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1.
J Environ Manage ; 287: 112307, 2021 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-33798774

RESUMEN

During the last decade, water demand and wastewater generation has increased due to urbanization around the globe which had led to an increase in the utilization of chemicals/synthetic polymers for treating the wastewaters. These synthetic polymers used during the coagulation/flocculation process are non-renewable, non-biodegradable, and have a potential neurotoxic and carcinogenic effect. From the literature it is clear that extracellular polymer substance (EPS) is a potential bioflocculant, moreover it is renewable, biodegradable, eco-friendly, non-toxic as well as economically valued product. The various identification techniques and extraction methods of EPS are elaborated. Further application of EPS as absorbent in removing the dye from the industrial effluent is presented. Moreover EPS as a potential adsorbent for heavy metal removal from the various effluent is discussed. In addition, EPS is also utilized for soil remediation and soil erosion control. Mainly, EPS as bioflocculant in treating raw water, wastewater treatment, leachate and sludge management are summarized in this review.


Asunto(s)
Matriz Extracelular de Sustancias Poliméricas , Purificación del Agua , Floculación , Aguas del Alcantarillado , Aguas Residuales
2.
Nat Commun ; 12(1): 2009, 2021 03 31.
Artículo en Inglés | MEDLINE | ID: mdl-33790294

RESUMEN

Microorganisms play crucial roles in water recycling, pollution removal and resource recovery in the wastewater industry. The structure of these microbial communities is increasingly understood based on 16S rRNA amplicon sequencing data. However, such data cannot be linked to functional potential in the absence of high-quality metagenome-assembled genomes (MAGs) for nearly all species. Here, we use long-read and short-read sequencing to recover 1083 high-quality MAGs, including 57 closed circular genomes, from 23 Danish full-scale wastewater treatment plants. The MAGs account for ~30% of the community based on relative abundance, and meet the stringent MIMAG high-quality draft requirements including full-length rRNA genes. We use the information provided by these MAGs in combination with >13 years of 16S rRNA amplicon sequencing data, as well as Raman microspectroscopy and fluorescence in situ hybridisation, to uncover abundant undescribed lineages belonging to important functional groups.


Asunto(s)
Genoma Bacteriano/genética , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Metagenoma/genética , Metagenómica/métodos , ARN Ribosómico 16S/genética , Aguas del Alcantarillado/microbiología , Bacterias/clasificación , Bacterias/genética , Reactores Biológicos/microbiología , Dinamarca , Microbiota/genética , Filogenia , ARN Ribosómico 23S/genética , ARN Ribosómico 5S/genética , Aguas Residuales/microbiología , Purificación del Agua/métodos
3.
PLoS One ; 16(4): e0248893, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33831024

RESUMEN

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.


Asunto(s)
Algoritmos , Monitoreo del Ambiente , Eliminación de Residuos , Aguas del Alcantarillado/virología , Humanos
4.
Water Sci Technol ; 83(7): 1535-1547, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33843741

RESUMEN

The accumulation of toxic chemical constituents in sludge and wastewater has fuelled an interest in investigating efficient and eco-friendly wastewater remediation approaches. In this study, a set of bacterial samples were isolated from petroleum sludge and tested for their ability to degrade different aromatic pollutants, including azo dyes and emerging pollutants. Although exhibiting differential specificity, all bacterial isolates were able to degrade different classes of aromatic dyes efficiently. Ribosomal 16S rRNA sequencing of the 12 bacterial isolates showed that they belonged to two different bacterial genera: Bacillus cereus and Pseudomonas guariconensis. Of these 12 strains, MA1 (B. cereus) was the most promising and was chosen for further optimization and biochemical studies. The optimum culture and remediation conditions for MA1 was found to be at pH 7, with 100 ppm dye concentration, and under aerobic condition. In addition to efficiently degrading various aromatic dyes (e.g. Congo Red, Reactive Black 5, PBS, and Toluidine Blue), MA1 was also found to be capable of degrading various emerging pollutants (e.g. prometryn, fluometuron and sulfamethoxazole). Preliminary transcriptome analysis shows that MA1 grown on media containing a mixture of aromatic dyes appears to differentially express a number of genes. Data shown here strongly suggests that petroleum sludge is a rich reservoir of bacteria with powerful remediation abilities.


