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The increasing focus on sustainability and the circular economy has brought waste-to-energy technologies to the forefront of renewable energy research. However, the environmental impacts and management of contaminants associated with these technologies remain critical issues. This article comprehensively reviews the environmental impacts of converting sewage sludge into energy and fertilizers, focusing on managing potential contaminants and assessing the implications and ecological risks. It also highlights the latest trends in waste-to-energy technologies, waste-to-soil amendment, and their integration into circular economy frameworks. The discussion encompasses challenges and opportunities in optimizing these processes in wastewater treatment plants to minimize pollutants and enhance sustainability. Addressing these challenges is essential for ensuring the long-term viability and acceptance of waste-to-energy solutions, making this topic highly relevant and timely. [ABSTRACT FROM AUTHOR]

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 emergence of antibiotic resistance (AR) poses a significant threat to both public health and aquatic ecosystems. Wastewater treatment plants (WWTPs) have been identified as potential hotspots for disseminating AR in the environment. However, only a limited number of studies have been conducted on AR dissemination through WWTPs in Sri Lanka. To address this knowledge gap in AR dissemination through WWTP operations in Sri Lanka, we critically examined the global situation of WWTPs as hotspots for transmitting antibiotic-resistant bacteria (ARB) and antibiotic-resistant genes (ARGs) by evaluating more than a hundred peer-reviewed international publications and available national publications. Our findings discuss the current state of operating WWTPs in the country and highlight the research needed in controlling AR dissemination. The results revealed that the impact of different wastewater types, such as clinical, veterinary, domestic, and industrial, on the dissemination of AR has not been extensively studied in Sri Lanka; furthermore, the effectiveness of various wastewater treatment techniques in removing ARGs requires further investigation to improve the technologies. Furthermore, existing studies have not explored deeply enough the potential public health and ecological risks posed by AR dissemination through WWTPs. [ABSTRACT FROM AUTHOR]

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 circular economy, as a new model of waste management through energy self-sufficiency and valorisation, can be applied to wastewater treatment plants (WWTPs). Screening waste from WWTP pretreatment is the only waste that is not energetically recovered and thus constrains the achievement of zero waste. Previous studies demonstrated the technical feasibility of producing solid recovered fuel (SRF) from this waste. Environmental benefits, including waste reduction, resource conservation, or reduced greenhouse gas emissions are analysed in this work. Environmental impact is quantified using the life cycle assessment (LCA) methodology through the SimaPro 9.2. software and the CML-IA baseline v3.08 impact methodology, that propose 11 impact categories. Five scenarios were established to compare current landfill disposal with the production of densified and non-densified SRF using solar and thermal drying. Within the system boundaries studied, from waste generation to SRF production, results show that landfill is the most environmentally damaging option while producing non-densified SRF using solar drying is the most environmentally viable scenario. [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]

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]

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]

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]

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]

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]

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]

Wastewater treatment plants release substantial amounts of microplastics (MPs) into the environment. Various models and scenarios have been developed to estimate the sources and concentrations of MPs released by effluents. However, no model has included wastewater from washing machines. This study aims to estimate, in three scenarios, the number of MPs that are released by Bucharest households into the municipal wastewater treatment plant. The highest number of MPs has been estimated to be emitted by washing machines from synthetic clothing. From the category of cosmetics, the highest number of particles per year is potentially generated by face and hand creams. It has been estimated that the effluent of the wastewater treatment plant contains 48–4251 MP L−1 for the three proposed scenarios. The study shows that the population of Bucharest can generate high numbers of MPs, even in the minimum scenario. However, the use of MPs is expected to decrease, due to implementation of European Union policies, responsible consumer behavior, effective plastic waste management, and improved detection and separation technologies. [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]

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]

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]

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]

