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1.
Chemosphere ; 254: 126898, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957293

RESUMO

The utilization of Microcystis biomass is an urgent issue in the mitigation of cyanobacterial bloom. In this study, Microcystis-derived biochar (MB) and Fe3O4-modified biochar (Fe3O4/MB) were fabricated for the U(VI) elimination. The results showed that U(VI) sorption process by either MB or Fe3O4/MB was pH-dependent and ionic strength-independent. The maximum sorption capacity of MB was higher than that of Fe3O4/MB. According to the analysis of X-ray photoelectron spectroscopy, U(VI) sorption on both MB and Fe3O4/MB was mainly ascribed to the surface complexation between U(VI) and oxygen-containing functional groups on the surface of MB. Fe3O4 particles on the surface of MB didn't provide extra active sites for the sorption of U(VI), but it enabled the adsorbent to be magnetically separated. Five consecutive sorption/desorption cycles verified the good reusability of Fe3O4/MB in this study. Therefore, the investigation is not only meaningful for the utilization of nuisance biomass from cyanobacterial blooms, but also provides novel adsorbents for the U(VI) removal from aqueous solutions.


Assuntos
Carvão Vegetal/química , Eutrofização , Óxido Ferroso-Férrico/química , Microcystis/química , Urânio/análise , Poluentes Radioativos da Água/análise , Purificação da Água/métodos , Adsorção , Biomassa , Concentração de Íons de Hidrogênio , Fenômenos Magnéticos , Modelos Teóricos , Concentração Osmolar
2.
Chemosphere ; 254: 126899, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957294

RESUMO

In this study, the reduction of iron-carbon internal electrolysis was reinforced by persulfate for p-nitrophenol removal. The effects of persulfate dosage, initial pH and iron-carbon mass ratio were comprehensively studied in batch experiments. In the system of iron-carbon internal electrolysis coupled with persulfate, the iron-carbon internal electrolysis and persulfate had a significant mutual influence, exhibiting a wide range of pH in the treatment process. Moreover, the coupled system also showed the remarkable removal and degradation efficiency of p-nitrophenol according to the contrast experiments. The satisfactory results should be attributed to the potential reduction of iron-carbon internal electrolysis, which was stimulated by persulfate to transform the nitro group to the amine group, accompanying the subsequent oxidation. Furthermore, persulfate possessed the ability that the dynamically destructive effect on external and internal of Fe0 and the scavenging action on activated carbon, effectively strengthening the potential energy for release and transfer of reductive substances. Both HO• and SO4•- as the main free radicals were formed to mineralize the intermediates in the coupled system. These findings indicate that the system of iron-carbon internal electrolysis coupled with persulfate can be a promising strategy for the treatment of the toxic and refractory wastewater.


Assuntos
Carvão Vegetal/química , Eletrólise/métodos , Ferro/química , Nitrofenóis/análise , Sulfatos/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Modelos Teóricos , Nitrofenóis/química , Oxirredução , Águas Residuárias/química , Poluentes Químicos da Água/química
3.
Chemosphere ; 254: 126903, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957296

RESUMO

We used discarded oyster shells to prepare vaterite calcium carbonate microparticles and explored the removal effects and the underlying mechanism toward several heavy metal ions. The removal efficiency for each ion type was: Pb2+ (99.9%), Cr3+ (99.5%), Fe3+ (99.3%), and Cu2+ (57.1%). With the exception of Cu2+, vaterite calcium carbonate particles exhibited excellent removal performance on all tested heavy metal ions, with exceptional results for Pb2+. The factor affecting the removal efficiency of heavy metal ions is shown to involve an ion exchange reaction between calcium and the heavy metal ions resulting in recrystallization. Vaterite calcium carbonate particles prepared by this method have the advantage of low price, easy synthesis, and reduction of environmental waste. Thus, this procedure for synthesizing vaterite CaCO3 provides an environmentally responsible method for preparing materials that can be economically incorporated into common consumer products such as household drinking water filtration systems.