Asunto(s)
Bacillus , Contaminantes Ambientales , Petróleo , Bacillus cereus/genética , Biodegradación Ambiental , Pseudomonas , ARN Ribosómico 16S/genética , Aguas del Alcantarillado
5.
Water Sci Technol ; 83(7): 1566-1577, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33843743

RESUMEN

In this study, the conditioning effect of cationic polyacrylamide (CPAM) with different charge densities on raw sludge (RS) and thermo-hydrolyzed sludge (HS) pretreated with or without ferric salt is studied through orthogonal experiments. In addition, this paper uses the principles of rheology and morphology to analyze and clarify the conditioning mechanism of RS and HS, and reveals the mechanism of thermal hydrolysis to improve the dewatering performance of sludge. Compared with the RS, the HS has smaller particle size, better filterability, stronger fluidity and more obvious thixotropy. However, due to the influence of filter pressing time, ferric salt should be added before conditioning. The orthogonal experiment shows that the optimal conditioner is CPAM with charge density of 60, and the specific resistance to filtration and capillary suction time of the adjusted thermo-hydrolyzed sludge are reduced to (1.11 ± 0.07) × 1012 m/kg and 16.1 ± 1.8 s; the particle size increased from 61.2 to 253.5 µm. The moisture content of the sludge cake is about 48%. The structural strength and thixotropy of HS are higher than those of the RS, and can be greatly improved by adding ferric salt. Morphological analysis confirms that thermal hydrolysis can lyse microbial cells in sludge, and the sludge treated with ferric salt will have more porous structure and stronger flocculation strength.


Asunto(s)
Aguas del Alcantarillado , Agua , Resinas Acrílicas , Filtración , Floculación , Reología , Eliminación de Residuos Líquidos
6.
Indian J Med Res ; 153(1 & 2): 159-165, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33818473

RESUMEN

Background & objectives: Since its first recognition in Wuhan, China, in December 2019, the SARS-CoV-2 has spread rapidly across the world. Though SARS-CoV-2 spreads mainly via the droplets of respiratory secretions, it was also detected in stool samples of patients, indicating active infection of the gastrointestinal tract. Presence of SARS-CoV-2 RNA in sewage samples was reported in February 2020, raising the possibility of using environmental water surveillance to monitor SARS-CoV-2 activity in infected areas. The aim of this study was to standardize the methodology for detection of SARS-CoV-2 from sewage and explore the feasibility of establishing supplementary surveillance for COVID-19. Methods: Sewage specimens were collected from six sites in Mumbai, India, using the grab sample method and processed using polyethylene glycol (PEG)-dextran phase separation method for virus concentration. Real-time reverse transcription-polymerase chain reaction (RT-PCR) assay was used to detect the presence of SARS-CoV-2 RNA. Results: A total of 20 sewage samples collected from six different wards in Mumbai city, before the spread of SARS-CoV-2 infections and during May 11-22, 2020, were processed using the phase separation method. The WHO two-phase PEG-dextran method was modified during standardization. SARS-CoV-2 was found to concentrate in the middle phase only. All samples collected before March 16, 2020 were SARS-CoV-2 negative. Viral RNA was detected in sewage samples collected during the ongoing COVID-19 pandemic in all the six wards. Interpretation & conclusions: PEG-dextran phase separation method was effectively used to concentrate SARS-CoV-2 from domestic waste waters to detection levels. It would be feasible to initiate sewage surveillance for SARS-CoV-2 to generate data about the viral transmission in various epidemiologic settings.


Asunto(s)
/aislamiento & purificación , Aguas del Alcantarillado/virología , Monitoreo Epidemiológico , Humanos , India , Pandemias , ARN Viral/genética
7.
Recurso de Internet en Portugués | LIS - Localizador de Información en Salud | ID: lis-48069

RESUMEN

O projeto de vigilância do novo coronavírus em esgotos de Niterói, na Região Metropolitana do Rio de Janeiro, teve resultados publicados no periódico Water Research, uma prestigiada revista científica internacional.