Bioaerosol emission at various WWTP treatment units has drawn attention due to their potential negative impacts on human health. This study conducted a bibliometric analysis of the global research on bioaerosol emissions from WWTPs from 1995 to 2022. The Scopus database was used to identify relevant articles and research trends, major contributors in the field, and recent developments. The study examined 122 articles in the field of bioaerosols in WWTPs. The analysis findings showed that publications and citations peaked in 2022, with values of 25 and 818, respectively. At the beginning of the study period, the USA, Poland, and Italy led the publications' ranking, but with time, China emerged as the most influential country in the field. Recent advances in the field have revealed that spectral intensity bioaerosol sensors have contributed to the faster and more reliable identification and classification of bioaerosols. It was also observed that probabilistic techniques relying on mathematical models and assumptions to ascertain the risks associated with bioaerosols may result in false interpretations. Despite their high cost, epidemiological studies were best for assessing plant workers' health risks. The outbreak has raised questions about accurately evaluating and modeling SARS-CoV-2 persistence, infectivity, and aerosolization over WWTP sites and environmental factors. Finally, the study highlighted the potential of three control treatment approaches: carbon absorption, UV irradiation, and ozone treatments, which proved efficient in reducing bioaerosol emissions. [ABSTRACT FROM AUTHOR]

Poor management in the municipal waste disposal is a serious crisis for the health of the ecosystem and society. The implementation of the waste-to-energy projects can simultaneously recover the available energy in waste and significantly mitigate the environmental impacts of releasing waste into the environment. In this article, a novel bio-waste-driven multigeneration cycle (BW-MGC) integrated with a solar thermal field for the production of various valuable products from sewage sludge is introduced and evaluated (from thermodynamic, environmental and economic points of view). Herein, the biogas and syngas are obtained through the anaerobic digestion and gasification processes, respectively. Besides that, hydrogen energy and water production cycles are based on the water-gas shift reaction and atmospheric water harvesting cycle (AWHC) units, respectively. In the offered project, the heating capacity and a part of the electricity are obtained through the waste heat recovery system. The offered project provides a new process with a novel structure and configuration to produce useful products. Moreover, it can jointly address the simultaneous issues of energy, water, and environment. The offered plant can produce 18.1 MW of electricity, 18.72 l/h of water, and 0.9 kg/s of hydrogen fuel. The energy efficiency of the system in such design conditions was calculated as 36.12%, while the exergy efficiency was 40.9%. Further, the exergy sustainability factor, total products unit cost, and levelized total CO 2 emissions are calculated as 0.5281, 0.05168 USD/kWh, and 0.2124 kg/kWh, respectively. [ABSTRACT FROM AUTHOR]

The study aimed to assess the impacts on four township areas under Emfuleni Local Municipality of poor water quality from inadequate wastewater management. The failure of the municipality to upgrade and maintain the wastewater treatment facilities has been ongoing for many years and raw sewage spills have been observed on the streets. The objectives of the study were addressed through questionnaires directed at obtaining feedback from household and small business participants. In total, 260 respondents participated, and the results showed differences in the perceptions of impacts due to poor water quality per area of residence; these were significant at 99% confidence interval. Results showed concerns about the impact of wastewater and poor infrastructure on the livelihoods of both residents and business owners. In conclusion, the infrastructural problems resulting in water quality issues have caused severe socio-economic strain on residents and businesses alike. [ABSTRACT FROM AUTHOR]

Amidst a global discourse on energy resources, it is imperative to provide decision makers with a comprehensive overview of energy consumption (EC) associated with various projects, particularly wastewater treatment plants (WWTPs). Ensuring compliance with stringent effluent quality criteria in the treatment of municipal wastewater necessitates a substantial EC, representing a predominant factor contributing to the operational expenses incurred by WWTP. Machine learning (ML) techniques can contribute to the estimation of the WWTPs' EC, which requires efficient and accurate data. This article uses data from several municipal WWTP projects in Greece, which are examined in order to produce EC estimation models. Data were first statistically analyzed, according to the context of project attributes and the context of EC, and correlation analysis identified the appropriate predictive project variables. Then, the attribute selection function in Waikato Environment for Knowledge Analysis 3.8.4 (WEKA 3.8.4) software emphasized the most effective subset of variables. The extracted variables from the combination of the correlation analysis and the WEKA attribute function were used as input neurons for the construction of neural network (NN) models, in the Fast Artificial Neural Network Tool 1.2 (FANN Tool 1.2). The optimum NN model resulted in a mean squared error (MSE) of 8.99899 × 10−5 and was based on treatment capacity, flow rate, influent load, and served population as its inputs. Notably, the research highlights the potential generalizability of these models in Greece and beyond the Greek context, offering valuable tools for stakeholders to inform decision making, allocate resources efficiently, and improve energy-efficient designs, resulting in cost savings and sustainability benefits. [ABSTRACT FROM AUTHOR]

