water), followed by ethylparaben. The ecotoxicological risk assessment was carried out for aquatic biota, which was estimated in terms of risk quotients (RQs). RQs for the target compounds in river water indicated that MePB and EtPB pose low risk, whereas PrPB and BuPB pose low to medium risk to aquatic organisms. [ABSTRACT FROM AUTHOR]

The rare earth elements and yttrium (REY) are critical resources increasingly released into the environment due to their pivotal role for an ever-growing number of high-tech products and processes. Fjords, worldwide and particularly in Norway, are not only of high importance for biodiversity but they also have great economic value. Knowledge on the distribution of REY in Norwegian coastal and riverine waters is, however, surprisingly scarce. We here report REY data for water samples from depth profiles from ten stations in the Trondheimfjord, one of Norway's largest fjords, several Norwegian rivers, and two wastewater treatment plants in Trondheim. Our results show that water from different locations in the Trondheimfjord yield similar REY concentrations that correlate well with dissolved organic carbon. The deepest sample at each station shows the lowest REY concentrations. The shale-normalised (SN) REY patterns of the fjord waters resemble those of North Atlantic seawater, but can be distinguished from open-ocean water by the smaller fractionation between light and middle REY (Pr SN /Tb SN ≥ 0.5). Stations in the vicinity of a river mouth show considerably higher REY concentrations at shallow depths. The respective REY SN patterns resemble the typically flat patterns of boreal rivers that are often rich in nanoparticles and colloids (NPCs). The REY SN patterns of the four rivers investigated (Nidelva, Orkla, Gaula, Stjørdalselva) show the features of the shallow(er) fjord water samples but have even higher REY concentrations. Ultrafiltration (< 1 kDa) data for the Nidelva corroborate that the typical "REY SN seawater signature" is in fact already present in freshwater where it is, however, usually hidden by the REY associated with NPCs. The local wastewater treatment plants release anthropogenic Gd (from contrast agents used in magnetic resonance imaging) into the Trondheimfjord, but this signal is immediately diluted and thus is not observed in the REY SN patterns of the fjord water. However, our results in general suggest that the slightly elevated Gd/Tb ratios observed in almost all fjord waters relative to North Atlantic marine water may rather be due to the presence of anthropogenic Gd in the southern North Sea and the Baltic Sea, corroborating that anthropogenic Gd can be applied as a sensitive far-field watermass tracer. [ABSTRACT FROM AUTHOR]

Antibiotics are intensively used in various sectors, such as human and animal husbandry, and in the current scenario, they are considered global contaminants in different environmental compartments. Constant antibiotic exposure leads to antimicrobial resistance in environmental microorganisms. However, the correlation between antibiotic exposure and resistance is still indistinct and unproven in environmental microbiota. The release of antibiotic-resistant bacteria from municipal wastewater into rivers poses a public health concern. This study aimed to explore the antibiotic resistance profiling of bacterial pathogens isolated from wastewater, sludge, water, and sediment samples of the Ganges River of three North Indian cities (Kanpur, Prayagraj and Varanasi) for summer and winter seasons. Antibiotic resistance profiles were done for 12 antibiotics through the disc diffusion method. PCR analysis of genomic and plasmid DNA, the prevalence of six Antibiotic Resistance Genes was evaluated in 103 bacterial isolates isolated from wastewater, sludge, river water and sediment samples of North Indian cities. This study gives insight into the role of wastewater treatment plants in the abundance and spread of antibiotic-resistant bacteria and genes through effluent in the receiving river environment. The consumption of antibiotics is very high in India, and Antibiotic Resistance Genes are mostly abundant in wastewater treatment plants and river water and sediment, which indicates that the river has the potential and probable reservoir of Antibiotic Resistance Genes. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) and antibiotic resistance genes (ARGs) in the environment are the major subject of concern across the globe as they jeopardize not only aquatic life but human health as well. MPs are potentially competent to adsorb various micropollutants (heavy metals), bacterial communities, and biofilm formation which comply with the requirement of efficient sorption of antibiotics and transfer of ARGs. MPs adsorb antibiotics through physicochemical interactions, leading to the formation of biofilm-enriched bacteria on the surfaces of MPs that further enhances the abundance of antibiotic resistance genes (ARGs) and facilitates their dispersal. Therefore, this review recapitulates the interactive forces responsible for antibiotics sorption on MPs and also the intricate relationship between MPs, antibiotics, and microbial hosts of ARGs. Furthermore, the role of the wastewater treatment plants (WWTPs), which serve as a formidable connecting link between MPs and the ecosystem, is discussed in relation to dissemination of antibiotics, ARGs, and antibiotic-resistant bacteria (ARB) to get a clear perception of the contribution of WWTPs in drawing together MPs with antibiotics, ARB, and ARGs. [ABSTRACT FROM AUTHOR]

AbstractThe bioremediation capacity of microalgae found in the wastewater channels in Irrigation District 03 (DR03) in Mexico was studied. The study evaluated the effect of pH, aeration, light intensity, and water source on the productivity, culture time, and composition of the microalgal biomass, predominantly made up of Chlorella vulgaris spp. Parameters such as Chemical Oxygen Demand (COD), total solids (TS), and turbidity were monitored to assess the efficiency and bioremediation capacity of the microbial consortium. The yield production of microalgal biomass was measured to evaluate the amount produced per unit volume of treated water. Two culture conditions were assessed: uncontrolled and controlled conditions of aeration and lighting. Under controlled culture conditions, a productivity of 0.031 g L−1 d−1 biomass with 17% lipidic fraction and 37.65% ash content was observed, along with a reduction in COD and turbidity by 57 and 85%, respectively. A biomass productivity of 0.024 g L−1 d−1 was obtained. [ABSTRACT FROM AUTHOR]

Sewage sludge can be used as an organic amendment as long as it is ensured that there is no risk of environmental contamination or risk to public health. In this study, sewage sludge from two wastewater treatment plants (WWTPs) subjected to two disinfection and stabilization treatments [40% (mass/mass), calcium oxide, and calcium hydroxide] and their respective untreated sewage sludge were used. Three control treatments were also added: conventional farmyard manure (FYM), a nitrogen (N) mineral fertilizer (ammonium nitrate 34.5% N) applied at a rate of 50 kg N ha−1 (N50) (the same rate of all organic amendments), and an unfertilized control (N0), totaling nine treatments. Lettuce (Lactuca sativa L.) was cultivated in pots for two growing cycles. The dry matter yield (DMY) was higher in the N50 treatment (13.5 and 10.6 g plant−1 in the first and second growing cycles, respectively), followed by sewage sludge (10.8 to 12.4 and 8.4 to 8.7 g plant−1), FYM (8.5 and 7.2 g plant−1), and the control (7.7 and 6.0 g plant−1). The DMY was related to the N provided by the different treatments, assessed by the N and nitrate concentrations in tissues, N uptake, and apparent N recovery (ANR). Sewage sludge, due to its high N concentration and low carbon (C)/N ratio, mineralized rapidly, providing a significant amount of N to plants, as well as other nutrients, such as phosphorus (P) and boron (B). FYM, with a higher C/N ratio, provided less N to plants, also due to the short duration of the lettuce growing cycle. Alkalized sewage sludge increased soil pH and calcium (Ca) availability for plants. Fertilizer treatments minimally influenced cationic micronutrients. Heavy metals in the initial sewage sludge were below the threshold values established in international legislation, and the levels in soil and lettuce tissues were generally not higher than those in other treatments. Both of the sewage sludges used in this study showed high fertilizing value and very reactive behavior, making nutrients available much more quickly than FYM. This information is relevant to consider in defining their agricultural use. [ABSTRACT FROM AUTHOR]