Asunto(s)
Infecciones por Coronavirus/prevención & control , Monitoreo , Aguas del Alcantarillado/virología , Betacoronavirus/aislamiento & purificación
8.
Chemosphere ; 271: 129879, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33736214

RESUMEN

Membrane bioreactors (MBRs) are considered a promising tool for resource recovery in wastewater treatment. Nevertheless, membrane fouling is an inevitable phenomenon that deteriorates the MBR performance. Although many studies have attempted to elucidate the effect of sludge characteristics on MBR fouling, they posed certain limitations. Most of the previous studies focused on the initial sludge or employ the results of short-term batch tests without long-term transmembrane pressure (TMP) profiles in the interpretation of fouling behaviors. This study was conducted considering these limitations to determine the sludge characteristics most closely related to long-term TMP profiles and to identify their role in fouling behaviors. In long-term TMP profiles, critical time (tc; time to TMP jump) and fouling rates (the increase in the TMP slope) were used as fouling indexes, which were used to correlate with average values of sludge characteristics before and after experiments. According to the results, the concentration of the total soluble microbial product (SMP) and extracted extracellular polymeric substance (eEPS) in sludge significantly increased by 1.9 times and up to 28 times after experiment. The increase in the SMP and eEPS caused early TMP jumps and resulted in low-fouling rates by increasing particle size. Owing to the increase in the SMP and eEPS concentration, the origin of fouling potential was shifted from suspended solids to colloids and soluble materials. Fouling resistance caused by soluble material increased by up to 11.38 times.


Asunto(s)
Aguas del Alcantarillado , Purificación del Agua , Reactores Biológicos , Matriz Extracelular de Sustancias Poliméricas , Membranas Artificiales
9.
Sci Total Environ ; 769: 144642, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33736269

RESUMEN

The occurrence of man-made antibiotics in natural environment has aroused attentions from both scientists and publics. However, few studies tracked antibiotics from their production site to the end of disposal environment. Taking the coastal region of Hangzhou Bay as the study area, the fate of 77 antibiotics from 6 categories in two-step wastewater treatment plants (WTPs, i.e. pharmaceutical WTP and integrated WTP) was focused; and the antibiotics in both dissolved and adsorbed phases were investigated simultaneously in this study. The ubiquitous occurrence of antibiotics was observed in the two-step WTPs, with antibiotic concentrations following the order of PWTP (LOQ - 1.0 × 105 ng·L-1) > IWTPi (for industrial wastewater treatment, LOQ - 3.7 × 103 ng·L-1) > IWTPd (for domestic sewage treatment, LOQ - 1.3 × 103 ng·L-1). And the types of antibiotics detected in excess sludge and suspended particles were in accordance with those in wastewater. Quinolones were invariably dominant in both dissolved and adsorbed fractions. High removal efficiencies (median values >50.0%) were acquired for the dissolved quinolones (except for DFX), tetracyclines, ß-lactams, and lincosamides. Anaerobic/anoxic/oxic achieved the highest aqueous removal of antibiotics among the investigated treatment technologies in the three WTPs. PWTP and IWTP removed 9797 and 487 g·d-1 of antibiotics, respectively; and a final effluent with 126.4 g·d-1 of antibiotics was discharged into the effluent-receiving area (ERA) of Hangzhou Bay. Source apportionment analysis demonstrated that the effluents of IWTPd and IWTPd contributed respectively 39.3% and 8.9% to the total antibiotics in the ERA. The results illustrate quantitatively the antibiotic flows from engineered wastewater systems to natural water environment, on the basis of which the improvements of wastewater treatment technologies and discharge management would be put forward.


Asunto(s)
Aguas Residuales , Contaminantes Químicos del Agua , Antibacterianos/análisis , Bahías , China , Humanos , Aguas del Alcantarillado/análisis , Eliminación de Residuos Líquidos , Aguas Residuales/análisis , Agua , Contaminantes Químicos del Agua/análisis
10.
Environ Monit Assess ; 193(4): 175, 2021 Mar 10.
Artículo en Inglés | MEDLINE | ID: mdl-33751247

