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1.
Environ Sci Technol ; 58(10): 4662-4669, 2024 Mar 12.
Artículo en Inglés | MEDLINE | ID: mdl-38422482

RESUMEN

Since the mass production and extensive use of chloroquine (CLQ) would lead to its inevitable discharge, wastewater treatment plants (WWTPs) might play a key role in the management of CLQ. Despite the reported functional versatility of ammonia-oxidizing bacteria (AOB) that mediate the first step for biological nitrogen removal at WWTP (i.e., partial nitrification), their potential capability to degrade CLQ remains to be discovered. Therefore, with the enriched partial nitrification sludge, a series of dedicated batch tests were performed in this study to verify the performance and mechanisms of CLQ biodegradation under the ammonium conditions of mainstream wastewater. The results showed that AOB could degrade CLQ in the presence of ammonium oxidation activity, but the capability was limited by the amount of partial nitrification sludge (∼1.1 mg/L at a mixed liquor volatile suspended solids concentration of 200 mg/L). CLQ and its biodegradation products were found to have no significant effect on the ammonium oxidation activity of AOB while the latter would promote N2O production through the AOB denitrification pathway, especially at relatively low DO levels (≤0.5 mg-O2/L). This study provided valuable insights into a more comprehensive assessment of the fate of CLQ in the context of wastewater treatment.


Asunto(s)
Amoníaco , Compuestos de Amonio , Amoníaco/metabolismo , Aguas del Alcantarillado/microbiología , Bacterias/metabolismo , Reactores Biológicos/microbiología , Oxidación-Reducción , Óxido Nitroso/análisis , Nitrificación , Compuestos de Amonio/metabolismo
2.
J Sep Sci ; 46(22): e2300482, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37727055

RESUMEN

Here, an imine-linked-based spherical covalent organic framework (COF) was prepared at room temperature. The as-synthesized spherical COF served as an adsorbent in dispersive solid-phase extraction (dSPE), by its virtue of great surface area (1542.68 m2 /g), regular distribution of pore size (2.95 nm), and excellent stability. Therefore, a simple and high-efficiency dispersive solid phase extraction method based on a spherical COF coupled with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was established to determine aryl organophosphate esters in biological samples. This approach displayed favorable linearity in the range of 10.0-1000.0 ng/L (r > 0.9989), a high signal enhancement factor (58.8-181.8 folds) with low limits of detection (0.3-3.3 ng/L). Moreover, it could effectively eliminate complex matrix interference to accurately extract seven aryl organophosphate esters from mouse serum and tissue samples with spiked recoveries of 82.0%-117.4%. The as-synthesized spherical COF has been successfully applied in sample preparation. The dSPE-HPLC-MS/MS method based on a spherical COF has potential application to study the pollutants' metabolism in vivo.


Asunto(s)
Estructuras Metalorgánicas , Espectrometría de Masas en Tándem , Animales , Ratones , Espectrometría de Masas en Tándem/métodos , Estructuras Metalorgánicas/química , Cromatografía Líquida de Alta Presión , Extracción en Fase Sólida/métodos , Adsorción , Límite de Detección
3.
Metab Eng ; 64: 122-133, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33577950

RESUMEN

Nicotinamide adenine dinucleotide (NAD+) is an essential coenzyme involved in numerous physiological processes. As an attractive product in the industrial field, NAD+ also plays an important role in oxidoreductase-catalyzed reactions, drug synthesis, and the treatment of diseases, such as dementia, diabetes, and vascular dysfunction. Currently, although the biotechnology to construct NAD+-overproducing strains has been developed, limited regulation and low productivity still hamper its use on large scales. Here, we describe multi-strategy metabolic engineering to address the NAD+-production bottleneck in E. coli. First, blocking the degradation pathway of NAD(H) increased the accumulation of NAD+ by 39%. Second, key enzymes involved in the Preiss-Handler pathway of NAD+ synthesis were overexpressed and led to a 221% increase in the NAD+ concentration. Third, the PRPP synthesis module and Preiss-Handler pathway were combined to strengthen the precursors supply, which resulted in enhancement of NAD+ content by 520%. Fourth, increasing the ATP content led to an increase in the concentration of NAD+ by 170%. Finally, with the combination of all above strategies, a strain with a high yield of NAD+ was constructed, with the intracellular NAD+ concentration reaching 26.9 µmol/g DCW, which was 834% that of the parent strain. This study presents an efficient design of an NAD+-producing strain through global regulation metabolic engineering.