Waste water treatment plants (WWTPs) are considered as energy-intensive industries. A comprehensive assessment of energy efficiency in sewage treatment reveals issues of energy waste, offers insights into the energy consumption structure, fosters optimization of energy management, and enhances overall energy utilization. However, the mathematical modeling for energy efficiency evaluation becomes challenging due to the ambiguity and uncertainty of the parameters regarding energy consumption and various indicators. In this paper, the newly constructed evaluation method was used to quantify the energy efficiency. This method employs dimensional reduction, projecting the numerical values of unit energy consumption for various pollutants onto a lowerdimensional space, and then computing the projected eigenvalues. Larger eigenvalues indicate higher energy efficiency. Based on the evaluation results, the back propagation (BP) neural network is used to simulate the sewage treatment process. The results demonstrated that when the inflow load is small and the concentration of pollutants is high, the energy efficiency of sewage treatment plants performs well. When the inflow load is high and the concentration of pollutants is low, the energy efficiency of sewage treatment plants is poor. Meanwhile, the energy consumption could be decreased by 11.61 %, 14 %, and 15.26 % respectively in different scenarios. [ABSTRACT FROM AUTHOR]

Abstract The emerging pollutant paracetamol (APAP) is one of the most prescribed drugs worldwide. In addition, APAP and its main metabolites, namely, 4-aminophenol (4-AP), hydroquinone (H2Q), benzoquinone (BQ), and 2,5-dihydroxy-1,4-benzoquinone (2,5-OH-BQ), among others, are frequently detected in wastewater treatment plants (WWTPs) influents, effluents, and the environment. Thus, continuous release into the environment, especially aquatic environments, is a source of general concern. Six APAP-degrading bacterial strains were isolated from two mine samples from the Iberian Pyrite Belt (Lousal and Poderosa mines). Mycolicibacterium aubagnense HPB1.1, which was isolated using enrichment cultures from the Poderosa mine sample in the presence of H2Q as the sole carbon source, also showed APAP biodegrading capabilities. Pure cultures of this strain degraded 34.3 mg L−1 of APAP in 5 days and 9.4 mg L−1 of H2Q in 4 days. Interestingly, BQ and 2,5-OH-BQ were detected as metabolites resulting from H2Q abiotic degradation, but these compounds were removed in the strain’s cultures. Furthermore, M. aubagnense HPB1.1 whole-genome was sequenced, and its encoded proteins were aligned with enzymes of APAP-degrading bacteria recovered from databases and literature aiming to identify candidate catabolic genes. Putative amidases, deaminases, hydroxylases, and dioxygenases, responsible for the degradation of APAP by the HPB1.1 strain, were identified by similarity, corroborating its ability to transform APAP and its intermediate metabolite H2Q into less toxic metabolic compounds due to their capacity to break the aromatic ring of these molecules.

Despite having several economic and environmental benefits of locating suitable sites for wastewater treatment plants, only a few studies have been reported in the literature. The present study implemented a fuzzy-analytic hierarchy process (fuzzy-AHP) method followed by the multi-criteria decision analysis for identification of suitable locations for wastewater treatment plants. Also, the study incorporated additional parameters such as slope and relative elevation to reduce environmental hazards and to increase economic benefits of locating wastewater treatment plants. The findings of the study revealed that 2.05% (42.68 km2) of the total study area is suitable for the establishment of environmentally and economically suitable wastewater treatment plants in each zone of the study area. It was assumed that half of wastewater will be treated in the East zone and the other half will be treated in the West zone. A minimum area of 30 ha was considered to treat half of the wastewater generated and based on this, 10 suitable sites were identified with five sites located in each zone. The approach of this study will help public health engineers and other stakeholders to identify environmentally and economically suitable locations for wastewater treatment plants in the study area and other similar areas globally. HIGHLIGHTS A fuzzy-AHP-MCDA approach was used for locating wastewater treatment plants (WTPs).; The study identified economically and environmentally suitable 10 locations for WTPs.; This study reduced the subjectivity in ranking the parameters for siting WTPs.; The study will help the readers for identifying best locations for WTPs.;

Plastic pollution is an emergent global issue in freshwater and marine ecosystems. Microplastics enter waterways from a variety of sources, although the relative importance of point and nonpoint sources for a given watershed is not well understood. To determine whether medium-sized wastewater treatment plants are significant sources of microplastics to rivers draining into Lake Erie, we measured microplastic loads up- and downstream of two wastewater treatment plants in southeastern Michigan State (USA). We detected a significant increase in the microplastic load downstream from the wastewater treatment plant discharging into the Lower Rouge River, but not downstream from the one discharging into the Huron River. However, the background microplastic load was tenfold higher in the Huron River compared to the Lower Rouge River, likely obscuring our ability to detect the wastewater treatment plant as a point source. We found a positive relationship between river discharge and microplastic load in the Huron River, which drains a larger watershed area at the effluent discharge point than the Lower Rouge site, suggesting that watershed sources may be more important over larger spatial scales. We also performed experiments to test the effects of plastic on stream biofilm function to better understand how plastic pollution alters stream metabolism. Biofilms grown on high-density polyethylene and polypropylene had significantly lower metabolic diversity and metabolic response, respectively. Overall, our findings indicate that attention should be directed to both point and nonpoint sources to reduce microplastic pollution and that plastics may negatively affect the function of stream biofilm communities. [ABSTRACT FROM AUTHOR]

The use of digital twins is a rapidly emerging field for improved real-time control (RTC) and decision support for the operation of collection systems and water resource recovery facilities (WRRFs). Digital twins for collection systems can help minimize the impacts of flow variation due to extreme weather events, attenuate flows to the WRRF, and reduce sewer overflows and the associated effects. Similarly, digital twins for WRRFs can help improve process, energy, and cost efficiency, fully utilise plant volumes, reduce carbon footprint, and support operator training. The current study provides an overview of two digital twin applications for collection systems (Future City Flow) and WRRFs (TwinPlant) and presents a first example of digital twin integration for proactive collection system-WRRF operation under wet-weather conditions. Current applications of the integrated digital twin are described, including (i) proactive implementation of wet-weather operation mode in WRRF based on inflow forecast and (ii) evaluation of the impacts of RTC in collection systems on WRRF performance. Other potential application examples are described together with the challenges related to the use of this solution. Overall, this new approach has a wide potential to support the cooperation within water utilities towards the adoption of integrated wastewater management. HIGHLIGHTS Digital twins can provide a sound base for controlling catchments and water resource recovery facilities.; High-quality online data from the twinned facilities is a key for reliable digital twins.; Digital twins must be robust to gain operator trust.; Connected digital twins provide a basis for system-wide optimization.; Helps to move from siloed to integrated management.;