Nutrients such as nitrogen and phosphorus are typically considered detrimental to wetland values, but waterfowl can be numerous on nutrient-rich wetlands. Waterfowl were counted three to six times per year on nine treatment lagoons and associated wetlands (2,025 ha) at the Western Treatment Plant (south-east Australia) from 2000, to help maintain ecological values of this Ramsar-listed wetland as well as treating sewage for a large city (Melbourne). Up to 185,000 waterfowl were counted, varying with season, continental rainfall and lagoon operation. Nutrient levels were reduced on Lake Borrie lagoon in 2005 (as part of an Environmental Improvement Program) and restored in 2015. Waterfowl declined on Lake Borrie lagoon from 2005 when it received treated effluent not raw sewage, and increased in 2015 when it received partially treated sewage. This pattern was highly significant for total waterfowl and most species and guilds at Lake Borrie but was not replicated on other lagoons. Modelling revealed positive relationships between waterfowl numbers and nutrient concentrations, including ammonia and nitrite, to moderate levels. This shows that with careful management nutrient enrichment can have positive benefits, allowing artificial wetlands such as wastewater treatment plants to support high densities of waterbirds and the food webs that sustain them. [ABSTRACT FROM AUTHOR]

The seismic vulnerability of public buildings must be estimated using structural or non-structural parameters. Scientists ought to investigate these factors for the estimation and analysis of lifelines such as wastewater treatment plants (WWTPs). Although efforts have been made in the past, the serious non-structural and operational parameters are not enough defined. This study considers the amount of shortening of the supposed factors after the literature retrieval of WWTPs' damages at sixteen severe earthquake events worldwide and three events from Greece. The corresponding parameters used for "ordinary structures" are taken into account. The most severe factors for non-structural vulnerability are seven while for operational vulnerability are nine, including soil, water and air pollution, respectively. These factors can assist the rapid qualitative estimation of seismic vulnerability. Implementing these agents by introducing them to an empirical estimation method will mitigate the seismic risk against the WWTPs, in parallel with measures adopted. [ABSTRACT FROM AUTHOR]

Artificial Intelligence (AI) has recently emerged as a powerful tool with versatile applications spanning various domains. AI replicates human intelligence processes through machinery and computer systems, finding utility in expert systems, image and speech recognition, machine vision, and natural language processing (NLP). One notable area with limited exploration pertains to using deep learning models, specifically Recurrent Neural Networks (RNNs), for predicting water quality in wastewater treatment plants (WWTPs). RNNs are purpose-built for handling sequential data, featuring a feedback mechanism. However, standard RNNs may exhibit limitations in accommodating both short-term and long-term dependencies when addressing intricate time series problems. The solution to this challenge lies in adopting Long Short-Term Memory (LSTM) cells, known for their inherent memory management through a 'forget gate' mechanism. In general, LSTM architecture demonstrates superior performance. WWTP data represent a historical series influenced by fluctuating environmental conditions. This study employs simple RNNs and LSTM architecture to construct prediction models for effluent parameters, systematically assessing their performance through various training data scenarios and model architectures. The primary objective was to determine the most suitable WWTP dataset model. The study revealed that an epoch setting of 50 and a batch size of 100 yielded the lowest training time and root mean square error (RMSE) values for both RNN and LSTM models. Furthermore, when these models are applied to predict effluent parameters, they exhibit precise RMSE values for all parameters. The study results can be applied to detect potential upsets in WWTP operations. [ABSTRACT FROM AUTHOR]