Asunto(s)
Ingeniería Metabólica , NAD , Escherichia coli/genética , NAD/genética
4.
Environ Sci Technol ; 55(9): 6329-6339, 2021 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-33848140

RESUMEN

The potential coexistence and interaction of bromine and polyamide membranes during membrane-based water treatment prompts us to investigate the effect of bromine on membrane performance. For fully aromatic polyamide membrane NF90 exposed under a mild bromination condition (10 mg/L), bromine incorporation resulted in more negatively charged (-13 vs -25 mV) and hydrophobic (55.2 vs 58.9°) surfaces and narrower pore channels (0.3 vs 0.29 nm). The permeabilities of water and neutral solutes were reduced by 64 and 69-87%, respectively, which was attributed to the decreased effective pore radius and hydrophilicity. NaCl permeability was reduced by 90% as a synergistic result of enhanced size exclusion and charge repulsion. The further exposure (100 and 500 mg/L bromine) resulted in a more hydrophobic surface (61.7 and 65.5°) and the minor further reduction for water and solute permeabilities (1-9%). Compared with chlorine, the different incorporation efficiency and properties (e.g., atomic size, hydrophilicity) of bromine resulted in opposite trends and/or different degrees for the variation of physicochemical properties and filtration performance of membranes. The bromine incorporation, the shift and disappearance of three characteristic bands, and the increased O/N ratio and calcium content indicated the degradation pathways of N-bromination and bromination-promoted hydrolysis under mild bromination conditions (480 mg/L·h). The further ring-bromination occurred after severe bromine exposure (4800-24,000 mg/L·h). The semi-aromatic polyamide membrane NF270 underwent a similar but less significant deteriorated filtration performance compared with NF90, which requires a different explanation.


Asunto(s)
Nylons , Purificación del Agua , Bromo , Filtración , Membranas Artificiales
5.
Environ Sci Technol ; 54(17): 10964-10973, 2020 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-32786580

RESUMEN

As a promising technology for sustainable nitrogen removal from wastewater, the membrane-aerated biofilm reactors (MABRs) performing autotrophic deammonification are faced with the problem of unwanted production of nitrous oxide (N2O, a potent greenhouse gas). As a common tool to study N2O production from such an MABR, the traditional one-dimensional modeling approach fails to simulate the existence of longitudinal gradients in the reactor and therefore might render N2O production significantly deviated from reality. To this end, this work aims to study the influences of key longitudinal gradients (i.e., in oxygen, liquid-phase components, and biofilm thickness) on the N2O production from a typical MABR performing autotrophic deammonification by applying a modified version of a newly developed compartmental model. Through comparing the modeling results of different reactor configurations, this work reveals that the single impact of the longitudinal gradients studied on the N2O production from the MABR follows the order: oxygen (significant) > liquid-phase components (slight) > biofilm thickness (almost none). When multiple longitudinal gradients are present, they become correlated and would jointly influence the N2O production and nitrogen removal of the MABR. The results also show the need for multispot measurements to get an accurate representation of spatial biofilm features of the MABR configuration with the membrane lumen designed/operated as a plug flow reactor. While the traditional modeling approach is acceptable to evaluate the nitrogen removal in most cases, it might overestimate or underestimate the N2O production from the MABR with at least one of the longitudinal gradients in oxygen and liquid-phase components. For such an MABR, the longitudinal heterogeneity in biofilm thickness and the number of biofilm thickness classes to be included in the model would also make a difference to the simulation results, especially the N2O production. The work also proposes that under the studied conditions, proper design/operation of the MABR in consideration of longitudinal heterogeneity has the theoretical potential of reducing the N2O production by 77% without significantly compromising the nitrogen removal.