Wastewater treatment plants (WWTPs) are important and energy-intensive municipal infrastructures. High energy consumption and relatively low operating performance are major challenges from the perspective of carbon neutrality. However, water–energy nexus analysis and models for WWTPs have rarely been reported to date. In this study, a cloud-model-based energy consumption analysis (CMECA) of a WWTP was conducted to explore the relationship between influent and energy consumption by clustering its influent’s parameters. The principal component analysis (PCA) and K-means clustering were applied to classify the influent condition using water quality and volume data. The energy consumption of the WWTP is divided into five standard evaluation levels, and its cloud digital characteristics (CDCs) were extracted according to bilateral constraints and golden ratio methods. Our results showed that the energy consumption distribution gradually dispersed and deviated from the Gaussian distribution with decreased water concentration and quantity. The days with high energy efficiency were extracted via the clustering method from the influent category of excessive energy consumption, represented by a compact-type energy consumption distribution curve to identify the influent conditions that affect the steady distribution of energy consumption. The local WWTP has high energy consumption with 0.3613 kW·h·m−3 despite low influent concentration and volumes, across four consumption levels from low (I) to relatively high (IV), showing an unsatisfactory operation and management level. The average oxygenation capacity, internal reflux ratio, and external reflux ratio during high energy efficiency days recognized by further clustering were obtained (0.2924–0.3703 kg O2·m−3, 1.9576–2.4787, and 0.6603–0.8361, respectively), which could be used as a guide for the days with low energy efficiency. Consequently, this study offers a water–energy nexus analysis method to identify influent conditions with operational management anomalies and can be used as an empirical reference for the optimized operation of WWTPs.

In recent years, microplastics (MPs) have attracted worldwide attention as emerging pollutants, and wastewater treatment plants are among the environment's most important sources of MPs. This study aimed to summarize MPs effects on various aspects of sludge systems. The results showed that MPs inhibited substance transformation in sludge systems, with greater inhibition observed at higher concentrations and smaller MP particle sizes. Moreover, low concentrations of MPs promote extracellular polymeric substance (EPS) secretion, whereas high concentrations suppress EPS secretion, destroying the sludge structure. Granular sludge systems exhibit higher resistance to MPs than activated sludge systems owing to their layered structures. Micrometer-sized MPs primarily inhibit the dewatering performance of activated sludge through physical crushing, while nano-sized MPs primarily affect sludge dewatering through biological effects. However, for granular sludge system, micrometer-sized MPs were unable to penetrate the granular sludge interior, their affinity and aggregation capabilities enabled them to accumulate on the sludge surface. In contrast, nano-sized MPs can enter the interior of granular sludge and impair mass-transfer pathways, ultimately resulting in toxic effects. Furthermore, MPs induce various toxic effects in sludge systems (single and combined toxic effects). These toxic effects affect the expression of key enzymes and functional genes, leading to changes in microbial communities. Because of the layered structure of granular sludge systems, MPs may initially affect the microbial community structure outside the granules, with less impact on the internal microorganisms. However, the specific mechanism still needs to be explored. Finally, this study presents research questions and directions that require further investigation. [ABSTRACT FROM AUTHOR]

This study focuses on the occurrence status and removal efficiency of microplastics in wastewater treatment plant processes. Analysis of effluent and sludge samples from the Wulongkou and Shuangqiao wastewater treatment plants in Zhengzhou revealed an overall microplastic removal efficiency of 95.64% and 92.53%, respectively, indicating the effectiveness of wastewater treatment plants in reducing microplastic emissions. Microplastics primarily exist in forms such as fiber, fragment, floc, film, and grain. Fibers are predominant in the effluent of the Wulongkou plant, while fibers and films predominate in the effluent of the Shuangqiao plant. Moreover, microplastics are predominantly sized below 500 μm, with larger microplastics (2–5 mm) exhibiting higher removal efficiencies after secondary treatment. Analysis of microplastic types revealed that PE is the most common type in the effluent of the Wulongkou plant, while the Shuangqiao plant predominantly contains PE and PA66. The abundance of microplastics in sludge samples was found to be 6.4 ± 0.8 items/g and 11.3 ± 2.3 items/g, highlighting sludge as an important sink for microplastics. Surface analysis of microplastics revealed characteristics such as wrinkles and cracks, with energy-dispersive spectroscopy indicating significant adsorption of heavy metal elements such as Zn, Hg, and Pb onto microplastic surfaces in sludge. These findings underscore the importance of microplastic removal in wastewater treatment processes and provide scientific evidence for the control and management of microplastic pollution in the future. [ABSTRACT FROM AUTHOR]

The rapid increase in soil and water pollution is primarily attributed to anthropogenic factors, notably the mismanagement of post-consumer plastics on a global scale. This exploratory research design evaluated the effectiveness of natural hydrophobic cattail (Typha Latifolia) fibres (CFs) as bio-adsorbents of microplastic particles (MPPs) from wastewater. The study investigates how the composition of the adsorption environment affects the adsorption rate. Straightforward batch adsorption tests were conducted to evaluate the "spontaneous" sorption of MPPs onto CFs. Five MPP materials (PVC, PP, LDPE, HDPE, and Nylon 6) were evaluated. Industrial wastewater (PW) and Type II Distilled Water (DW) were employed as adsorption environments. The batch test results show that CFs are effective in removing five MPP materials from DW and PW. However, a higher removal percentage of MPPs was observed in PW, ranging from 89% to 100% for PVC, PP, LDPE, and HDPE, while the adsorption of Nylon 6 increased to 29.9%, a removal increase of 50%. These findings indicate that hydrophobic interactions drive the "spontaneous and instantaneous" adsorption process and that adjusting the adsorption environment can effectively enhance the MPP removal rate. This research highlights the significant role that bio-substrates can play in mitigating environmental pollution, serving as efficient, sustainable, non-toxic, biodegradable, low-cost, and reliable adsorbents for the removal of MPPs from wastewaters. [ABSTRACT FROM AUTHOR]

Background: Wastewater treatment plants (WWTPs) are crucial in the scope of European Commission circular economy implementation. However, bioaerosol production may be a hazard for occupational and public health. A scoping review regarding microbial contamination exposure assessment in WWTPs was performed. Methods: This study was performed through PRISMA methodology in PubMed, Scopus and Web of Science. Results: 28 papers were selected for data extraction. The WWTPs' most common sampled sites are the aeration tank (42.86%), sludge dewatering basin (21.43%) and grit chamber. Air sampling is the preferred sampling technique and culture-based methods were the most frequently employed assays. Staphylococcus sp. (21.43%), Bacillus sp. (7.14%), Clostridium sp. (3.57%), Escherichia sp. (7.14%) and Legionella sp. (3.57%) were the most isolated bacteria and Aspergillus sp. (17.86%), Cladosporium sp. (10.71%) and Alternaria sp. (10.71%) dominated the fungal presence. Conclusions: This study allowed the identification of the following needs: (a) common protocol from the field (sampling campaign) to the lab (assays to employ); (b) standardized contextual information to be retrieved allowing a proper risk control and management; (c) the selection of the most suitable microbial targets to serve as indicators of harmful microbial exposure. Filling these gaps with further studies will help to provide robust science to policy makers and stakeholders. [ABSTRACT FROM AUTHOR]