Little were certain about how wastewater treatment plants (WWTPs) affected the Japanese riverine microplastic contamination. This study explored the influences of WWTPs on microplastic pollution, assessed ecological risks, and looked at the sources-to-sinks phenomenon (WWTPs-to-rivers-to-marine) in riverine settings in Japan's Yamaguchi prefecture. Fifty surface water samples from the five selected rivers (Koya, Saba, Shimaji, and Fushino, Nishiki) and 11 effluent samples from WWTPs in the rivers' catchment were examined. Microplastics were analyzed using filtration, wet-peroxidation, density-separation, and attenuated reflectance-Fourier transform infrared spectroscopy techniques. Results suggested that the less populated and rural river (Nishiki) was less contaminated compared to the WWTPs and urban areas affected rivers (Koya, Saba, Shimaji, and Fushino). The WWTPs increased microplastic abundance twofold in the downstream regions compared to upstream stations. Microplastic characterization showed that the smaller microplastics < 500 µm, fiber-shaped, transparent, blue, and green color particles were major. Polymer identification demonstrated that the polyethylene, polypropylene, and polyethylene terephthalate were prevalent both for the rivers and WWTP effluents. There was a significant emission of microplastics from WWTPs to rivers (4.671 billion pieces per day; 71.8 kg per day) and rivers to Seto Inland Sea (0.13/billion pieces per day/km2; 7.1 kg per day). The per capita MP emissions to the rivers via WWTPs ranged from 0.02 to 6.49 g per day, which was approximately 2% of per capita single-use plastic wastes in Japan. An assessment of ecological risks showed that the WWTPs posed high ecological risks to rivers, and built up the pollution hotspots to their downstream areas by releasing higher number of microplastics and highly toxic polymers. Overall, the WWTPs influenced the rivers through both abundances and characteristics (shapes-size-color-polymers), increased the complexity of microplastic compositions as well as elevated ecological risks in the rivers. This study contributed to bridging the knowledge gaps about microplastic sources-to-sinks, ecological risks, and pollution management in Japan and beyond. [ABSTRACT FROM AUTHOR]

Wastewater treatment plants (WWTPs) have been identified as a source of microplastics, an emerging contaminant class of increasing concern, to the environment. Three WWTPs in the Canterbury region, New Zealand, were sampled bi-monthly from winter (June) to summer (December), to assess the variability of the abundance, morphology and polymer type of microplastics present over time. Microplastics were isolated from effluent via wet-sieving (300 μm and 1 mm) and wet peroxide oxidation (WPO) digest, and the polymer types determined using micro-Fourier-Transform Infrared Spectroscopy (μ-FTIR). Confirmed microplastics were detected at an average concentration of 1.3 ± 0.6 particles/L in effluent, with fragments comprising 58% of all morphotypes. Dominant polymer types detected were polyester, polyethylene, and polypropylene (26%, 22%, and 15%, respectively). The results of this study were comparable with those reported in international studies. An estimated 2.4 × 105 microplastics enter the receiving coastal environment daily from the discharge of effluent from the three WWTPs studied. No trends in microplastic concentration, morphotype and polymer type were observed in effluent samples from each WWTP, suggesting a common and continual source of microplastics into WWTPs. Further sampling is required to identify the factors that determine the variability of microplastics in WWTP influents and effluents. [ABSTRACT FROM AUTHOR]

SARS-CoV-2 can be detected in the feces of infected people, consequently in wastewater, and in bivalve mollusks, that are able to accumulate viruses due to their ability to filter large amounts of water. This study aimed to monitor SARS-CoV-2 RNA presence in 168 raw wastewater samples collected from six wastewater treatment plants (WWTPs) and 57 mollusk samples obtained from eight harvesting sites in Campania, Italy. The monitoring period spanned from October 2021 to April 2022, and the results were compared and correlated with the epidemiological situation. In sewage, the ORF1b region of SARS-CoV-2 was detected using RT-qPCR, while in mollusks, three targets—RdRp, ORF1b, and E—were identified via RT-dPCR. Results showed a 92.3% rate of positive wastewater samples with increased genomic copies (g.c.)/(day*inhabitant) in December–January and March–April 2022. In the entire observation period, 54.4% of mollusks tested positive for at least one SARS-CoV-2 target, and the rate of positive samples showed a trend similar to that of the wastewater samples. The lower SARS-CoV-2 positivity rate in bivalve mollusks compared to sewages is a direct consequence of the seawater dilution effect. Our data confirm that both sample types can be used as sentinels to detect SARS-CoV-2 in the environment and suggest their potential use in obtaining complementary information on SARS-CoV-2. [ABSTRACT FROM AUTHOR]