Asunto(s)
Reactores Biológicos , Óxido Nitroso , Biopelículas , Nitrógeno , Óxido Nitroso/análisis , Aguas Residuales
6.
Molecules ; 23(3)2018 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-29498692

RESUMEN

Magnetite (Fe3O4) is a ferromagnetic iron oxide of both Fe(II) and Fe(III), prepared by FeCl2 and FeCl3. XRD was used for the confirmation of Fe3O4. Via the modification of Tetraethyl orthosilicate (TEOS), (3-Aminopropyl)trimethoxysilane (APTMS), and Alginate (AA), Fe3O4@SiO2, Fe3O4@SiO2-NH2, and Fe3O4@SiO2-NH2-AA nanoparticles could be obtained, and IR and SEM were used for the characterizations. Alkaloid adsorption experiments exhibited that, as for Palmatine and Berberine, the most adsorption could be obtained at pH 8 when the adsorption time was 6 min. The adsorption percentage of Palmatine was 22.2%, and the adsorption percentage of Berberine was 23.6% at pH 8. Considering the effect of adsorption time on liquid phase system, the adsorption conditions of 8 min has been chosen when pH 7 was used. The adsorption percentage of Palmatine was 8.67%, and the adsorption percentage of Berberine was 7.25%. Considering the above conditions, pH 8 and the adsorption time of 8min could be chosen for further uses.


Asunto(s)
Alcaloides/aislamiento & purificación , Alcaloides de Berberina/aislamiento & purificación , Berberina/aislamiento & purificación , Óxido Ferrosoférrico/química , Nanopartículas de Magnetita/química , Adsorción , Alginatos/química , Ácido Glucurónico/química , Ácidos Hexurónicos/química , Concentración de Iones de Hidrógeno , Isocianatos/química , Nanopartículas de Magnetita/ultraestructura , Silanos/química , Propiedades de Superficie
7.
Phys Chem Chem Phys ; 19(11): 7844-7852, 2017 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-28262870

RESUMEN

Four different synthetic routes (co-precipitation, oxidation-precipitation, citric acid sol-gel and reversed microemulsion) are adopted to prepare barium modified Pd/CeO2-ZrO2 catalysts and their catalytic activity towards CO, HC and NOx conversions is studied. The surface and bulk properties of these catalysts are characterized via XRD, N2 adsorption, XPS, UV-Raman, H2-TPR, and in situ DRIFTS. The catalyst prepared via the co-precipitation method exhibits the optimum three-way catalytic behavior, which is mainly due to its superior redox ability, whereas the oxidation-precipitation synthesis renders the catalyst with the best homogeneity and thermal resistance. However, for the catalyst prepared via the sol-gel route, its worst NOx reduction capacity is verified by the scarce appearance of negatively charged Pd0-N[double bond, length as m-dash]Oδ- species, which is related to the faster dissociation of NO based on in situ DRIFTS, and the abundance of surface CO-Pd+ species reveals its unsatisfactory deep oxidizability of the HC reactant.