Assuntos
Exoesqueleto/química , Carbonato de Cálcio/química , Metais Pesados/análise , Ostreidae , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Adsorção , Animais , Concentração de Íons de Hidrogênio , Troca Iônica , Íons , Microesferas , Propriedades de Superfície
4.
Chemosphere ; 254: 126926, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957303

RESUMO

In less than a decade, bioelectrochemical systems/microbial fuel cell integrated constructed wetlands (electroactive wetlands) have gained a considerable amount of attention due to enhanced wastewater treatment and electricity generation. The enhancement in treatment has majorly emanated from the electron transfer or flow, particularly in anaerobic regions. However, the chemistry associated with electron transfer is complex to understand in electroactive wetlands. The electroactive wetlands accommodate diverse microbial community in which each microbe set their own potential to further participate in electron transfer. The conductive materials/electrodes in electroactive wetlands also contain some potential, due to which, several conflicts occur between microbes and electrode, and results in inadequate electron transfer or involvement of some other reaction mechanisms. Still, there is a considerable research gap in understanding of electron transfer between electrode-anode and cathode in electroactive wetlands. Additionally, the interaction of microbes with the electrodes and understanding of mass transfer is also essential to further understand the electron recovery. This review mainly deals with the electron transfer mechanism and its role in pollutant removal and electricity generation in electroactive wetlands.


Assuntos
Fontes de Energia Bioelétrica , Eletricidade , Transporte de Elétrons , Águas Residuárias , Purificação da Água/métodos , Áreas Alagadas , Eletrodos , Microbiota , Águas Residuárias/análise , Águas Residuárias/microbiologia
5.
Aquat Toxicol ; 227: 105595, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32911330

RESUMO

In order to understand the potential impacts of nickel nanowires (Ni NWs) after reaching the aquatic environment, this research evaluated the toxicity of Ni NWs with different lengths (≤ 1.1, ≤11 and ≤ 80 µm) for several floating, planktonic and nektonic freshwater organisms. In this work, Ni NWs were synthesized by electrodeposition using anodized aluminum oxide (AAO) membranes. The toxicity of the NWs was assessed using a battery of aquatic species representative of key functions at the ecosystem level: the bacterium Aliivibrio fischeri, the algae Raphidocelis subcapitata, the macrophyte Lemna minor, the crustacean Daphnia magna and the zebrafish Danio rerio. Results indicated that for the concentrations tested (up to 2.5 mg L-1) the synthesized Ni NWs showed low toxicity. And although no lethal toxicity was observed for D. magna, at a sublethal level the feeding activity of the freshwater cladoceran was severely affected after exposure to Ni NWs. These findings showed that NWs can be accumulated in the gut of D. magna, even during a short exposure (24 h) directly impairing Daphnia nutrition and eventually populations growth. Consequently, this can also contribute to trophic transfer of NWs along the food chain. According to our results the toxicity of Ni NW may be mainly attributed to physical effects rather than chemical effects of Ni ions, considering that the concentrations of Ni NWs tested in this study were well below the toxicity thresholds reported in the literature for Ni ions and for Ni NMs.


Assuntos
Organismos Aquáticos/efeitos dos fármacos , Nanofios/toxicidade , Níquel/toxicidade , Purificação da Água/métodos , Aliivibrio fischeri , Animais , Clorofíceas , Daphnia/efeitos dos fármacos , Ecossistema , Cadeia Alimentar , Água Doce , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/toxicidade , Peixe-Zebra
6.
ACS Chem Neurosci ; 11(19): 2903-2905, 2020 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-32945160

RESUMO

Several lines of evidence suggest the presence of severe acute respiratory coronavirus-2 (SARS-CoV-2) in wastewater. The use of sewage water for irrigation is common in many developing countries, and it is only partially treated in the majority of countries with less than 10% of collected wastewater receiving any form of treatment globally. Wastewater is unsafe for human and animal consumption and contains impurities and microbial pathogens. Here, we pose the question of whether the reuse of untreated or partially treated wastewater for irrigation can expose susceptible populations and pets, leading to COVID-19 disease recurrence in the community? It is imperative to study the ecological relationships between humans, animals, and environmental health in relation to COVID-19 to contribute to a "One Health Concept" to design preventative strategies and attain optimal health for people, animals, and the environment.


Assuntos
Irrigação Agrícola/métodos , Infecções por Coronavirus/transmissão , Pneumonia Viral/transmissão , Águas Residuárias/virologia , Animais , Animais Domésticos/virologia , Betacoronavirus , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/veterinária , Humanos , Pandemias/veterinária , Pneumonia Viral/epidemiologia , Pneumonia Viral/veterinária , Fatores de Risco , Esgotos/virologia , Purificação da Água/métodos
7.
ACS Chem Neurosci ; 11(18): 2786-2788, 2020 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-32870651

RESUMO

Herein, we propose the use of novel adsorbents, namely micelle clay complexes comprising the clay montmorillonite, coupled with activated carbon for effective eradication of neuropathogenic microbes such as SARS-CoV-2 and Naegleria fowleri from water supplies for ablution/nasal irrigation. These can be incorporated easily to water collection devices, i.e., taps and water bottles, in the domestic setting. These filters are low cost, easy to install, and ideal disinfection systems. Such strategies are particularly useful for communities who have lack of access to safe water supplies, rely heavily on water storage tanks, or lack adequate water sanitation facilities, especially in developing countries.


