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1,992 result(s) for "Raw sewage"
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Diversity of bacteria carrying antibiotic resistance genes in hospital raw sewage in Southeastern Brazil
In recent decades, antibiotic-resistant bacteria (ARB) emerged and spread among humans and animals worldwide. In this study, we evaluated the presence of ARB and antibiotic resistance genes (ARGs) in the raw sewage of two hospitals in Brazil. Sewage aliquots were inoculated in a selective medium with antibiotics. Bacterial identification was performed by MALDI-TOF and ARGs were assessed by polymerase chain reaction (PCR). A total of 208 strains from both hospitals were isolated (H1 = 117; H2 = 91). A wide variety of Enterobacterales and non-Enterobacterales species were isolated and most of them were Enterobacter spp. (13.0%), Proteus mirabilis (10.1%), and Klebsiella pneumoniae (9.6%). blaTEM and blaKPC were the most frequent β-lactamase-encoding genes and the predominant macrolide resistance genes were mph(A) and mel. Many species had the three tetracycline resistance genes (tetD, tetM, tetA) and strB was the prevalent aminoglycoside resistance gene. Two Staphylococcus haemolyticus strains had the mecA gene. Quinolone, colistin, and vancomycin resistance genes were not found. This study showed that hospital raw sewage is a great ARB and ARG disseminator. Strict monitoring of hospital sewage treatment is needed to avoid the spread of these genes among bacteria in the environment.
Study of the bactericidal properties of ZnO/Ag0 nanoparticles in the treatment of raw sewage effluents
In this work, the antimicrobial treatment of raw sewage effluents (RSE) of residences was studied. For this, the RSE was collected from a treatment plant and the antimicrobial activity was evaluated using Ag0 decorated ZnO nanoparticles. ZnO/Ag0 nanoparticles were synthesized by a microwave‐assisted hydrothermal method and sonochemical method. The effect of ZnO/Ag0 nanoparticles was evaluated by varying the concentration of the catalyst to the RSE, varying the amount of silver, and varying the contact time of the catalyst with the RSE, to optimize the process. The ZnO/Ag0 nanoparticles were characterized by X‐ray diffraction, surface area using the Brunauer‐Emmett‐Teller methodology, and field emission scanning electron microscopy. The results indicate that the particles synthesized by the association of sonochemical and hydrothermal methods provide a better antimicrobial result against all tested bacteria. The results obtained in this manuscript indicate an alternative methodology in the removal of 99% of the bacteria from tailings from a real sewer, showing its applicability in the treatment for later consumption.
Wastewater treatment alters microbial colonization of microplastics
Microplastics are ubiquitous contaminants in aquatic habitats globally, and wastewater treatment plants (WWTPs) are point sources of microplastics. Within aquatic habitats microplastics are colonized by microbial biofilms, which can include pathogenic taxa and taxa associated with plastic breakdown. Microplastics enter WWTPs in sewage and exit in sludge or effluent, but the role that WWTPs play in establishing or modifying microplastic bacterial assemblages is unknown. We analyzed microplastics and associated biofilms in raw sewage, effluent water, and sludge from two WWTPs. Both plants retained >99% of influent microplastics in sludge, and sludge microplastics showed higher bacterial species richness and higher abundance of taxa associated with bioflocculation (e.g. Xanthomonas ) than influent microplastics, suggesting that colonization of microplastics within the WWTP may play a role in retention. Microplastics in WWTP effluent included significantly lower abundances of some potentially pathogenic bacterial taxa (e.g. Campylobacteraceae ) compared to influent microplastics; however, other potentially pathogenic taxa (e.g. Acinetobacter ) remained abundant on effluent microplastics, and several taxa linked to plastic breakdown (e.g. Klebsiella , Pseudomonas , and Sphingomonas ) were significantly more abundant on effluent compared to influent microplastics. These results indicate that diverse bacterial assemblages colonize microplastics within sewage and that WWTPs can play a significant role in modifying the microplastic-associated assemblages, which may affect the fate of microplastics within the WWTPs and the environment.