Aquatic environments are the final receptors of human emissions and are therefore contaminated by molecules, such as pharmaceuticals. After use, these compounds and their metabolites are discharged to wastewater treatment plants (WWTPs). During wastewater treatment, compounds may be eliminated or degraded into transformation products (TPs) or may be persistent. The aim of this study was to develop an analytical method based on high resolution mass spectrometry (HRMS) for the identification of six psychotropic drugs that are widely consumed in France and present in WWTPs, as well as their potential associated metabolites and TPs. Four out of six psychotropic drugs and between twenty-five and thirty-seven potential TPs were detected in wastewater, although this was based on full scan data. TPs not reported in the literature and specific to the study sites and therefore to the wastewater treatment processes were tentatively identified. For the selected drugs, most known and present TPs were identified, such as desmethylvenlafaxine or norcitalopram. Moreover, the short fragmentation study led rather to the identification of several TPs of carbamazepine as ubiquitous persistent TPs. [ABSTRACT FROM AUTHOR]

Effective environmental and energy management is crucial in the wastewater treatment sector. This article examines the implementation of biogas projects, which use anaerobic digestion to convert sewage sludge into energy and biofertilizer, in the Russian Federation. These projects, while common in the European Union, are rare in Russia due to financial constraints. Currently, they are primarily funded by utility operator investment programs, supported by tariffs for wastewater services. It is estimated that funding these projects through a five-year investment program would result in an annual tariff increase of 6-20% in the first two years. Additional financial mechanisms, such as 'green' credits and government interest rate compensation, have minimal impact on tariff growth. Any increase, however, can be burdensome for the population, and regional administrations may hesitate to implement these projects due to tariff concerns. Regardless, these projects are essential for Russia's transition to a circular economy. [ABSTRACT FROM AUTHOR]

For pharmacological reasons many active organic pharmaceutical substances (AOPSs) are singly or multiply halogenated. Halogenation can confer optimised steric fitting of an AOPS to its molecular receptor; moreover, by increasing the lipophilicity of a compound, passive permeation through bilipid membranes into target cells is enhanced. As halogenation is widely suspected to inhibit biodegradability in wastewater treatment plants, the relationship of halogenation vs. ready biodegradability was investigated. Among 230 AOPSs with empirical ready biodegradability data, all 70 halogenated AOPSs are not readily biodegradable, and halogenation is confirmed to be an impediment to ready biodegradability. As a counterexample to halogenation, hydrophilic substitutions (hydroxy, carboxylic-acid or terminal-amine groups) are positively correlated with ready biodegradability. Regarding halogenation, therefore, pharmacological goals stand in stark contrast to environmental goals. Possible ideas toward solutions for this contradiction are discussed. [ABSTRACT FROM AUTHOR]

Wastewater treatment plants (WWTPs) are energy-intensive facilities that fulfill stringent effluent quality norms. Energy consumption prediction in WWTPs is crucial for cost savings, process optimization, compliance with regulations, and reducing the carbon footprint. This paper evaluates and compares a set of 23 candidate machine-learning models to predict WWTP energy consumption using actual data from the Melbourne WWTP. To this end, Bayesian optimization has been applied to calibrate the investigated machine learning models. Random Forest and XGBoost (eXtreme Gradient Boosting) were applied to assess how the incorporated features influenced the energy consumption prediction. In addition, this study investigated the consideration of information from past data in improving prediction accuracy by incorporating time-lagged measurements. Results showed that the dynamic models using time-lagged data outperformed the static and reduced machine learning models. The study shows that including lagged measurements in the model improves prediction accuracy, and the results indicate that the dynamic K-nearest neighbors model dominates state-of-the-art methods by reaching promising energy consumption predictions. [ABSTRACT FROM AUTHOR]