8.
Water Res ; 251: 121151, 2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-38246075

RESUMEN

The discovery of complete ammonium oxidation (comammox) has subverted the traditional perception of two-step nitrification, which plays a key role in achieving biological nitrogen removal from wastewater. Floccular sludge-based treatment technologies are being applied at the majority of wastewater treatment plants in service where detection of various abundances and activities of comammox bacteria have been reported. However, limited efforts have been made to enrich and subsequently characterize comammox bacteria in floccular sludge. To this end, a lab-scale sequencing batch reactor (SBR) in the step-feeding mode was applied in this work to enrich comammox bacteria through controlling appropriate operational conditions (dissolved oxygen of 0.5 ± 0.1 g-O2/m3, influent ammonium of 40 g-N/m3 and uncontrolled longer sludge retention time). After 215-d operation, comammox bacteria gradually gained competitive advantages over counterparts in the SBR with a stable nitrification efficiency of 92.2 ± 2.2 %: the relative abundance of Nitrospira reached 42.9 ± 1.3 %, which was 13 times higher than that of Nitrosomonas, and the amoA gene level of comammox bacteria increased to 7.7 ± 2.1 × 106 copies/g-biomass, nearly 50 times higher than that of conventional ammonium-oxidizing bacteria. The enrichment of comammox bacteria, especially Clade A Candidatus Nitrospira nitrosa, in the floccular sludge led to (i) apparent affinity constants for ammonium and oxygen of 3.296 ± 0.989 g-N/m3 and 0.110 ± 0.004 g-O2/m3, respectively, and (ii) significantly low N2O and NO production, with emission factors being 0.136 ± 0.026 % and 0.023 ± 0.013 %, respectively.


Asunto(s)
Compuestos de Amonio , Aguas del Alcantarillado , Aguas del Alcantarillado/microbiología , Amoníaco , Bacterias , Nitrificación , Oxidación-Reducción , Oxígeno , Filogenia , Archaea
9.
Water Res ; 257: 121739, 2024 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-38728778

RESUMEN

The coupling between anammox and nitrate/nitrite-dependent anaerobic methane oxidation (n-DAMO) has been considered a sustainable technology for nitrogen removal from sidestream wastewater and can be implemented in both membrane biofilm reactor (MBfR) and granular bioreactor. However, the potential influence of the accompanying hydrogen sulfide (H2S) in the anaerobic digestion (AD)-related methane-containing mixture on anammox/n-DAMO remains unknown. To fill this gap, this work first constructed a model incorporating the C/N/S-related bioprocesses and evaluated/calibrated/validated the model using experimental data. The model was then used to explore the impact of H2S on the MBfR and granular bioreactor designed to perform anammox/n-DAMO at practical levels (i.e., 0∼5% (v/v) and 0∼40 g/S m3, respectively). The simulation results indicated that H2S in inflow gas did not significantly affect the total nitrogen (TN) removal of the MBfR under all operational conditions studied in this work, thus lifting the concern about applying AD-produced biogas to power up anammox/n-DAMO in the MBfR. However, the presence of H2S in the influent would either compromise the treatment performance of the granular bioreactor at a relatively high influent NH4+-N/NO2--N ratio (e.g., >1.0) or lead to increased energy demand associated with TN removal at a relatively low influent NH4+-N/NO2--N ratio (e.g., <0.7). Such a negative effect of the influent H2S could not be attenuated by regulating the hydraulic residence time and should therefore be avoided when applying the granular bioreactor to perform anammox/n-DAMO in practice.


Asunto(s)
Reactores Biológicos , Sulfuro de Hidrógeno , Metano , Nitratos , Nitritos , Oxidación-Reducción , Sulfuro de Hidrógeno/metabolismo , Anaerobiosis , Metano/metabolismo , Nitratos/metabolismo , Eliminación de Residuos Líquidos/métodos , Nitrógeno/metabolismo , Aguas Residuales/química
10.
Materials (Basel) ; 16(14)2023 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-37512219

RESUMEN

Ionic liquid (IL) combined with graphene additives have garnered extensive attention in the field of high-performance lubricating materials. However, the ambiguous mechanism of graphene influencing the load-carrying and anti-wear capacity of ILs needs further study. In this work, friction simulation shows that adding graphene causes friction coefficient to reduce by up to 88% compared with pure ILs, but lubrication performance is lost due to the destruction of graphene under high stress. Meanwhile, multilayer graphene has better friction-reducing performance and friction durability as compared to the monolayer structure, which is attributed to the easy-shear property and the reduction in the percentage of high tensile stress sites in multilayer graphene structure. In addition, it was found that excessively thick ILs film would form a three-body abrasive wear structure with graphene, which accelerated the structural destruction of graphene and caused a decline in its tribological properties. It is believed these findings can be valuable for designing of high-performance lubricating oil for practical engineering.

