Quantification and cultivation of Helicobacter pylori (H. pylori) from various urban water environments: A comprehensive analysis of precondition methods and sample characteristics.

Substantial evidence suggests that all types of water, such as drinking water, wastewater, surface water, and groundwater, can be potential sources of Helicobacter pylori (H. pylori) infection. Thus, it is critical to thoroughly investigate all possible preconditioning methods to enhance the recovery of H. pylori, improve the reproducibility of subsequent detection, and optimize the suitability for various water types and different detection purposes. In this study, we proposed and evaluated five distinct preconditioning methods for treating water samples collected from multiple urban water environments, aiming to maximize the quantitative qPCR readouts and achieve effective selective cultivation. According to the experimental results, when using the qPCR technique to examine WWTP influent, effluent, septic tank, and wetland water samples, the significance of having a preliminary cleaning step becomes more evident as it can profoundly influence qPCR detection results. In contrast, the simple, straightforward membrane filtration method could perform best when isolating and culturing H. pylori from all water samples. Upon examining the cultivation and qPCR results obtained from groundwater samples, the presence of infectious H. pylori (potentially other pathogens) in aquifers must represent a pressing environmental emergency demanding immediate attention. Furthermore, we believe groundwater can be used as a medium to reflect the H. pylori prevalence in a highly populated community due to its straightforward analytical matrix, consistent detection performance, and minimal interferences from human activities, temperature, precipitation, and other environmental fluctuations.

Long-range hydrophobic force enhanced interfacial photocatalysis for the submerged surface anti-biofouling.

Developing anti-biofouling and anti-biofilm techniques is of great importance for protecting water-contact surfaces. In this study, we developed a novel double-layer system consisting of a bottom immobilized TiO2 nanoflower arrays (TNFs) unit and an upper superhydrophobic (SHB) coating along with the assistance of nanobubbles (NBs), which can significantly elevate the interfacial oxygen level by establishing the long-range hydrophobic force between NBs and SHB and effectively maximize the photocatalytic reaction brought by the bottom TNFs. The developed NBs-SHB/TNFs system demonstrated the highest bulk chemical oxygen demand (COD) reduction efficiency at approximately 80% and achieved significant E. coli and Chlorella sp. inhibition efficiencies of 5.38 and 1.99 logs. Meanwhile, the system showed a sevenfold higher resistance to biofilm formation when testing in a wastewater matrix using a wildly collected biofilm seeding solution. These findings provide insights for implementing nanobubble-integrated techniques for submerged surface protection.

Indigenous microbial community governs the survival of Escherichia coli O157:H7 in constructed wetlands.

The survival pattern of Escherichia coli O157:H7 (E. coli O157:H7) and its regulatory factors in natural environments have been widely studied. However, there is little information about the survival of E. coli O157:H7 in artificial environments, especially in wastewater treatment facilities. In this study, a contamination experiment was performed to explore the survival pattern of E. coli O157:H7 and its central control factors in two constructed wetlands (CWs) under different hydraulic loading rates (HLRs). The results showed that the survival time of E. coli O157:H7 was longer in the CW under the higher HLR. Substrate ammonium nitrogen and available phosphorus were the main factors that influenced the survival of E. coli O157:H7 in CWs. Despite the minimal effect of microbial α-diversity, some keystone taxa, such as Aeromonas, Selenomonas, and Paramecium, governed the survival of E. coli O157:H7. In addition, the prokaryotic community had a more significant impact on the survival of E. coli O157:H7 than the eukaryotic community. The biotic properties had a more substantial direct power on the survival of E. coli O157:H7 than the abiotic factors in CWs. Collectively, this study comprehensively disclosed the survival pattern of E. coli O157:H7 in CWs, which is an essential addition to the environmental behavior of E. coli O157:H7, providing a theoretical basis for the prevention and control of biological contamination in wastewater treatment processes.

Constructed wetlands as hotspots of antibiotic resistance genes and pathogens: Evidence from metagenomic analysis in Chinese rural areas.

In rural China, many constructed wetlands (CWs) have been developed to treat rural wastewater sustainably. However, due to the scarce information on those rural CWs, it is difficult to analyze the biological contaminants within those systems, such as antibiotic resistance genes (ARGs) and pathogens. Based on the data collected from two pilot-scale, one-year-observed CWs, for the first time, this study explored the accumulation of ARGs and pathogens using the metagenomic sequencing approach and SourceTracker analysis under different hydraulic loading rates. The Shannon index of ARGs in the effluent surpassed the level found in the influent. The DESeq2 analysis showed that up to 21.49% of the total pathogen species had increased relative abundance in the effluent compared with the influent. By combining the contribution of substrate and rhizosphere, the CW became a more influencing factor for ARGs and pathogens contamination than the influent. The network analysis revealed a critical but latent fact that the development of antibiotic-resistant pathogens is highly likely to be triggered by the co-occurrence of ARGs and pathogens. Collectively, from the aspect of biological risk, our study showed that CWs alone might not be an ideal solution for improving wastewater treatment in rural China.