Optimising sample preparation for FTIR-based microplastic analysis in wastewater and sludge samples: multiple digestions
The lack of standardised methodologies in microplastic research has been addressed in recent years as it hampers the comparison of results across studies. The quantification of microplastics in the environment is key to the assessment of the potential eco-toxicological impacts that this new category of emerging pollutants could have on terrestrial and aquatic species. Therefore, the need for protocols that are robust, simple and reliable together with their standardisation are of crucial importance. This study has focused on removal of organic matter with Fenton reagent from wastewater and sludge samples. This step of analysis was optimised by implementing a multi-digestion treatment on these samples that have high concentration of complex mixtures of organic matter, which interfere with microplastic enumeration. Moreover, this study targeted the detection of microplastics in the sub-hundred-micron size range due to the potential higher risks associated with smaller-sized particles and the limited data available from previous wastewater research. To show the validity of the method, triplicate samples of raw sewage, final effluent and sludge were independently spiked with two different sizes and types of microplastic polymers. Due to the various analytical stages required for the isolation of microplastics, time is a limiting factor in sample processing. The sequential digestion with Fenton reagent represents an inexpensive and time-efficient procedure for wastewater research providing effective degradation of organic material. These advantages over other currently available methods mean the method is suitable for analysis of large numbers of samples allowing robust monitoring data sets to be generated.
Evaluation of Methods for the Concentration and Extraction of Viruses from Sewage in the Context of Metagenomic Sequencing
Viral sewage metagenomics is a novel field of study used for surveillance, epidemiological studies, and evaluation of waste water treatment efficiency. In raw sewage human waste is mixed with household, industrial and drainage water, and virus particles are, therefore, only found in low concentrations. This necessitates a step of sample concentration to allow for sensitive virus detection. Additionally, viruses harbor a large diversity of both surface and genome structures, which makes universal viral genomic extraction difficult. Current studies have tackled these challenges in many different ways employing a wide range of viral concentration and extraction procedures. However, there is limited knowledge of the efficacy and inherent biases associated with these methods in respect to viral sewage metagenomics, hampering the development of this field. By the use of next generation sequencing this study aimed to evaluate the efficiency of four commonly applied viral concentrations techniques (precipitation with polyethylene glycol, organic flocculation with skim milk, monolithic adsorption filtration and glass wool filtration) and extraction methods (Nucleospin RNA XS, QIAamp Viral RNA Mini Kit, NucliSENS® miniMAG®, or PowerViral® Environmental RNA/DNA Isolation Kit) to determine the viriome in a sewage sample. We found a significant influence of concentration and extraction protocols on the detected viriome. The viral richness was largest in samples extracted with QIAamp Viral RNA Mini Kit or PowerViral® Environmental RNA/DNA Isolation Kit. Highest viral specificity were found in samples concentrated by precipitation with polyethylene glycol or extracted with Nucleospin RNA XS. Detection of viral pathogens depended on the method used. These results contribute to the understanding of method associated biases, within the field of viral sewage metagenomics, making evaluation of the current literature easier and helping with the design of future studies.
Metagenomic analysis of sewage for surveillance of bacterial pathogens: A release experiment to determine sensitivity
Accurate monitoring of gastro-enteric and other diseases in large populations poses a challenge for public health management. Sewage represents a larger population, is freely obtainable and non-subject to ethical approval. Metagenomic sequencing offers simultaneous, multiple-target analysis. However, no study has demonstrated the sensitivity of metagenomics for detecting bacteria in sewage. In this study, we spot-released 10 13 colony-forming units (CFU) of Staphyloccus hyicus (non-pathogenetic strain 842J-88). The strain was flushed down a toilet into the sewer in the catchment area of a public wastewater treatment plant (WWTP), serving a population of 36,000 people. Raw sewage was continuously sampled at the WWTP’s inlet over 30- and 60-minute intervals for a total period of seven hours. The experiment was conducted twice with one week in-between release days and under comparable weather conditions. For the metagenomics analyses, the pure single isolate of S . hyicus was sequenced, assembled and added to a large database of bacterial reference sequences. All sewage samples were analyzed by shotgun metagenome sequencing and mapped against the reference database. S . hyicus was identified in duplicate samples at both of two release days and these sequence fragment counts served as a proxy to estimate the minimum number of sick people or sensitivity required in order to observe at least one sick person at 95% probability. We found the sensitivity to be in the range 41–140 and 16–36 sick people at release days 1 and 2, respectively. The WWTP normally serves 36,000 people giving a normalized sensitivity in the range of one in 257 to 2,250 persons.