In response to China's policies on pollution control and carbon emission (CE) reductions, more stringent regulations have been implemented to evaluate CE in wastewater treatment facilities. In this study, we have analyzed CE from China's wastewater treatment plants (WWTPs) and influencing factor. Emission factor (EF) and operational data integrated methods (ODIM) were utilized to measure emissions, using data collected from 247 WWTPs over a 1-year period across seven regions in China. The average CE intensity was 0.45 kgCO2-eq/m3, affected by region, season, influent water quality, treatment processes, effluent discharge standards, and facilities. The scale effect was obvious only in the range of 2 × 105 m3/day. Underground WWTPs exhibited significantly higher CE compared to aboveground WWTPs. In summary, the assessment of CE in 247 actual WWTPs not only identifies emission reduction potential but also provides a scientific basis for formulating targeted emission reduction measures. [ABSTRACT FROM AUTHOR]

Sewage sludge should primarily find use in agriculture, reducing the quantity directed towards alternative disposal methods like incineration or deposition in municipal landfills. This study evaluated the agronomic value and the risk of soil and plant tissue contamination with heavy metals in sewage sludge obtained from two wastewater treatment plants (WWTP). The experiment was arranged as a 2 × 5 factorial (two sewage sludges, five sanitation treatments), involving lettuce cultivation in pots over two growing cycles. The two sewage sludges were sourced from the WWTPs of Gelfa and Viana do Castelo and underwent five sanitation and stabilization treatments (40% and 20% calcium oxide, 40% and 20% calcium hydroxide, and untreated sewage sludge). The Gelfa sewage sludge, characterized by a higher initial nitrogen (N) concentration, resulted in greater dry-matter yield (DMY) (12.4 and 8.6 g plant−1 for the first and second growing cycles, respectively) compared to that from Viana do Castelo (11.0 and 8.1 g plant−1), with N release likely being a major factor influencing crop productivity. The high N concentration and the low carbon (C)/N ratio of sewage sludge led to rapid mineralization of the organic substrate, which additionally led to a higher release of other important nutrients, such as phosphorus (P) and boron (B), making them available for plant uptake. Alkalizing treatments further stimulated sewage sludge mineralization, increasing soil pH and exchangeable calcium (Ca), thereby enhancing Ca availability for plants, and indicating a preference for use in acidic soils. Cationic micronutrients were minimally affected by the sewage sludge and their treatments. The concentrations of heavy metals in the sewage sludge, soils, and lettuce tissues were all below internationally established threshold limits. This study highlighted the high fertilizing value of these sewage sludges, supplying N, P, and B to plants, while demonstrating a low risk of environmental contamination with heavy metals. Nevertheless, the safe use of sewage sludge by farmers depends on monitoring other risks, such as toxic organic compounds, which were not evaluated in this study. [ABSTRACT FROM AUTHOR]

The concentration of viruses in sewage sludge is significantly higher (10–1000-fold) than that found in natural environments, posing a potential risk for human and animal health. However, the composition of these viruses and their role in the transfer of pathogenic factors, as well as their role in the carbon, nitrogen, and phosphorus cycles remain poorly understood. In this study, we employed a shotgun metagenomic approach to investigate the pathogenic bacteria and viral composition and function in two wastewater treatment plants located on a campus. Our analysis revealed the presence of 1334 amplicon sequence variants (ASVs) across six sludge samples, with 242 ASVs (41.22% of total reads) identified as pathogenic bacteria. Arcobacter was found to be the most dominant pathogen accounting for 6.79% of total reads. The virome analysis identified 613 viral genera with Aorunvirus being the most abundant genus at 41.85%. Approximately 0.66% of these viruses were associated with human and animal diseases. More than 60% of the virome consisted of lytic phages. Host prediction analysis revealed that the phages primarily infected Lactobacillus (37.11%), Streptococcus (21.11%), and Staphylococcus (7.11%). Furthermore, our investigation revealed an abundance of auxiliary metabolic genes (AMGs) involved in carbon, nitrogen, and phosphorus cycling within the virome. We also detected a total of 113 antibiotic resistance genes (ARGs), covering major classes of antibiotics across all samples analyzed. Additionally, our findings indicated the presence of virulence factors including the clpP gene accounting for approximately 4.78%, along with toxin genes such as the RecT gene representing approximately 73.48% of all detected virulence factors and toxin genes among all samples analyzed. This study expands our understanding regarding both pathogenic bacteria and viruses present within sewage sludge while providing valuable insights into their ecological functions. [ABSTRACT FROM AUTHOR]

Microplastics have multidimensional traits, as compared to other emerging contaminants, presenting a concern to terrestrial, aquatic life and humans through inhalation or ingestion. Hazardous chemicals adsorbed on microplastics could potentially be transferred to the environment or consumed by living organisms. We review the transformation of plastic waste in the environment, the origin and transportation of microplastics, the regulatory measures for plastic and microplastic pollution, and the fate of microplastics in wastewater treatment plants. Plastic debris is building up in the environment despite legislative attempts by many countries. Accumulated plastic waste from a range of sources breaks down into smaller fragments and microplastics through chemical, physiochemical and biodegradation mechanisms. This review also discusses personal protective equipment in relation to COVID-19 as a source of microplastics. Millions of microplastics are discharged into the environment through effluents and biosolids. Daily microplastic emissions to the environment from effluent range about 0.46 million to 140 billion. Previous studies had only explored the existence of microplastics in wastewater treatment plants, with limited visualization of how microplastics interact with the various treatment technologies used in wastewater treatment plants. [ABSTRACT FROM AUTHOR]

Monitoring and managing wastewater treatment plants (WWTPs) is crucial for environmental protection. The presection of the quality of treated water is essential for energy efficient operation. The current research presents a comprehensive comparison of machine learning models for water quality parameter prediction in WWTPs. Four machine learning models presented in MLP, GFFR, MLP-PCA, and RBF were employed in this study. The primary notion of this study is to apply the proposed models using two distinct modeling scenarios. The first scenario represents a straightforward approach by utilizing the inputs and outputs of WWTPs; meanwhile, the second scenario involves using multi-step modeling techniques, which incorporate intermediate outputs induced by primary and secondary settlers. The study also investigates the potential of the adopted models to handle high dimensional data as a result of the multi-step modeling since more data points and outputs are progressively integrated at each step. The results show that the GFFR model outperforms the other models across both scenarios, specifically in the second scenario in predicting conductivity (COND) by providing higher correlation accuracy (R = 0.893) and lower prediction deviations (NRMSE = 0.091 and NMAE = 0.071). However, all models across both scenarios struggle to predict the other water quality parameters, generating significantly lower prediction correlations and higher prediction deviations. Nonetheless, the innovative multi-step technique in scenario two has significantly boosted the prediction capacity of all models, with improvement ranging from 0.2 % to 157 % and an average of 60 %. The implementation of AI models has proven its ability to accomplish high accuracy for WQ parameter prediction, highlighting the impact of leveraging intermediate process data.