Toward an intensive understanding of sewer sediment prokaryotic community assembly and function.

Prokaryotic communities play important roles in sewer sediment ecosystems, but the community composition, functional potential, and assembly mechanisms of sewer sediment prokaryotic communities are still poorly understood. Here, we studied the sediment prokaryotic communities in different urban functional areas (multifunctional, commercial, and residential areas) through 16S rRNA gene amplicon sequencing. Our results suggested that the compositions of prokaryotic communities varied significantly among functional areas. Desulfomicrobium, Desulfovibrio, and Desulfobacter involved in the sulfur cycle and some hydrolytic fermentation bacteria were enriched in multifunctional area, while Methanospirillum and Methanoregulaceae, which were related to methane metabolism were significantly discriminant taxa in the commercial area. Physicochemical properties were closely related to overall community changes (p < 0.001), especially the nutrient levels of sediments (i.e., total nitrogen and total phosphorus) and sediment pH. Network analysis revealed that the prokaryotic community network of the residential area sediment was more complex than the other functional areas, suggesting higher stability of the prokaryotic community in the residential area. Stochastic processes dominated the construction of the prokaryotic community. These results expand our understanding of the characteristics of prokaryotic communities in sewer sediment, providing a new perspective for studying sewer sediment prokaryotic community structure.

Impact analysis of hydraulic loading rate on constructed wetland: Insight into the response of bulk substrate and root-associated microbiota.

Constructed wetland (CW) is an environment-friendly and low-cost technology for nutrients removal from domestic wastewater. For a well-tuned CW, hydraulic loading rate (HLR) is one of the critical factors, particularly under the challenging circumstance of more frequent heavy rainfall events brought by global warming. In this study, a comprehensive investigation was conducted to explore the influence of different HLRs on the CW's bulk substrate and root-associated microbiota aiming to yield new insight for CW management from a hybrid perspective of environmental microbiology and engineering science. The response of the microbial community and associated nutrients removal performance under different HLR settings were analyzed after a one-year operation. Results showed that the bulk substrate and rhizosphere genera involved in desulfurization and denitrification, such as Ferritrophicum, Sulfurimonas, and Sulfurisoma, were enriched in the higher HLR condition and associated with the higher total nitrogen (TN) and nitrate nitrogen (NO3--N) removal compared to the lower HLR condition. Co-occurrence network analysis demonstrated a more complex network under the higher HLR condition. Besides, it was observed that more stochastic in microbial assembly under the higher HLR condition. Surprisingly, zoonotic pathogens were observed and showed a greater prevalence under the higher HLR condition, indicating the potential correlation between HLR and pathogen intrusion. Collectively, this study revealed that the microbiota could be significantly altered under different HLR conditions, thereby resulting in differences in nutrients removal performance.

Voltammetric detection of arsenic (III) using gold nanoparticles modified carbon screen printed electrodes: Application for facile and rapid analysis in commercial apple juice.

This paper describes a voltammetric method and data analysis program developed for the detection of arsenic(III) in commercial apple juice. Arsenic(III) was detected using square wave stripping voltammetry with gold nanoparticle modified screen printed electrodes. The only sample pretreatment performed was the addition of a 100 mM phosphate buffer with a pH of 7. To compensate for interference from high ascorbic acid concentrations, a data analysis program was developed in MATLAB to fit a non-linear baseline, allowing for accurate peak height measurement. With this data analysis program, the developed methodology had a sensitivity of 0.1007 µA (µg L-1)-1 and a limit of detection of 16.73 µg L-1. A comparison between the voltammetric method and graphite furnace atomic absorption spectroscopy showed no bias in the voltammetric results and a good correlation between the two sets of predicted concentrations, with an R2 of 0.939.

Primary concentration - The critical step in implementing the wastewater based epidemiology for the COVID-19 pandemic: A mini-review.

The recent outbreak of a novel coronavirus SARS-CoV-2 has posed a significant global public health threat and caused dramatic social and economic disruptions. A new research direction is attracting a significant amount of attention in the academic community of environmental sciences and engineering, in which rapid community-level monitoring could be achieved by applying the methodology of wastewater based epidemiology (WBE). Given the fact that the development of a mass balance on the total number of viral RNA copies in wastewater samples and the infected stool specimens is the heart of WBE, the result of the quantitative RNA detection in wastewater has to be highly sensitive, accurate, and reliable. Thus, applying effective concentration methods before the subsequent RNA extraction and RT-qPCR detection is a must-have procedure for the WBE. This review provides new insights into the primary concentration methods that have been adopted by the eighteen recently reported COVID-19 wastewater detection studies, along with a brief discussion of the mechanisms of the most commonly used virus concentration methods, including the PEG-based separation, electrostatically charged membrane filtration, and ultrafiltration. In the end, two easy and well-proven concentration strategies are recommended as below, aiming to maximize the practical significance and operational effectiveness of the SARS-CoV-2 virus concentration from wastewater samples.