Antibiotics are an essential tool of modern medicine, contributing to significantly decreasing mortality and morbidity rates from infectious diseases. However, persistent misuse of these drugs has accelerated the evolution of antibiotic resistance, negatively impacting clinical practice. The environment contributes to both the evolution and transmission of resistance. From all anthropically polluted aquatic environments, wastewater treatment plants (WWTPs) are probably the main reservoirs of resistant pathogens. They should be regarded as critical control points for preventing or reducing the release of antibiotics, antibioticresistant bacteria (ARB), and antibiotic-resistance genes (ARGs) into the natural environment. This review focuses on the fate of the pathogens Enterococcus faecium, Staphylococcus aureus, Clostridium difficile, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacteriaceae spp. (ESCAPE) in WWTPs. All ESCAPE pathogen species, including high-risk clones and resistance determinants to last-resort antibiotics such as carbapenems, colistin, and multidrug resistance platforms, were detected in wastewater. The whole genome sequencing studies demonstrate the clonal relationships and dissemination of Gram-negative ESCAPE species into the wastewater via hospital effluents and the enrichment of virulence and resistance determinants of S. aureus and enterococci in WWTPs. Therefore, the efficiency of different wastewater treatment processes regarding the removal of clinically relevant ARB species and ARGs, as well as the influence of water quality factors on their performance, should be explored and monitored, along with the development of more effective treatments and appropriate indicators (ESCAPE bacteria and/or ARGs). This knowledge will allow the development of quality standards for point sources and effluents to consolidate the WWTP barrier role against the environmental and public health AR threats. [ABSTRACT FROM AUTHOR]

Abstract—The microbial diversity and community structure of activated sludge in the biological treatment units of five municipal WWTPs and two industrial WWTPs were studied. The results showed that industrial WWTPs had the lowest diversity and abundance of activated sludge microbial communities, indicating that industrial wastewater inhibited the growth of microbial communities. In the correlation analysis between environmental factors and microbial diversity indices, pH and COD showed a significant negative correlation with the number of OTUs and microbial diversity. The main dominant microbial genus were Hyphomicrobium, Acinetobacter, Novosphingobium, Acinetobacter, and Meiothermus. Both principal coordinate analysis (PCoA) and phylogenetic analysis showed large differences in the structure of municipal and industrial microbial community structure, indicating the uniqueness of the activated sludge community structure in industrial WWTPs. Gene function predictions indicated that LJ had higher metabolic function associated with inorganic salt and lipid metabolism. Further co-occurrence network analysis showed that many of the key industrial WWTPs belonged in the same module, suggesting that they had strong interspecific interactions but were relatively independent from other microorganisms in the municipal WWTPs. This study broadens our understanding of microbial community differences between municipal WWTPs and industrial WWTPs. [ABSTRACT FROM AUTHOR]

With the increasing demands for higher treatment efficiency, better effluent quality, and energy conservation in Urban Wastewater Treatment Plants (WWTPs), research has already been conducted to construct an optimized control system for Anaerobic-Anoxic-Oxic (AAO) process using a data-driven approach. However, existing data-driven optimization control systems for AAO mainly focus on improving effluent water quality and reducing energy consumption, therefore they lack consideration for the stability of bioreactors. Meanwhile, safety in the optimization control process is still missing, resulting in a lack of reliability in practical applications. In this study, long short-term memory based model-predictive control (LSTM-MPC) with safety verificationis developed for the real-time control of AAO. It is used to optimize the control of aeration volume, internal recirculation, and sludge internal recycle processes for both saving energy and maintaining the stability of the bioreactor operation. To ensure the safety of the control process, this study proposes three rationality verification methods based on historical operation experience. These methods are validated through data from a real-world WWTP in eastern China. The results show that the prediction model of LSTM-MPC is capable of accurately predicting the water quality variables of the AAO system, with mean square error (MSE) close to 2.64 and Nash–Sutcliffe model efficiency coefficient (NSE) of 0.99 on the validation dataset. The combination of LSTM-MPC and rationality verification achieves a stable control trajectory with a 7% reduction in oxygen usage compared to a conventional controller, demonstrating its efficacy as a safe and reliable control strategy for WWTPs. [ABSTRACT FROM AUTHOR]