Introduction: The presence of pharmaceuticals and personal care products in environmental matrices is considered one of the major scientific concerns. Most of these substances are disposed of unchanged through wastewater treatment plants and sewage systems. Consequently, they are continuously introduced into the water systems and progressively contaminate surface, ground and drinking water. During the COVID-19 pandemic, a large number of emerging contaminants including parabens were released to the environment through various routes. In this study, the occurrence of parabens (methylparaben (MePB), ethylparaben (EtPB), propylparaben (PrPB), and butylparaben (BuPB) was investigated in wastewater samples from various wastewater treatment plants (WWTPs) and the receiving surface waters in KwaZulu Natal and Gauteng Provinces (South Africa).Methods: The samples were collected between October 2020 and December 2021, covering the 2nd, 3rd and 4th waves of the COVID-19 pandemic. A solid phase extraction protocol with high-performance liquid chromatography was used to extract and enrich parabens before analysis.Results and Discussion: Methylparaben (2.02–84.7 μg/L), EtPB (

In the context of global climate change, drought occurrence in streams of alpine origin is a recent phenomenon, whose impact is still poorly investigated. In this study, we adopted a three-disciplinary approach to investigate the response of an Alpine river (NW Italy) to severe drought conditions occurred in the year 2022. We hypothesised that the considerable loss in the water flow could exacerbate wastewater treatment plant (WWTP) discharge effects, lowering dilution capacity of the stream system and then increasing chemical/microbial pollution and altering benthic community characteristics. To assess river response to drought conditions of the considered year, the concentration of the main chemical variables, faecal indicator bacteria, pathogen presence and structural/functional organisation of benthic macroinvertebrates and diatom communities were measured monthly in the reaches located upstream and downstream of a WWTP (January–December 2022). Main environmental variables, such as flow velocity, water depth, and flow regime, were also considered. A multivariate analysis approach was then applied to emphasise correlations between selected variables and flow regime.Comparing upstream and downstream sections over the considered year, a common behaviour of chemical/microbiological parameters was observed, with generally higher concentrations of nutrients and bacterial indicators downstream of the local WWTP. Moreover, a positive correlation between water scarcity and nutrients/bacterial concentrations was revealed. The macroinvertebrate communities responded accordingly, both in terms of density and biological metric shift.Interestingly, differences between the two sections were strictly associated with hydrological conditions, with higher dissimilarities found in low-flow conditions. As the magnitude and duration of drought events are projected to increase in the years to come in different parts of Europe, this work can serve as a first building block and as a hint for future studies aimed at improving our knowledge about the consequences of these events that is pivotal for planning effective management strategies.

In Canada, every day, contaminants of emerging concern (CEC) are discharged from waste treatment facilities into freshwaters. CECs such as pharmaceutical active compounds (PhACs), personal care products (PCPs), per- and polyfluoroalkyl substances (PFAS), and microplastics are legally discharged from sewage treatment plants (STPs), water reclamation plants (WRPs), hospital wastewater treatment plants (HWWTPs), or other forms of wastewater treatment facilities (WWTFs). In 2006, the Government of Canada established the Chemicals Management Plan (CMP) to classify chemicals based on a risk-priority assessment, which ranked many CECs such as PhACs as being of low urgency, therefore permitting these substances to continue being released into the environment at unmonitored rates. The problem with ranking PhACs as a low priority is that CMP’s risk management assessment overlooks the long-term environmental and synergistic effects of PhAC accumulation, such as the long-term risk of antibiotic CEC accumulation in the spread of antibiotic resistance genes. The goal of this review is to specifically investigate antibiotic CEC accumulation and associated environmental risks to human and environmental health, as well as to determine whether appropriate legislative strategies are in place within Canada’s governance framework. In this research, secondary data on antibiotic CEC levels in Canadian and international wastewaters, their potential to promote antibiotic-resistant residues, associated environmental short- and long-term risks, and synergistic effects were all considered. Unlike similar past reviews, this review employed an interdisciplinary approach to propose new strategies from the perspectives of science, engineering, and law.

Domestic and industrial wastewater treatment plants (WWTPs) are facing formidable challenges in effectively eliminating emerging pollutants and conventional nutrients. In microbiome engineering, two approaches have been developed: a top-down method focusing on domesticating seed microbiomes into engineered ones, and a bottom-up strategy that synthesizes engineered microbiomes from microbial isolates. However, these approaches face substantial hurdles that limit their real-world applicability in wastewater treatment engineering. Addressing this gap, we propose the creation of a Global WWTP Microbiome-based Integrative Information Platform, inspired by the untapped microbiome and engineering data from WWTPs and advancements in artificial intelligence (AI). This open platform integrates microbiome and engineering information globally and utilizes AI-driven tools for identifying seed microbiomes for new plants, providing technical upgrades for existing facilities, and deploying microbiomes for accidental pollution remediation. Beyond its practical applications, this platform has significant scientific and social value, supporting multidisciplinary research, documenting microbial evolution, advancing Wastewater-Based Epidemiology, and enhancing global resource sharing. Overall, the platform is expected to enhance WWTPs’ performance in pollution control, safeguarding a harmonious and healthy future for human society and the natural environment.

BackgroundWastewater treatment plants (WWTPs) are one of the largest biotechnology applications in the world and are of critical importance to modern urban societies. An accurate evaluation of the microbial dark matter (MDM, microorganisms whose genomes remain uncharacterized) proportions in WWTPs is of great value, while there is no such research yet. This study conducted a global meta-analysis of MDM in WWTPs with 317,542 prokaryotic genomes from the Genome Taxonomy Database and proposed a "wanted list" for priority targets in further investigations of activated sludge.ResultsCompared with the Earth Microbiome Project data, WWTPs had relatively lower genome-sequenced proportions of prokaryotes than other ecosystems, such as the animal related environments. Analysis showed that the median proportions of the genome-sequenced cells and taxa (100% identity and 100% coverage in 16S rRNA gene region) in WWTPs reached 56.3% and 34.5% for activated sludge, 48.6% and 28.5% for aerobic biofilm, and 48.3% and 28.5% for anaerobic digestion sludge, respectively. This result meant MDM had high proportions in WWTPs. Besides, all of the samples were occupied by a few predominant taxa, and the majority of the sequenced genomes were from pure cultures. The global-scale "wanted list" for activated sludge contained four phyla that have few representatives and 71 operational taxonomic units with the majority of them having no genome or isolate yet. Finally, several genome mining methods were verified to successfully recover genomes from activated sludge such as hybrid assembly of the second- and third-generation sequencing.ConclusionsThis work elucidated the proportion of MDM in WWTPs, defined the "wanted list" of activated sludge for future investigations, and certified potential genome recovery methods. The proposed methodology of this study can be applied to other ecosystems and improve understanding of ecosystem structure across diverse habitats. Video Abstract.