11.
Front Plant Sci ; 14: 1297399, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38130486

RESUMEN

Introduction: Owing to challenges in the study of complex rhizosphere and endophytic microbial communities, the composition and function of such microbial communities in steppe ecosystems remain elusive. Here, we studied the microbial communities of the rhizosphere and endophytic microbes of the dominant plant species across the Inner Mongolian steppes using metagenomic sequencing and investigated their relationships with changes in mean annual temperature (MAT) and mean annual precipitation (MAP). Methods: Metagenomic sequencing based on Illumina high-throughput sequencing, using the paired end method to construct a small fragment library for sequencing. Results: Adaptation of root systems to the environment affected the composition and function of rhizosphere and endophytic microbial communities. However, these communities exhibited distinct community assembly and environmental adaptation patterns. Both rhizosphere and endophytic microbial communities can be divided into two unrelated systems based on their ecological niches. The composition and function of the rhizosphere microbial communities were mainly influenced by MAT, while those of the endophytic microbial communities were mainly influenced by MAP. MAT affected the growth, reproduction, and lipid decomposition of rhizosphere microorganisms, whereas MAP affected reverse transcription and cell wall/membrane/envelope biogenic functions of endophytic microorganisms. Conclusion: Our findings reveal the composition and function of the rhizosphere and endophytic microbial communities in response to changes in MAP and MAT, which has important implications for future biogeography and climate change research.

12.
Bioresour Technol ; 386: 129510, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37495161

RESUMEN

In this work, a bioprocess model was applied to first determine the impacts of influent substrates conditions on the granular bioreactor performing nitrate/nitrite-dependent anaerobic methane oxidation (n-DAMO) and anammox integrated processes and then investigate the roles of granular sludge properties in regulating the bioreactor performance and start-up process. The ideal influent substrates conditions were identified at NO2--N/NH4+-N of 1:1 and dissolved CH4 concentration of 85 g COD m-3, which achieved 98.6% total nitrogen removal and 87.7% dissolved CH4 utilization. Under such ideal influent conditions, the initial properties of granular sludge didn't significantly affect the granular bioreactor performance. However, inoculation of granular sludge with a relatively small granular sludge size and a high abundance of n-DAMO archaea or/and anammox bacteria could effectively shorten the bioreactor start-up. Meanwhile, reducing the diffusivity of solutes within granular sludge was also beneficial for expediting the start-up process and promoting dissolved CH4 utilization.


Asunto(s)
Compuestos de Amonio , Nitratos , Aguas del Alcantarillado , Nitritos , Anaerobiosis , Metano , Oxidación Anaeróbica del Amoníaco , Desnitrificación , Reactores Biológicos/microbiología , Oxidación-Reducción , Nitrógeno
13.
Chemosphere ; 311(Pt 1): 136849, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36252901