RESUMEN

Microplastics are widely detected in wastewater treatment plants. They can remove microplastics from wastewaters with a high yield, but it means that microplastics are transferred and accumulated to sewage sludge. Lately, increasing attention has been paid to microplastics in raw and treated wastewaters. However, studies about quantification and identification of microplastics in sewage sludge are very scarce and need to be further investigated. Since the sludge-based microplastics are newly studied and are a challenging matrix due to high organic content, there is limited knowledge of sampling, pre-treatment methods, identification techniques, and expression units. Besides, treated sewage sludge is mostly used for soil amendment to improve soil fertility and it gives economic advantages. This situation creates a pathway for microplastics entering the soil environment with unknown consequences. To the best of our knowledge, microplastics have a large specific surface area, small size, and hydrophobicity which makes it a good adsorbent for other pollutants. Therefore, the combined effect of microplastics with adsorbed pollutants such as heavy metals, antibiotics, and persistent organic pollutants could give serious harm to soil safety and soil organisms. Herein, new developments in the methods for sampling, pre-treatment, and identification techniques of microplastics in sewage sludge were reviewed. Then, the abundance of microplastics, major polymer types, and shapes in sewage sludge were examined. Finally, the effects and ecological risks of microplastic pollution as a result of agricultural usage of sewage sludge in the soil environment have been summarized. Also, the main points for future research were highlighted.


Asunto(s)
Metales Pesados , Contaminantes del Suelo , Monitoreo del Ambiente , Microplásticos , Plásticos , Aguas del Alcantarillado , Suelo , Contaminantes del Suelo/análisis
11.
Huan Jing Ke Xue ; 42(4): 1923-1929, 2021 Apr 08.
Artículo en Chino | MEDLINE | ID: mdl-33742827

RESUMEN

The specific ammonia uptake rates (SAUR) and ammonia oxidizing bacteria (AOB) community of influent sewage and activated sludge in the 2nd wastewater treatment plant (WWTP) of Xi'an without the primary settling tank were analyzed over multiple years to explore the seasonal effects of the influent AOB on the activated sludge systems. During the experiment, the SAUR of the raw sewage and activated sludge were 0.48-3.02 mg·(g·h)-1 and 0.68-2.25 mg·(g·h)-1, respectively. Meanwhile, the correlation analysis indicated that the monthly SAUR of the raw sewage was highly correlated with that of the activated sludge of the following month (r=0.862,P<0.05), which indicated that influent nitrifiers had a significant effect on the nitrification performance of activated sludge. Considering that the estimated AOB seeding intensities based on the ammonia oxidizing activity were 0.21-0.92 g·(g·d)-1, the nitrifier immigration from the raw sewage should added to the design of WWTP and the activated sludge modeling. Moreover, the qPCR results revealed that the AOB abundance of activated sludge in winter decreased but remained at 1010 cells·g-1, indicating that the immigration of influent nitrifiers could partially compensate for the reduction of the AOB abundance in the activated sludge caused by decreasing temperatures. Finally, the Illumina MiSeq sequencing demonstrated that the shared dominant AOB between the raw sewage and activated sludge were Nitrosomonas sp. Nm58, Nitrosomonas sp. JL21, and bacterium CYCU-0253. These findings can provide theoretical support for the design and operation of a WWTP.


Asunto(s)
Aguas del Alcantarillado , Purificación del Agua , Amoníaco , Bacterias/genética , Reactores Biológicos , Nitrificación , Oxidación-Reducción , Estaciones del Año
12.
Huan Jing Ke Xue ; 42(4): 1930-1938, 2021 Apr 08.
Artículo en Chino | MEDLINE | ID: mdl-33742828

RESUMEN

In order to clarify the characteristics of anaerobic ammonia oxidizing (ANAMMOX) sludge and the succession rule of bacteria based on particle size differentiation, the performance change and microbial community structure of ANAMMOX floc sludge during the formation of particles in the reaction system of a high ammonia-nitrogen biofilter were studied. The results indicated that the specific activity (SAA) and tolerance of the ANAMMOX granular sludge (AnGS) were significantly improved by increasing the particle size, and the SAA of R4(>4.75 mm) was up to 426.8 mg·(g·d)-1, but it also had adverse effects on mass transfer. The results of the high-throughput sequencing showed that dynamic changes between bacterial genera were common. When the particle size was less than 4.75 mm, the increase in particle size strengthened the stability of the bacterial flora, the ammonia oxidizing bacteria (AOB) with more flocs were eliminated, and the nitrogen removal ratio gradually stabilized. R3 (2.8-4.75 mm) exhibited the most specific flora composition, and the functional bacteria Candidatus Kuenenia accounted for 52.7%, while the R4 community complexity increased. Furthermore, the proportion of functional bacteria decreased, and the abundance of heterotrophic bacteria increased, which negatively affected the particle structure. In addition, the R3 microorganism has the best gene function expression level, which is significantly better than small particles in gene replication repair and energy conversion. Finally, the evolution of AnGS was analyzed through the OTU matrix between the samples. These results have some guiding significance for the optimization of the AnGS system and will be helpful for the application of the ANAMMOX process.