Abstract Background Microorganisms are responsible for nutrient removal and resource recovery in wastewater treatment plants (WWTPs), and their diversity is often studied by 16S rRNA gene amplicon sequencing. However, this approach underestimates the abundance and diversity of Patescibacteria due to the low coverage of commonly used PCR primers for this highly divergent bacterial phylum. Therefore, our current understanding of the global diversity, distribution, and ecological role of Patescibacteria in WWTPs is very incomplete. This is particularly relevant as Patescibacteria are considered to be associated with microbial host cells and can therefore influence the abundance and temporal variability of other microbial groups that are important for WWTP functioning. Results Here, we evaluated the in silico coverage of widely used 16S rRNA gene-targeted primer pairs and redesigned a primer pair targeting the V4 region of bacterial and archaeal 16S rRNA genes to expand its coverage for Patescibacteria. We then experimentally evaluated and compared the performance of the original and modified V4-targeted primers on 565 WWTP samples from the MiDAS global sample collection. Using the modified primer pair, the percentage of ASVs classified as Patescibacteria increased from 5.9 to 23.8%, and the number of detected patescibacterial genera increased from 560 to 1576, while the detected diversity of the remaining microbial community remained similar. Due to this significantly improved coverage of Patescibacteria, we identified 23 core genera of Patescibacteria in WWTPs and described the global distribution pattern of these unusual microbes in these systems. Finally, correlation network analysis revealed potential host organisms that might be associated with Patescibacteria in WWTPs. Interestingly, strong indications were found for an association between Patescibacteria of the Saccharimonadia and globally abundant polyphosphate-accumulating organisms of the genus Ca. Phosphoribacter. Conclusions Our study (i) provides an improved 16S rRNA gene V4 region-targeted amplicon primer pair inclusive of Patescibacteria with little impact on the detection of other taxa, (ii) reveals the diversity and distribution patterns of Patescibacteria in WWTPs on a global scale, and (iii) provides new insights into the ecological role and potential hosts of Patescibacteria in WWTPs . Video Abstract

In recent years, the ubiquitous occurrence of plastic debris has become a significant environmental concern, posing considerable harm to our ecosystems. Microplastics (MPs) (1 μm–5 mm) and nanoplastics (NPs) (

Vaccines combatting COVID-19 demonstrate the ability to protect against disease and hospitalization, and reduce the likelihood of death caused by SARS-CoV-2. In addition, monitoring viral loads in sewage emerges as another crucial strategy in the epidemiological context, enabling early and collective detection of outbreaks. The study aimed to monitor the viral concentration of SARS-CoV-2 in untreated sewage in a Brazilian municipality. Also, it attempted to correlate these measurements with the number of clinical cases and deaths resulting from COVID-19 between July 2021 and July 2022. SARS-CoV-2 viral RNA was quantified by RT-qPCR. Pearson's correlation was performed to analyze the variables’ relationship using the number of cases, deaths, vaccinated individuals, and viral concentration of SARS-CoV-2. The results revealed a significant negative correlation (p < 0.05) between the number of vaccinated individuals and the viral concentration of SARS-CoV-2, suggesting that after vaccination, the RNA viral load concentration was reduced in the sample population by the circulating concentration of wastewater. Consequently, wastewater monitoring, in addition to functioning as an early warning system for the circulation of SARS-CoV-2 and other pathogens, can offer a novel perspective that enhances decision-making, strengthens vaccination campaigns, and contributes to authorities establishing systematic networks for monitoring SARS-CoV-2. HIGHLIGHTS The presence of SARS-CoV-2 was detected in 100% of the wastewater samples.; Wastewater SARS-CoV-2 concentration negatively correlated with vaccinated individuals.; Wastewater-based epidemiology is a tool for the monitoring of virus during vaccination campaigns.;

To elucidate how rising temperatures influence native amphipods, and how the expansion of wastewater treatment plants (WWTPs) with a fourth purification stage can alter temperature-related effects, studies were conducted in anthropogenically influenced rivers in Southwest Germany. Gammarids were sampled up- and downstream of two WWTPs, and exposed to elevated temperatures in the laboratory. Gammarids separated from precopula pairs were more sensitive to exposure-related stress and to a temperature increase than animals that were not in the reproductive phase. Furthermore, females were significantly more sensitive than males. Adult gammarids sampled individually at the WWTP with three purification stages showed a similar tolerance to elevated temperature at the up- and downstream site. In contrast, mortality following heat stress was substantially lower in animals sampled downstream of the WWTP with four treatment stages than in those sampled at the upstream site. We assume that the increased sensitivity of artificially separated precopula pairings reflect the situation under high hydraulic stress after heavy rainfall. Our results further illustrate the importance of WWTP upgrades in the context of climate change: gammarids sampled downstream the upgraded fourth-stage WWTP were likely exposed to lower levels of micropollutants, and thus may have allocated energy from detoxification to heat stress responses.

At least 11 per-and polyfluorinated alkyl substances (PFASs) were more prevalent during the dry season, whereas only PFBA, L-PFBS, L-PFOS, and PFOA were prevalent during the wet season in 11 WWTPs. The ∑21 PFAS levels in the influent and the effluent ranged from 137 to 3327 ng/L and 265–7,699 ng/L in the dry season and 61–2,953 ng/L and 171–3,458 ng/L in the wet season, respectively. The highest mean concentrations were observed in the influent and effluent for PFOA (586 ng/L) and L-PFBS (552 ng/L); and FOET (1,399 ng/L) and PFNA (811 ng/L) during dry and wet seasons, respectively. During the wet season, 6:2 FTS was observed at the highest concentrations, exhibiting 4,900 ng/L (66%) and 2,351 ng/L (39%), 1,950 ng/L (53%) in SST and BNR, respectively. Principal component analysis (PCA), hierarchical clustering (HCA), and PFHpA/PFOA, PFBA/PFOA, and PFNA/PFOA ratios revealed mixtures of PFAS sources into WWTPs. HIGHLIGHTS PFASs were detected in 11 South African wastewater treatment plants.; PFASs varied seasonally and within different process units.; Perfluoroalkyl sulfonic acids and fluorotelomers accounted for high concentrations of PFASs in WWTPs.; For the first time, the study reports on fluorotelomers in South African WWTPs and; Statistical methods revealed a mixture of PFAS sources – domestic discharge and atmospheric precipitation.;

Per- and polyfluoroalkyl substances (PFAS) present a growing environmental and health concern globally. This study examines the state of PFAS research and management in the Gulf Cooperation Council (GCC) countries, including the United Arab Emirates, Kingdom of Saudi Arabia, Kuwait, Qatar, Bahrain, and Sultanate of Oman. A comprehensive search was conducted in the PubMed, Web of Science, and Scopus databases, including English-language literature without temporal constraints up until November 2023. The search specifically targeted primary research studies employing descriptive or observational methodologies that were published in peer-reviewed journals. The review focused on studies investigating PFAS in both human and environmental contexts within the GCC region. The NIH Quality Assessment Tools and PRISMA guidelines were employed to evaluate the quality of the included studies and report the results. Despite some progress in understanding PFAS, considerable knowledge gaps exist, particularly in wastewater treatment processes and environmental monitoring. The study underscores the need for enhanced research, monitoring, and regulatory strategies to address the environmental sustainability challenges posed by PFAS, ensuring the protection of public health and ecosystems in the GCC region.