RESUMEN

The aerobic biotreatment process for the dual goals of antibiotic removal and ammonia retainment for the field-return-based treatment of swine wastewater was optimized by adding 2-chloro-6-trichloromethylpyridine (TCMP), commonly used as a nitrogen fertilizer synergist. The results show that the dosage of 5-10 mg/L TCMP daily effectively inhibited nitrification. The COD and tetracycline antibiotics (TCs) in the absence of TCMP was removed by 91% and 76%, and became 87% and 78% with 5 mg/L TCMP and 83% and 70% with 10 mg/L TCMP, respectively. The removal efficiency of four TCs generally followed a decreasing trend of chlortetracycline (CTC) > doxycycline (DC) > tetracycline (TC) > oxytetracycline (OTC). A dosage of 5 mg/L TCMP daily inhibited ammonia nitrification effectively and only slightly affected the removal of conventional organic pollutants and TCs. The contribution of volatilization and hydrolysis to the removal of TCs was negligible. The overall removal efficiency of four TCs in removal pathway experiments was 98%, 94%, 97%, and 96% for OTC, CTC, DC, and TC, of which 69%, 41%, 56%, and 62% was contributed by absorption, and 29%, 53%, 41%, and 34% was contributed by biodegradation, respectively. This study may have significant implications for the proper management of livestock wastewater intended to be used as fertilizers, which aims to reduce the exposure risk of antibiotics and preserve its nutrient value.


Asunto(s)
Clortetraciclina , Compuestos Heterocíclicos , Oxitetraciclina , Porcinos , Animales , Aguas Residuales , Nitrificación , Amoníaco , Tetraciclina/metabolismo , Antibacterianos , Doxiciclina
14.
Sci Total Environ ; 857(Pt 3): 159728, 2023 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-36302422

RESUMEN

Recently, the nitrate/nitrite-dependent anaerobic methane oxidation (n-DAMO) processes have become a research hotspot in the field of wastewater treatment. The n-DAMO processes could not only mitigate direct and indirect carbon emissions from wastewater treatment plants but also strengthen biological nitrogen removal. However, the applications of n-DAMO-based biotechnologies face practical difficulties mainly caused by the distinctive properties of n-DAMO microorganisms and the limited/availability of methane with poor solubility. In this sense, the choice of bioreactors will play important roles that influence the growth and functioning of n-DAMO microorganisms, thus enabling dedicated development of the n-DAMO processes and efficient applications of n-DAMO-based biotechnologies. Therefore, this paper aims to discuss the three commonly-applied types of bioreactors, covering the individual working principle and state-of-the-art removal performance of nitrogen as well as dissolved methane observed when adopted for n-DAMO-based biotechnologies. With noted limitations for each bioreactor type, several key perspectives were proposed which hopefully would inspire future investigation and practical applications of the n-DAMO processes.


Asunto(s)
Compuestos de Amonio , Metano , Aguas Residuales , Nitratos , Nitritos , Anaerobiosis , Desnitrificación , Reactores Biológicos , Nitrógeno , Oxidación-Reducción , Óxidos de Nitrógeno
15.
Sci Total Environ ; 859(Pt 1): 160285, 2023 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-36403844

RESUMEN

Efficient recovery of nitrous oxide (N2O) through heterotrophic denitrification with the help of Fe(II)EDTA-NO as a chelating agent has been regarded as an ideal technology to treat nitric oxide (NO)-rich flue gas. In this study, an integrated NO-based biological denitrification model was developed to describe the sequential reduction of the NO fixed in Fe(II)EDTA-NO with organic carbon as the electron donor. With the inclusion of only the key pathways contributing to nitrogen transformation, the model was firstly developed and then calibrated/validated and evaluated using the data of batch tests mediated by the identified functional heterotrophic bacteria at various substrates concentrations and then used to explore the possibility of enhancing N2O recovery by altering the substrates condition and reactor setup. The results demonstrated that the optimal COD/N ratio decreased consistently from 1.5 g-COD/g-N at the initial NO concentration of 40 g-N/m3 to 1.0 g-COD/g-N at the initial NO concentration of 420 g-N/m3. Furthermore, sufficiently increasing the headspace volume of the reactor was considered an ideal strategy to obtain ideal N2O production of 86.6 % under the studied conditions. The production of high-purity N2O (98 %) confirmed the practical application potential of this integrated treatment technology to recover a valuable energy resource from NO-rich flue gas.