Asunto(s)
Amoníaco , Aguas del Alcantarillado , Anaerobiosis , Reactores Biológicos , Nitrógeno , Oxidación-Reducción , Tamaño de la Partícula
13.
Huan Jing Ke Xue ; 42(4): 1946-1955, 2021 Apr 08.
Artículo en Chino | MEDLINE | ID: mdl-33742830

RESUMEN

The effects of polyether sulfone (PES) microplastics and 2,4-dichlorophenol (2,4-DCP) on the loosely-bound extracellular polymeric substances (LB-EPS) and tightly-bound EPS (TB-EPS) of anaerobic granular sludge were investigated. In addition, high-throughput sequencing technology was used to analyze the changes in the microbial community and gene functions in the anaerobic granular sludge. The results revealed that the chemical oxygen demand (COD) removal rates of the 2,4-DCP and PES+2,4-DCP experimental groups were 35% and 37%, which were 57% and 55% lower than that of the blank control group, while the COD removal rates of the PES experimental group remained around 90%. After the addition of the PES microplastics and 2,4-DCP, the protein and polysaccharide contents in the LB-EPS decreased compared with the control group, and the polysaccharide content in TB-EPS increased the least. In presence of the PES microplastics and 2,4-DCP, the activity of coenzyme F420 was inhibited. Through high-throughput sequencing, the microbial richness and diversity of the anaerobic granular sludge in the experimental group were reduced with the addition of the PES microplastics or 2,4-DCP. In the control group and the experimental group, the dominant bacteria at the phylum level were Proteobacteria (13.45%-44.47%), Firmicutes (6.86%-21.67%), and Actinobacteria (3.16%-18.11%). The abundance of ß-Proteobacteria in the PES+2,4-DCP experimental group was reduced by 15.28%, while the abundance of γ-Proteobacteria increased by 28.44% compared with the control group. Based on the phylogenetic investigation of the communities using the reconstruction of unobserved states (PICRUSt) analysis, it was found that in the experimental group with the PES microplastics or 2,4-DCP, the genes related to the sludge energy metabolism function were 0.25%-0.72% more than the control group; therefore, the abundance of genes related to the transport function group decreased significantly.


Asunto(s)
Microbiota , Aguas del Alcantarillado , Anaerobiosis , Reactores Biológicos , Matriz Extracelular de Sustancias Poliméricas , Filogenia , Plásticos , Polímeros , Sulfonas , Eliminación de Residuos Líquidos
14.
Huan Jing Ke Xue ; 42(4): 1956-1966, 2021 Apr 08.
Artículo en Chino | MEDLINE | ID: mdl-33742831