Background: Microorganisms are responsible for nutrient removal and resource recovery in wastewater treatment plants (WWTPs), and their diversity is often studied by 16S rRNA gene amplicon sequencing. However, this approach underestimates the abundance and diversity of Patescibacteria due to the low coverage of commonly used PCR primers for this highly divergent bacterial phylum. Therefore, our current understanding of the global diversity, distribution, and ecological role of Patescibacteria in WWTPs is very incomplete. This is particularly relevant as Patescibacteria are considered to be associated with microbial host cells and can therefore influence the abundance and temporal variability of other microbial groups that are important for WWTP functioning. Results: Here, we evaluated the in silico coverage of widely used 16S rRNA gene-targeted primer pairs and redesigned a primer pair targeting the V4 region of bacterial and archaeal 16S rRNA genes to expand its coverage for Patescibacteria. We then experimentally evaluated and compared the performance of the original and modified V4-targeted primers on 565 WWTP samples from the MiDAS global sample collection. Using the modified primer pair, the percentage of ASVs classified as Patescibacteria increased from 5.9 to 23.8%, and the number of detected patescibacterial genera increased from 560 to 1576, while the detected diversity of the remaining microbial community remained similar. Due to this significantly improved coverage of Patescibacteria, we identified 23 core genera of Patescibacteria in WWTPs and described the global distribution pattern of these unusual microbes in these systems. Finally, correlation network analysis revealed potential host organisms that might be associated with Patescibacteria in WWTPs. Interestingly, strong indications were found for an association between Patescibacteria of the Saccharimonadia and globally abundant polyphosphate-accumulating organisms of the genus Ca. Phosphoribacter. Conclusions: Our study (i) provides an improved 16S rRNA gene V4 region-targeted amplicon primer pair inclusive of Patescibacteria with little impact on the detection of other taxa, (ii) reveals the diversity and distribution patterns of Patescibacteria in WWTPs on a global scale, and (iii) provides new insights into the ecological role and potential hosts of Patescibacteria in WWTPs. 9DpTXjuT--dysnV-FwKdBe Video Abstract [ABSTRACT FROM AUTHOR]

In recent years, the ubiquitous occurrence of plastic debris has become a significant environmental concern, posing considerable harm to our ecosystems. Microplastics (MPs) (1 μm–5 mm) and nanoplastics (NPs) (<1 μm) are noticeable in diverse forms, spreading throughout the environment. Notably, wastewater treatment plants (WWTPs) emerge as major contributors to the generation of MP and NP. Within these treatment plants, water influx from domestic and commercial sources carries a considerable load of MPs derived from items like fiber clothing, personal care products, and toothpaste. Lacking dedicated removal mechanisms, these MPs persist through the wastewater treatment process, ultimately entering natural water bodies and the soil environment. The novelty of this review lies in its detailed examination of contemporary methodologies for sampling, detecting, and eliminating MPs specifically from WWTPs. By critically assessing the efficacy of current removal techniques at various treatment stages, the review offers targeted insights into practical aspects of MP management in these facilities. As the study of micro/nano plastics is still in its early stages, this article aims to contribute by offering a comprehensive review of the methods utilized for plastic debris removal in both WWTPs and drinking water treatment plants (DWTPs). Furthermore, the article provides a comprehensive overview of the existing rules, regulations, and policies concerning MPs in the United States. This inclusion not only broadens the scope of the review but also establishes it as a valuable reference for understanding the regulatory framework related to MPs. This review uniquely combines a focused evaluation of WWTPs/DWTPs, an exploration of removal methods, and an examination of regulatory framework, making a different contribution to the review article. Through this review, we aim to enhance understanding and awareness of the multi-layered challenges posed by MPs, offering insights that can inform future research directions and policy initiatives. [ABSTRACT FROM AUTHOR]

Currently, one of the main goals is to make municipal wastewater treatment plants (WWTPs) energy-neutral. However, advanced wastewater treatments and sewage sludge processing are still classified as highly energy-intensive. In this study, the energy self-sufficiency potential assessment of the WWTP located in Krosno (Poland) was evaluated. Moreover, the possible paths for improving the energy balance of the analyzed facility are presented in this paper. The performed evaluation indicated that in 2016–2019, the energy consumption at WWTP Krosno varied from 0.25 to 0.71 kWh/m3 of wastewater (average 0.51 kWh/m3), and the highest energy utilization values in each year were recorded around the summer season. An analysis of the data showed that as the pollutant load flowing into the WWTP increased, its energy utilization decreased. Such results indicate that the treatment cost per cubic meter decreases as the load increases due to the capital cost being the same. The estimated self-sufficiency of the facility in the years analyzed was 50.5%. The average energy recovery from 1 m3 of wastewater was 0.27 kWh/m3, and the average energy recovery from 1 m3 of biogas was 1.54 kWh/m3. Since the energy balance of this wastewater treatment plant, determined primarily by the continuously increasing cost of energy purchases, has to be improved, two courses of action were identified that will allow for increasing self-sufficiency. The co-digestion strategy was indicated as the easiest solution to implement, given the on-going anaerobic stabilization of sewage sludge at this WWTP. Moreover, the possible co-substrates that can be obtained from local suppliers were indicated. The second course of action, which requires a thorough economic analysis, is sludge pre-treatment, which might improve sewage sludge properties, resulting in a more favorable biogas yield. [ABSTRACT FROM AUTHOR]

To elucidate how rising temperatures influence native amphipods, and how the expansion of wastewater treatment plants (WWTPs) with a fourth purification stage can alter temperature-related effects, studies were conducted in anthropogenically influenced rivers in Southwest Germany. Gammarids were sampled up- and downstream of two WWTPs, and exposed to elevated temperatures in the laboratory. Gammarids separated from precopula pairs were more sensitive to exposure-related stress and to a temperature increase than animals that were not in the reproductive phase. Furthermore, females were significantly more sensitive than males. Adult gammarids sampled individually at the WWTP with three purification stages showed a similar tolerance to elevated temperature at the up- and downstream site. In contrast, mortality following heat stress was substantially lower in animals sampled downstream of the WWTP with four treatment stages than in those sampled at the upstream site. We assume that the increased sensitivity of artificially separated precopula pairings reflect the situation under high hydraulic stress after heavy rainfall. Our results further illustrate the importance of WWTP upgrades in the context of climate change: gammarids sampled downstream the upgraded fourth-stage WWTP were likely exposed to lower levels of micropollutants, and thus may have allocated energy from detoxification to heat stress responses. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the impact of WWTP effluents on the sediment microbial communities throughout the Mureș River. This study shows the existence of an ecological equilibrium between the WWTP effluent disruptors and the resilience of the Mureș River sediment microbiomes, a fact that suggests the river's stable/balanced ecological status in this regard, partly due to the microbial communities' resilience to the local impact of WWTP effluents. High-throughput 16S bacterial metabarcoding was used to evaluate the bacterial communities in the sediment. Due to the lotic system's sediment microbial communities' sensitivity to environmental changes, we assumed the dependency of these community structures and functions on environmental abiotic and abiotic parameters. The study results show that, although bacterial communities are equally diverse in the three locations (upstream WWTP, WWTP effluents, and downstream WWTP), there is a difference in community structure between the upstream samples and the WWTP samples, while the downstream samples contain a mixture of the upstream and WWTP effluent communities. Just downstream of the WWTP sediment, microbial communities are influenced by the specific input from the WWTP effluents; nevertheless, the river sediment microbiome is resilient and able to further recover its natural microbial composition, as evidenced by the similarity in bacterial community structures at all upstream river locations. This study demonstrates the ecological equilibrium between the WWTP effluent disruptors and the resilience capacity of the Mureș River sediment microbiomes, a fact that indicates the river's stable/balanced ecological status, in part due to the microbial communities' resilience to the local impact of WWTP effluents. Based on these findings, a monitoring system should be implemented here in the future. [ABSTRACT FROM AUTHOR]