Asunto(s)
Desnitrificación , Óxido Nítrico , Ácido Edético , Óxido Nitroso/metabolismo , Procesos Heterotróficos , Reactores Biológicos/microbiología
16.
Sci Total Environ ; 895: 165051, 2023 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-37391158

RESUMEN

The discovery of complete ammonium oxidation (comammox) has redefined the perception of the nitrification process which plays a vital part in biological nitrogen removal (BNR) from wastewater. Despite the reported detection or cultivation of comammox bacteria in biofilm or granular sludge reactors, limited attempts have been made to enrich or assess comammox bacteria in floccular sludge reactors with suspended growth of microbes, which are most extensively applied at wastewater treatment plants. Therefore, through making use of a comammox-inclusive bioprocess model reliably evaluated using batch experimental data with joint contributions of different nitrifying guilds, this work probed into the proliferation and functioning of comammox bacteria in two commonly-used floccular sludge reactor configurations, i.e., continuous stirred tank reactor (CSTR) and sequencing batch reactor (SBR), under mainstream conditions. The results indicated that compared with the studied SBR, the CSTR was observed to favor the enrichment of comammox bacteria through maintaining a sufficient sludge retention time (40-100 d) while avoiding an extremely low DO level (e.g., 0.05 g-O2/m3), irrespective of the varied influent NH4+-N of 10-100 g-N/m3. Meanwhile, the inoculum sludge was found to greatly influence the start-up process of the studied CSTR. By inoculating the CSTR with a sufficient amount of sludge, finally enriched floccular sludge with a high abundance of comammox bacteria (up to 70.5 %) could be rapidly obtained. These results not only benefitted further investigation and application of comammox-inclusive sustainable BNR technologies but also explained, to some extent, the discrepancy in the reported presence and abundance of comammox bacteria at wastewater treatment plants adopting floccular sludge-based BNR technologies.


Asunto(s)
Reactores Biológicos , Aguas del Alcantarillado , Aguas del Alcantarillado/microbiología , Reactores Biológicos/microbiología , Aguas Residuales , Nitrificación , Bacterias , Nitrógeno , Oxidación-Reducción , Amoníaco
17.
Sci Total Environ ; 835: 155411, 2022 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-35490813

RESUMEN

This work aimed to reflect the advancements in water-related science, technology, and policy and shed light on future research opportunities related to water through a systematic overview of Water Research articles published in the first 21.5 years of the 21st century. Specific bibliometric analyses were performed to i) reveal the temporal and spatial trends of water-related research themes and ii) identify the underlying connections between research topics. The results showed that while top topics including wastewater (treatment), drinking water, adsorption, model, biofilm, and bioremediation remained constantly researched, there were clear shifts in topics over the years, leading to the identification of trending-up and emerging research topics. Compared to the first decade of the 21st century, the second decade not only experienced significant uptrends of disinfection by-products, anaerobic digestion, membrane bioreactor, advanced oxidation processes, and pharmaceuticals but also witnessed the emerging popularity of PFAS, anammox, micropollutants, emerging contaminants, desalination, waste activated sludge, microbial community, forward osmosis, antibiotic resistance genes, resource recovery, and transformation products. On top of the temporal evolution, distinct spatial evolution existed in water-related research topics. Microplastics and Covid-19 causing global concerns were hot topics detected, while metagenomics and machine learning were two technical approaches emerging in recent years. These consistently popular, trending-up and emerging research topics would most likely attract continuous/increasing research input and therefore constitute a major part of the prospective water-related research publications.