Wastewater treatment plants (WWTPs) are the important source of micro(nano)plastics (MNPs) and pollutants (e.g. chemicals, antibiotic resistance genes (ARGs) and pathogens) in natural environment, where the interaction in these co-existing substances has become an increasing concern. This work outlines the sources of MNPs and their interaction with pollutants in WWTPs, and assesses the potential risks after being discarded into natural environment. The sources of MNPs in WWTPs mainly include personal care products, washing clothes, surface runoff and atmospheric deposition as well as the inherent plastic equipment in WWTPs. MNPs can interact with various pollutants including ARGs and microorganisms, and organic and inorganic chemicals such as persistent organic pollutants antibiotics, and metals mainly through π-π, hydrophobic, electrostatic and hydrogen-bonding interactions and biofilm formation. Additionally, the WWTP conditions (e.g. pH, temperature) and components (e.g. dissolved organic matter, salinity and suspended particulates) can affect the interaction processes by modifying the sorption sites of MNPs and changing the property of MNPs and pollutants. Once being discharged into natural media, the individual and joint toxicological impacts of MNPs and associated pollutants to organisms via ingestion would be induced. As for the knowledge gap, more attentions should be focused on the contribution in various sources of MNPs and their interaction (especially submicron- to micron-size ranges) with ARGs, to improve understanding of the sources and pollution of MNPs and the combined risk with pollutants in natural environment. [ABSTRACT FROM AUTHOR]

Beta-agonist pharmaceuticals are widely used in humans and livestock for disease treatment, legal or illegal growth promotion in food animals, bodybuilding, weight loss, and sports doping. The occurrence of beta-agonists in wastewater treatment plants and their subsequent environmental impacts require greater attention. This study determined the levels of 12 beta-agonists in a wastewater treatment plant and evaluated their ecotoxicological risks as well as consumption levels and risks to human health. Among the 12 selected beta-agonists, all were detected in wastewater and 11 in sludge. In most cases, the concentrations of beta-agonists were higher in spring than in summer. Their total average daily mass loads per capita in the influent and effluent were 1.35 μg/d/p and 2.11 μg/d/p, respectively. The overall removal efficiencies of individual beta-agonists ranged from -295.3 to 71.2%. Ecotoxicological risk assessment revealed a low risk to daphnid and green algae from the levels of fenoterol and the mixture of 12 selected beta-agonists in the effluent. The daily consumption levels of individual beta-agonists per capita were 0.028–1.200 μg/d/p. Regular monitoring of beta-agonists in municipal sewage systems and their risk assessment based on toxicological data are urgently required in the future. [ABSTRACT FROM AUTHOR]

Background: Wastewater 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. Results: Compared 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. Conclusions: This 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. Ed3xU4yrM6Da7r9rFgJoVi Video Abstract [ABSTRACT FROM AUTHOR]

The seasonal distribution and dynamic evolution of antibiotics in wastewater from main treatment areas and in sludge and their resistance selection potential and ecotoxicological risk were studied at a municipal wastewater treatment plant in Jinan, East China. Ten antibiotics were selected, and all were detected in wastewater and sludge samples, with fluoroquinolones showing the highest detection concentrations and frequencies. Seasonal fluctuations in the antibiotic concentrations in the influent, effluent, and sludge were observed, with the highest values in winter in most cases. The dynamic evolution of antibiotics during the treatment process differed among the seasons. The antibiotic removal efficiencies were incomplete, ranging from − 40.47 to 100%. Mass balance analysis showed that sulfonamides, roxithromycin, and metronidazole were mainly removed through biological processing, whereas fluoroquinolones, doxycycline, and chloramphenicol were removed through sludge adsorption. Levofloxacin, as well as a mixture of the 10 antibiotics from the effluent, could pose a low ecotoxicological risk to Daphnia in the receiving waters. Additionally, levofloxacin and ciprofloxacin in the effluent and ciprofloxacin and metronidazole in the sludge may facilitate the selection of antibiotic-resistant bacteria in the environment. [ABSTRACT FROM AUTHOR]