Non-target analyses were conducted to characterize and compare the molecular profiles (UHPLC-HRMS fingerprint) of water samples from a wastewater treatment plant (WWTP). Inlet and outlet samples were collected from three campaigns spaced 6 months apart in order to highlight common trends. A significant impact of the treatment on the sample fingerprints was shown, with a 65–70% abatement of the number of features detected in the effluent, and more polar, smaller and less intense molecules found overall compared to those in WWTP influent waters. Multivariate analysis (PCA) associated with variations of the features between inlets and outlets showed that features appearing or increasing were correlated with effluents while those disappearing or decreasing were correlated with influents. Finally, effluent features considered as relevant to a potentially adverse effect on aqueous media (i.e. those which appeared or increased or slightly varied from the influent) were highlighted. Three hundred seventy-five features common with the 3 campaigns were thus selected and further characterized. For most of them, elementary composition was found to be C, H, N, O (42%) and C, H, N, O, P (18%). Considering the MS2 spectra and several reference MS2 databases, annotations were proposed for 35 of these relevant features. They include synthetic products, pharmaceuticals and metabolites. [ABSTRACT FROM AUTHOR]

We present the first report of plastic biomedia contamination on Brazilian beaches based on evidence collected from 14 beaches of the Paraná state coastline (southern Brazil). Plastic biomedia, also called biocarriers, are small, perforated plastic pieces used worldwide in wastewater treatment plants (WWTP) that apply the Moving Bed Biofilm Reactor (MBBR) process. Accidental release of these particles into the environment adds to Ocean's long-term plastic pollution problem. A high amount of plastic biomedia presence in the coastal areas of Paraná was first noticed by a community member, who found 411 plastic particles on a beach located in Pontal do Paraná, bringing this issue to our attention. In this study, plastic biomedia was retrieved from drift line alongshore transects (0.3 to 1 km long) and cross-shore transects (5 m wide) from the water line to the backshore zone. A total of 749 items were collected from 11 of the 14 sampled beaches, including the Mel and Superagui Islands nature reserves. The decreasing trend in plastic biomedia abundance with the increase in distance of the PEC southern outlet suggests that these particles probably originate from a WWTP in the Paranaguá Estuarine Complex (PEC). Once in the water, these floating plastic particles that followed the suspended sediment transport pattern were exported to coastal waters and were transported by longshore currents. Highlighting the potential role of the PEC as a substantial vector for marine debris to the Paraná coastline. The most likely source of this novel plastic contaminant to the Brazilian coastline are WWTP with MBBR systems. Therefore, stakeholders need to discuss and establish a reporting system so that plastic biomedia spillovers or losses are reported, and its dispersal in the environment is reduced. [ABSTRACT FROM AUTHOR]

Accurate assessment of greenhouse gas emissions from wastewater treatment plants is crucial for mitigating climate change. N2O is a potent greenhouse gas that is emitted from wastewater treatment plants during the biological denitrification process. In this study, we developed and evaluated deep learning models for predicting N2O emissions from a WWTP in Switzerland. Six key parameters were selected to obtain the optimal LSTM model by adjusting experimental parameter conditions. The optimal parameter condition was achieved with 150 neurons, the tanh activation function, the RMSprop optimization algorithm, a learning rate of 0.001, no dropout regularization, and a batch size of 128. Under the same conditions, we compared the performance of recurrent neural networks (RNNs) and Long Short-Term Memory (LSTM) networks. We found that LSTM models outperformed RNN models in predicting N2O emissions. The optimal LSTM model achieved a 36% improvement in mean absolute error (MAE), a 19% improvement in root mean squared error (RMSE), and a 6.92% improvement in R2 score compared to the RNN model. Additionally, LSTM models demonstrated better resilience to sudden changes in the target sequence, exhibiting a 9.54% higher percentage of explained variance compared to RNNs. These results highlight the potential of LSTM models for accurate and robust prediction of N2O emissions from wastewater treatment plants, contributing to effective greenhouse gas mitigation strategies. [ABSTRACT FROM AUTHOR]

The spread of multidrug-resistant bacteria from humans or livestock is a critical issue. However, the epidemiology of resistant pathogens across wastewater pathways is poorly understood. Therefore, we performed a detailed comparison of third-generation cephalosporin-resistant Escherichia coli (3GCREC) from wastewater treatment plants (WWTPs) to analyze dissemination pathways. A total of 172 3GCREC isolated from four WWTPs were characterized via whole genome sequencing. Clonal relatedness was determined using multi-locus sequence typing (MLST) and core genome MLST. Resistance genotypes and plasmid replicons were determined. A total of 68 MLST sequence types were observed with 28 closely related clusters. Resistance genes to eight antibiotic classes were detected. In fluoroquinolone-resistant isolates, resistance was associated with three-or-more point mutations in target genes. Typing revealed high genetic diversity with only a few clonal lineages present in all WWTPs. The distribution paths of individual lines could only be traced in exceptional cases with a lack of enrichment of certain lineages. Varying resistance genes and plasmids, as well as fluoroquinolone resistance-associated point mutations in individual isolates, further corroborated the high diversity of 3GCREC in WWTPs. In total, we observed high diversity of 3GCREC inside the tested WWTPs with proof of resistant strains being released into the environment even after treatment processes. [ABSTRACT FROM AUTHOR]

The water separated by sludge treatment processes is known as the sidestreams, such as the centrate, underflow belt thickener, and supernatant gravity thickener. The sidestreams have significant amounts of contaminants, particularly nutrients, and are returned to the wastewater treatment plant head. Returning the sidestreams to the head of the plant causes both technical and financial problems. This paper models the effect of sidestreams on the treatment of mainstream in full-scale conventional activated sludge systems operated with anaerobic/anoxic/oxic (A2/O). The effects of sidestreams nutrients and inert materials, the pollutants fate in the A2/O system, oxygen consumed, and energy required by sidestreams are modeled using GPS-X8 simulation. The results showed that the discharge ratio of the sidestreams to the mainstream is 4 %. The proportion of the pollutants present in the sidestream to the mainstream were 4.3 %, 4.7 %, 8.8 %, 21 %, 40 %, and 11 % for BOD, COD, TSS, NH4, PO4, and H2S, respectively. The GPS-X model showed that high orthophosphate and hydrogen sulfide concentrations were seen in the anaerobic zone. While all other pollutants begin to decay, phosphates and hydrogen sulfide gas also begin to decrease gradually in anoxic and oxic zones, noting the high concentrations of nitrates and sulfates in the oxic zone. An added 10 % of oxygen is needed for the sidestreams ammonia oxidation, which is more than the amount needed for the oxidation of BOD. The percentage of alkali used to improve the nitrification process due to the ammonia in the sidestreams was 30 % of the specified amount of ammonia in the mainstream. This study proved that the plant's sidestreams adversely increased oxygen, energy, and alkali consumption.