Simultaneous voltammetric detection of cadmium(II), arsenic(III), and selenium(IV) using gold nanostar-modified screen-printed carbon electrodes and modified Britton-Robinson buffer.

The present work reports a newly developed square wave anodic stripping voltammetry (SWASV) methodology using novel gold nanostar-modified screen-printed carbon electrodes (AuNS/SPCE) and modified Britton-Robinson buffer (mBRB) for simultaneous detection of trace cadmium(II), arsenic(III), and selenium(IV). During individual and simultaneous detection, Cd2+, As3+, and Se4+ exhibited well-separated SWASV peaks at approximately - 0.48, - 0.09, and 0.65 V, respectively (versus Ag/AgCl reference electrode), which enabled a highly selective detection of the three analytes. Electrochemical impedance spectrum tests showed a significant decrease in charge transfer resistance with the AuNS/SPCE (0.8 kΩ) compared with bare SPCE (2.4 kΩ). Cyclic voltammetry experiments showed a significant increase in electroactive surface area with electrode modification. The low charge transfer resistance and high electroactive surface area contributed to the high sensitivity for Cd2+ (0.0767 µA (0.225 µg L-1)-1), As3+ (0.2213 µA (µg L-1)-1), and Se4+ (µA (µg L-1)-1). The three analytes had linear stripping responses over the concentration range of 0 to 100 µg L-1, with the obtained LoD for Cd2+, As3+, and Se4+ of 1.6, 0.8, and 1.6 µg L-1, respectively. In comparison with individual detection, the simultaneous detection of As3+ and Se4+ showed peak height reductions of 40.8% and 42.7%, respectively. This result was associated with the possible formation of electrochemically inactive arsenic triselenide (As2Se3) during the preconcentration step. Surface water analysis resulted in average percent recoveries of 109% for Cd2+, 93% for As3+, and 92% for Se4+, indicating the proposed method is accurate and reliable for the simultaneous detection of Cd2+, As3+, and Se4+ in real water samples. Graphical abstract.

Voltammetric codetection of arsenic(III) and copper(II) in alkaline buffering system with gold nanostar modified electrodes.

One of the challenges preventing rapid, onsite voltammetric detection of arsenic(III) is the overlapping oxidation peak of copper(II). This paper describes a novel methodology for the voltammetric detection of trace levels of arsenic(III) in the presence of high copper(II) concentrations (up to the action level of 1.3 mg L-1 set by the US EPA for drinking water). Square wave stripping voltammetry tests were performed using disposable carbon screen printed electrodes modified with gold nanostars on samples buffered with Britton-Robinson buffer. The optimized parameters for accurate codetection of arsenic(III) and copper(II) were a buffer pH of 9.5, a loading of gold nanostars of 2.39*10-5 nmol per electrode, a deposition voltage of -0.8 V, and a deposition time of 180 s. Based on calibration testing, the limits of detection for arsenic(III) and copper(II) were determined to be 2.9 µg L-1 and 42.5 µg L-1, respectively. Furthermore, the linear ranges for arsenic and copper were 0-100 µg L-1 and 0-250 µg L-1 with sensitivities of 0.101 µA (µg L-1)-1 and 0.121 µA (µg L-1)-1, respectively. Interference testing was performed with several common ionic species, sodium bicarbonate, sodium chloride, tannic acid, iron(iii) chloride, magnesium chloride, calcium nitrate, and sodium sulfate, with only sodium bicarbonate significantly affecting the response. Validation testing in real-world samples was performed by comparison with graphite furnace atomic absorption spectroscopy. The validation testing demonstrated good accuracy and precision, expressed as percent recovery and relative standard deviation (RSD), respectively, in river water and tap water, with mean percent recoveries of 87.7% (RSD = 4.20%) and 83.2% (RSD = 10.02%), respectively.

Treatment train approaches for the remediation of per- and polyfluoroalkyl substances (PFAS): A critical review.

Per- and polyfluoroalkyl substances (PFAS) have recently drawn great attention due to their ubiquitous presence in aquatic environments and potential toxicity to human health and the environment. A number of recent studies have demonstrated that "passive" removal approaches, such as adsorption, filtration, and reverse osmosis or "active" degradation technologies, such as enhanced photolysis, electrochemical oxidation, and sonochemical destruction, are all able to individually conduct remedial measures for PFAS contamination at some level. However, drawbacks, specifically high energy consumption, low cost-efficiency, and extreme operating conditions, are commonly observed from these studies which significantly suppress the future for commercialization of these innovative technologies. Since 2015, a new trend of PFAS remediation has emerged that uses multiple synergetic technologies simultaneously (known as treatment train processes) to effectively achieve in-situ remediation of PFAS. This paper provides new insight of the recently reported treatment train studies selected from approximately 150 different publications with regards to the remediation of PFAS and discusses their innovative designs, remediation performances, present limits, and possible improvements. Based on a comprehensive review of the current treatment train studies, this review work proposes a new design that consists of three individual technologies, namely, nanofiltration, electrochemical anodic oxidation, and electro-Fenton degradation, to maximize economic and environmental benefits of PFAS remedial measures.