Asunto(s)
Bibliometría , COVID-19 , Agua Potable , Humanos , Plásticos , Estudios Prospectivos , Aguas Residuales
18.
Bioresour Technol ; 349: 126887, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35202830

RESUMEN

While sulfur-driven autotrophic denitrification (SDAD) occurring in the anoxic reactor of the sulfate reduction, autotrophic denitrification and nitrification integrated (SANI) system has been regarded as the main nitrogen removal bioprocess, little is known about the accompanying Anammox bacteria whose presence is made possible by the co-existence of NH4+ and NO2-. Therefore, this work firstly developed an integrated SDAD-Anammox model to describe the interactions between sulfur-oxidizing bacteria and Anammox bacteria. The model was subsequently used to explore the impacts of influent conditions on the reactor performance and microbial community structure of the anoxic reactor. The results revealed that at a relatively low ratio of <1.5 mg S/mg N, Anammox bacteria could survive and even take a dominant position (up to 58.9%). Finally, a modified SANI system configuration based on the effective collaboration between SDAD and Anammox processes was proposed to improve the efficiency of the treatment of sulfate-rich saline sewage.


Asunto(s)
Reactores Biológicos , Desnitrificación , Oxidación Anaeróbica del Amoníaco , Procesos Autotróficos , Nitrógeno , Oxidación-Reducción , Aguas del Alcantarillado/microbiología , Azufre , Aguas Residuales/análisis
19.
Bioresour Technol ; 356: 127307, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35569712

RESUMEN

This work studied the impacts of key granule properties on the granular reactor performing partial nitritation/anammox from the modeling perspective. The results could guide not only future reliable modeling but also practical startup/operation of the reactor. To achieve high total nitrogen (TN) removal whilst avoiding significant N2O production, inoculated granules should be big and anammox-enriched. The optimum boundary layer thickness for maximum TN removal increased with the decreasing diffusivity of soluble components in the granule structure. Even though a thick boundary layer could protect anammox bacteria from elevated dissolved oxygen (DO) (e.g., 0.5 g-O2/m3) and obtain high TN removal (>90.0%) and low N2O production (<1.8%), even complete removal of the boundary layer would fail to provide sufficient substrate for anammox and therefore couldn't increase TN removal to 90.0% and decrease N2O production to <2.4% at insufficient DO (e.g., 0.3 g-O2/m3 in the presence of lifted influent NH4+ concentration).


Asunto(s)
Desnitrificación , Nitrógeno , Procesos Autotróficos , Reactores Biológicos/microbiología , Oxidación-Reducción , Aguas del Alcantarillado/microbiología
20.
Sci Total Environ ; 806(Pt 1): 150309, 2022 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-34562755

RESUMEN

An optimized aerobic-based treatment method that effectively removes antibiotics and retains ammonia is urgently needed for the field-return-based management of livestock wastewater. Allylthiourea (ATU, used for BOD determination), and 2-chloro-6-trichloromethylpyridine (TCMP) and 3,4-dimethylpyrazole phosphate (DMPP) (commonly used as nitrogen fertilizer synergists) were separately added to sequencing batch reactors (SBRs), in order to investigate their effect on nitrification inhibition and pollutant removal for livestock wastewater treatment. The laboratory test shows that the daily addition of 43.8 mg/L ATU or 17.5 mg/L TCMP to SBRs effectively inhibited nitrification. Nitrification inhibition by DMPP seemed fluctuated and insufficient even various dosing strategies were attempted. The removal efficiency of antibiotics was reduced from 95% to 85% with the addition of ATU, while not significantly influenced by TCMP and DMPP. The COD removal efficiency was reduced by only 6%-10% with the addition of three inhibitors. The pilot study shows that nitrification inhibition efficiency reached 89% with the daily addition of 11.5 mg/L TCMP. The total removal efficiency of antibiotics remained over 93%. The laboratory and pilot studies consistently demonstrate that TCMP played a satisfactory nitrification inhibition role and had a negligible effect on antibiotic removal. The current work provides a novel insight for the proper field-return-based management of livestock wastewater, which achieves the dual goals of reducing the risk of antibiotic exposure and preserving its nutrient value as fertilizers.


Asunto(s)
Nitrificación , Aguas Residuales , Animales , Antibacterianos , Reactores Biológicos , Desnitrificación , Ganado , Nitrógeno , Proyectos Piloto
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