RESUMEN

In urban solid waste management, the scientific and reasonable disposal and utilization of sewage sludge is becoming more and more important. It can be said that the pollution status and chemical properties of sewage sludge in urban sewage treatment plants can provide a basis for the scientific disposal and utilization of sludge. In this study, the characteristics of pH, moisture content, Cd, Cr, Cu, Zn, Pb, As, Hg, Ni, mineral oil, volatile phenol, PAHs, organic matter, nitrogen, phosphorus, and potassium were evaluated in sewage sludge collected from 49 sewage treatment plants in a certain city. The pollution status of heavy metals and organic pollutants, the frequency distribution of pollutant concentrations, and changes in the nutrient content were analyzed. The Nemero index and Hakanson potential ecological hazard index were used to assess the potential ecological risks of heavy metals in the agricultural utilization process of sludge. The results showed that under the condition of neutral pH values and high moisture content, the order of heavy metal content was Zn > Cu > Cr > Pb > Ni > As > Hg > Cd. The principal component analysis (PCA) results indicated that Cd, Pb, Hg, Ni, and As constituted the main load factors of the first main component of heavy metal sources. The most concentrated contents of 8 heavy metal frequency distributions among the 49 samples were 38.9-1380.0, 62.6-182.7, 63.6-181.3, 0.0-97.8, 19.3-68.4, 0.8-29.2, 0.3-8.7, and 0.01-0.96 mg·kg-1. In addition, the most concentrated frequency distribution of mineral oil, volatile phenol, and PAH concentration were 87.0%, 87.9%, and 77.6%, respectively. Moreover, the nutrient content of sludge was higher than the average level in China, and the organic matter content was 67.4%, 75.9%, and 92.5% of that of pig manure, cow dung, and chicken manure, while the content of nitrogen, phosphorus, and potassium was not very different. The Nemero index and Hakanson ecological hazard index results showed that the sludge of urban sewage treatment plant in the city has certain ecological risks. However, four sewage treatment plants were heavily polluted or highly ecologically hazardous among the 44 plants in this study, which were in line with the Standards for pollutant control of agricultural sludge. In summary, there are certain potential ecological risks for the agricultural utilization of sludge in the city, and it is necessary to reduce the heavy metal content before resourcing. More importantly, on the premise that the sludge meets the agricultural standards, a comprehensive ecological risk assessment is required to select a reasonable sludge recycling method.


Asunto(s)
Metales Pesados , Aguas del Alcantarillado , Animales , China , Ciudades , Monitoreo del Ambiente , Metales Pesados/análisis , Medición de Riesgo , Aguas del Alcantarillado/análisis , Suelo , Porcinos
15.
Huan Jing Ke Xue ; 42(3): 1477-1487, 2021 Mar 08.
Artículo en Chino | MEDLINE | ID: mdl-33742945

RESUMEN

Sulfate reduction with ammonium oxidation (SRAO) in laboratory ANAMMOX reactors was considered as an autotrophic process mediated by ANAMMOX bacteria (AnAOB), in which ammonium, as an electron donor, was oxidized by the electron acceptor sulfate. This process was developed based on the transformations of nitrogenous and sulfurous compounds observed in natural environments. Reported results vary widely for conversion mole ratios (ammonium/sulfate) as do intermediate and final products of the sulfate reduction. Thus, hypotheses surrounding biological conversion pathways of ammonium and sulfate in ANAMMOX consortia are implausible. In this study, continuous reactor experiments and batch tests were conducted under micro-aerobic (-100 mV < ORP < 0 mV, 0.5 mg·L-1 < DO < 1 mg·L-1), anoxic (-300 mV < ORP < -100 mV, 0.2 mg·L-1 < DO < 0.5 mg·L-1) and anaerobic (ORP < -300 mV, DO < 0.2 mg·L-1) conditions with different inoculated sludge (ANAMMOX sludge and mixed sludge) to verify the SRAO phenomena and identify possible pathways of substrate conversion. The key findings were that SRAO occurred only where SRB existed under anoxic condition, and was absent under anaerobic conditions with ANAMMOX consortia. The analysis of the microbial community and functional gene expression showed that ammonium oxidation by AAOB coupled with sequential ANAMMOX is possibly responsible for the loss of ammonium under anoxic condition. Organic substances released through microbial decay contributed to heterotrophic sulfate conversion by SRB. AnAOB do not possess the ability to oxidize ammonium with sulfate as the electron acceptor. SRAO could, in fact, involve a combination of aerobic ammonium oxidation, ANAMMOX, and heterotrophic sulfate reduction processes, which are mediated via AOB, AnAOB, and SRB.