Bacterial Pathogens and Community Composition in Advanced Sewage Treatment Systems Revealed by Metagenomics Analysis Based on High-Throughput Sequencing
This study used 454 pyrosequencing, Illumina high-throughput sequencing and metagenomic analysis to investigate bacterial pathogens and their potential virulence in a sewage treatment plant (STP) applying both conventional and advanced treatment processes. Pyrosequencing and Illumina sequencing consistently demonstrated that Arcobacter genus occupied over 43.42% of total abundance of potential pathogens in the STP. At species level, potential pathogens Arcobacter butzleri, Aeromonas hydrophila and Klebsiella pneumonia dominated in raw sewage, which was also confirmed by quantitative real time PCR. Illumina sequencing also revealed prevalence of various types of pathogenicity islands and virulence proteins in the STP. Most of the potential pathogens and virulence factors were eliminated in the STP, and the removal efficiency mainly depended on oxidation ditch. Compared with sand filtration, magnetic resin seemed to have higher removals in most of the potential pathogens and virulence factors. However, presence of the residual A. butzleri in the final effluent still deserves more concerns. The findings indicate that sewage acts as an important source of environmental pathogens, but STPs can effectively control their spread in the environment. Joint use of the high-throughput sequencing technologies is considered a reliable method for deep and comprehensive overview of environmental bacterial virulence.
Placing sensors in sewer networks: A system to pinpoint new cases of coronavirus
We consider a proposed system that would place sensors in a number of wastewater manholes in a community in order to detect genetic remnants of SARS-Cov-2 found in the excreted stool of infected persons. These sensors would continually monitor the manhole’s wastewater, and whenever virus remnants are detected, transmit an alert signal. In a recent paper, we described two new algorithms, each sequentially opening and testing successive manholes for genetic remnants, each algorithm homing in on a neighborhood where the infected person or persons are located. This paper extends that work in six important ways: (1) we introduce the concept of in-manhole sensors, as these sensors will reduce the number of manholes requiring on-site testing; (2) we present a realistic tree network depicting the topology of the sewer pipeline network; (3) for simulations, we present a method to create random tree networks exhibiting key attributes of a given community; (4) using the simulations, we empirically demonstrate that the mean and median number of manholes to be opened in a search follows a well-known logarithmic function; (5) we develop procedures for determining the number of sensors to deploy; (6) we formulate the sensor location problem as an integer nonlinear optimization and develop heuristics to solve it. Our sensor-manhole system, to be implemented, would require at least three additional steps in R&D: (a) an accurate, inexpensive and fast SARS-Cov-2 genetic-remnants test that can be done at the manhole; (b) design, test and manufacture of the sensors; (c) in-the-field testing and fine tuning of an implemented system.
Molecular detection of human adenovirus in urban wastewater in Egypt and among children suffering from acute gastroenteritis
Incidence of enteric viruses in sewage, the efficacy of wastewater treatment plants to remove these viruses, and health effects from their release into the surface water are very important environmental issues in the microbiology field. One of the most pathogenic enteric viruses is adenovirus which can cause a serious disease such as gastroenteritis with low grade fever and mild dehydration in humans. In this study we performed qualitative polymerase chain reaction (PCR) analysis of HAdV on 60 stool samples from children with acute gastroenteritis admitted to Abu-Rish hospital and 96 environmental samples (32 raw sewage, 32 treated sewage, 32 sewage sludge) collected from Zenin wastewater treatment plant (WWTP). HAdV were detected in 17 (28.3%) of stool, 27 (84.4%) of raw sewage, 16 (50%) of treated sewage and 25 (78%) of sludge samples. The viral concentrations were in the range of 2.02 × 106–7.23 × 106, 8.7 × 105–4.3 × 106, 1.22 × 104–3.7 × 106 and 1.48 × 106–1.77 × 107 GC/mL in stool, raw sewage, treated sewage, and sludge, respectively. HAdV was detected throughout the whole year of sample collection. Moreover, our results suggested that males were more susceptible to adenovirus infections than females. The results indicate that the high incidence of HAdV in the treated sewage may cause adverse health effects. This article has been made Open Access thanks to the generous support of a global network of libraries as part of the Knowledge Unlatched Select initiative.