Asunto(s)
Compuestos de Amonio , Anaerobiosis , Reactores Biológicos , Nitrógeno/análisis , Oxidación-Reducción , Aguas del Alcantarillado , Sulfatos
16.
Huan Jing Ke Xue ; 42(3): 1488-1495, 2021 Mar 08.
Artículo en Chino | MEDLINE | ID: mdl-33742946

RESUMEN

Wastewater treatment plants (WWTPs) have different treatment effects during different seasons due to changes in water quality and temperature. To understand bacterial community structure and diversity dynamics in the WWTPs, this study employed high-throughput sequencing technology during winter and summer. A total of 60 activated sludge samples were collected in five WWTPs in Beijing with different treatment processes in summer (temperature=28℃±2℃, water temperature=24.9℃±1.1℃) and winter (temperature=0℃±3℃, water temperature=16.8℃±1.3℃). The relative abundances of dominant bacterial genera in activated sludge varied significantly between the WWTPs but microbial community structure was typically similar between different treatment units (i.e., the anaerobic tank, anoxic tank, and aerobic tank) at each WWTP. At the same time, different bacteria dominated in winter and summer, when the relative abundance of SJA-15, Ferruginibacter, and Blasocatellaceae was 6.07%, 4.50%, and 4.44% respectively, when the relative abundance of Nitrospira, Methylotenera, and RBG-13-54-9 in winter was 10.17%, 3.96%, and 3.28%, respectively. Correlation analysis showed that temperature, total nitrogen (TN), NH4+-N, total phosphorus (TP), and chemical oxygen demand (COD) were the main environmental factors affecting microbial community structure, of which temperature had the greatest effect on species composition followed by TN. Furthermore, a predictive analysis of functional enzymes indicated that the abundance of key enzymes involved in the nitrogen cycle in the activated sludge of WWTPs is higher in winter than that in summer. These results show that temperature, water quality, and treatment process affect bacterial community structure (i.e., dominance and abundance) in WWTP activated sludge.


Asunto(s)
Microbiota , Purificación del Agua , Beijing , Estaciones del Año , Aguas del Alcantarillado , Eliminación de Residuos Líquidos , Aguas Residuales
17.
Sci Total Environ ; 764: 142917, 2021 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-33757240

RESUMEN

A full-scale sewage treatment plant in Xi'an city is discovered as the first mainstream anaerobic ammonia oxidation (anammox) treatment process in China. Whether its biological mechanism is the nitritation-anammox or partial denitrification (PD)-anammox brought violent controversy between two groups. As a third party, here we uncovered the mystery of the moving-bed biofilm reactor (MBBR) as a PD-anammox process by analyzing the diversity and phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) of microbes in anoxic pond. Anammox bacteria was found in the MBBR anoxic tank, which abundance is 8.9 times of that in the common anaerobic-anoxic-oxic process, confirming the existence of anammox process. The denitrifying bacteria (DNB) content in the anoxic tank is 5.9 times of the content of ammonia oxidizing bacteria (AOB), thus the DNB-anammox system is proved at the microbial composition level. The PICRUSt analysis found that ammonium nitrogen is mainly derived from the deamination of urea. The functional genes NAR and AMO of DNB and AOB are 910.84 and 5.80 rpms, respectively. The NAR gene content is 157.0 times of the AMO gene content and it is proved at the genetic level that the nitrite in the anoxic pool is mainly derived from denitrification. This study demonstrated the feasibility and advantages of the PD-anammox in the anammox process, which is different from the traditional nitritation-anammox demonstrated in Strass Wastewater Treatment Plant, Austria and Changi Water Reclamation Plant, Singapore and provided an alternative option for the mainstream application of anammox.


Asunto(s)
Compuestos de Amonio , Desnitrificación , Anaerobiosis , Austria , Biopelículas , Reactores Biológicos , China , Nitrógeno , Oxidación-Reducción , Filogenia , Aguas del Alcantarillado , Singapur , Aguas Residuales/análisis
18.
Sci Total Environ ; 764: 142907, 2021 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-33757248

RESUMEN

Antibiotics are continuously released into aquatic environments and ecosystems where they accumulate, which increases risks from the transmission of antibiotic resistance genes (ARGs). However, it is difficult to completely remove antibiotics by conventional biological methods, and during such treatment, ARGs may spread via the activated sludge process. Easy-to-biodegrade food have been reported to improve the removal of toxic pollutants, and therefore, this study investigated whether such co-substrates may also decrease the abundance of ARGs and their transferal. This study investigated amoxicillin (AMO) degradation using 0-100 mg/L acetate sodium as co-substrate in a sequencing biological reactor. Proteobacteria, Bacteroidetes, and Actinobacteria were identified as dominant phyla for AMO removal and mineralization. Furthermore, acetate addition increased the abundances of adeF and mdsC as efflux resistance genes, which improved microbial resistance, the coping ability of AMO toxicity, and the repair of the damage from AMO. As a result, acetate addition contributed to almost 100% AMO removal and stabilized the chemical oxygen demand (~20 mg/L) in effluents when the influent AMO fluctuated from 20 to 100 mg/L. Moreover, the total abundance of ARGs decreased by approximately ~30%, and the proportion of the most dominant antibiotic resistance bacteria Proteobacteria decreased by ~9%. The total abundance of plasmids that encode ARGs decreased by as much as ~30%, implying that the ARG spreading risks were alleviated. In summary, easy-to-biodegrade food contributed to the simultaneous elimination of antibiotics and ARGs in an activated sludge process.


Asunto(s)
Antibacterianos , Aguas del Alcantarillado , Amoxicilina , Antibacterianos/farmacología , Farmacorresistencia Microbiana/genética , Ecosistema , Genes Bacterianos , Aguas Residuales
19.
Chemosphere ; 270: 128632, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33757272

RESUMEN

Landscaping of municipal sludge is a good choice to solve the sludge disposal problem, and EDTA treatment can effectively promote the uptake of heavy metals (HMs) by plants, but the heavy metal leaching process and its main control factors are still poorly understood during the sludge landscaping disposal. In this study, the migration behavior of HMs in artificial soil made from municipal sludge compost (MSC) were investigated using soil column experiments. After six leaching events for a total of one year's rainfall, the average reduction percentage of total phosphorus, total nitrogen, organic matter in the MSC artificial soil were 13.4%, 10.1%, and 7.8%, respectively, while those of copper, lead, zinc, cadmium, nickel were 12.9%, 8.37%, 11.5%, 5.94%, and 10.7%, respectively. Treating ethylenediaminetetraacetic acid (EDTA) to the MSC artificial soil further enhanced the leach index of HMs to different degrees. HM concentration in leachate were increased with peak times postponed. Though EDTA treatment increased HM concentrations in subsoil, it did not change their water washing efficiency. The retention of HMs in subsoil was related to properties of local soil and its interaction with leachate. The potential ecological risk was of quite strong risk category in the MSC artificial soil and rapidly decreased from moderate to slight risk in subsoil. Cadmium was the main contribution accounting for 46%-93% of ecological risk. For landscaping applications, the composition of MSC artificial soil and local soil, as well as the capacity of the surrounding water, needs to be considered.


Asunto(s)
Compostaje , Metales Pesados , Contaminantes del Suelo , Metales Pesados/análisis , Aguas del Alcantarillado , Suelo , Contaminantes del Suelo/análisis
20.
Molecules ; 26(4)2021 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-33672924

RESUMEN

Presently, water quantity and quality problems persist both in developed and developing countries, and concerns have been raised about the presence of emerging pollutants (EPs) in water. The circular economy provides ways of achieving sustainable resource management that can be implemented in the water sector, such as the reuse of drinking water treatment sludges (WTSs). This study evaluated the potential of WTS containing a high concentration of activated carbon for the removal of two EPs: the steroid hormones 17ß-estradiol (E2) and 17α-ethinylestradiol (EE2). To this end, WTSs from two Portuguese water treatment plants (WTPs) were characterised and tested for their hormone adsorbance potential. Both WTSs showed a promising adsorption potential for the two hormones studied due to their textural and chemical properties. For WTS1, the final concentration for both hormones was lower than the limit of quantification (LOQ). As for WTS2, the results for E2 removal were similar to WTS1, although for EE2, the removal efficiency was lower (around 50%). The overall results indicate that this method may lead to new ways of using this erstwhile residue as a possible adsorbent material for the removal of several EPs present in wastewaters or other matrixes, and as such contributing to the achievement of Sustainable Development Goals (SDG) targets.


Asunto(s)
Aguas del Alcantarillado/química , Contaminantes Químicos del Agua/aislamiento & purificación , Purificación del Agua , Elementos , Concentración de Iones de Hidrógeno , Minerales/análisis , Termogravimetría
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