Assuntos
Infecções por Coronavirus/prevenção & controle , Filtração/métodos , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Purificação da Água/métodos , Bentonita , Betacoronavirus , Infecções Protozoárias do Sistema Nervoso Central/prevenção & controle , Carvão Vegetal , Argila , Filtração/instrumentação , Humanos , Naegleria fowleri , Lavagem Nasal , Purificação da Água/instrumentação
8.
Ecotoxicol Environ Saf ; 205: 111343, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32979801

RESUMO

Taste and odor (T&O) problem in water is one of the main obstacles to improve the quality of drinking water, and efficient water treatment processes are urgently needed to control T&O compounds. Ultraviolet-mediated peroxymonosulfate (UV/PMS) diminution of trichloroanisole (TCA) in water was investigated in this paper. The treatment of 2,3,6-trichloroanisole (2,3,6-TCA) by three advanced oxidation processes (UV, UV/H2O2 and UV/PMS) was compared, and UV/PMS stood out. SO4•- and HO• were produced in the UV/PMS, and their specific contributions to 2,3,6-TCA oxidation were investigated. The competitive kinetic model was applied to determine the second-order reaction rate between 2,3,6-TCA and SO4•- or HO•. The products of 2,3,6-TCA generated in UV/PMS were analyzed with gas chromatography/high resolution-mass spectrometry (GC/HR-MS), and the degradation mechanism was proposed. The effects of water matrices (chloride, bicarbonate and humic acid) on UV/PMS performance were studied, and the decontamination of 2,3,6-TCA in real water was carried out. The disinfection byproducts (DBPs) alteration from 2,3,6-TCA by UV/PMS - chlorination treatment was explored. Overall, UV/PMS can effectively deal with the T&O pollution of TCA in water.


Assuntos
Anisóis/química , Peróxidos/química , Poluentes Químicos da Água/química , Cloro/análise , Desinfecção , Halogenação , Substâncias Húmicas/análise , Peróxido de Hidrogênio/química , Cinética , Oxirredução , Raios Ultravioleta , Água , Poluentes Químicos da Água/análise , Purificação da Água/métodos
9.
Ecotoxicol Environ Saf ; 205: 111330, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32977288

RESUMO

Constructed wetland has attracted more and more attention for wastewater purification due to its low construction cost and convenient operation recently. However, the unique waterflooding structure of constructed wetland makes the low dissolved oxygen level, which limits the effect of nitrogen removal in the system. Therefore, it is necessary to develop the oxygen-increasing technology to overcome the drawback in constructed wetlands. In this review, the mechanism of nitrogen removal in constructed wetland is discussed and oxygen is main influence factor is concluded. In addition, oxygen-increasing technologies in recent advances which improve the nitrogen removal efficiency greatly, are emphatically introduced. Finally, some future perspectives about oxygen-increasing techniques are also put forward in order to provide reference for further research and engineering application.


Assuntos
Nitrogênio/análise , Oxigênio/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Áreas Alagadas , Análise da Demanda Biológica de Oxigênio , Desnitrificação , Águas Residuárias/química
10.
Chemosphere ; 254: 126890, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957290

RESUMO

Chlorine disinfection inactivates pathogens in drinking water, but meanwhile it causes the formation of halogenated disinfection byproducts (DBPs), which may induce adverse health effects. Humans are unavoidably exposed to halogenated DBPs via tap water ingestion. Boiling of tap water has been found to significantly reduce the concentrations of halogenated DBPs. In this study, we found that compared with boiling only, adding ascorbate (vitamin C) or carbonate (baking soda) to tap water and then boiling the water further reduced the level of total organic halogen (a collective parameter for all halogenated DBPs) by up to 36% or 28%, respectively. Adding ascorbate removed the chlorine residual in tap water and thus prevented the formation of more halogenated DBPs in the boiling process. Adding carbonate elevated pH of tap water and consequently enhanced the hydrolysis (dehalogenation) of halogenated DBPs or led to the formation of more trihalomethanes that might volatilize to air during the boiling process. The comparative developmental toxicity of the DBP mixtures in the water samples was also evaluated. The results showed that adding a tiny amount of sodium ascorbate or carbonate (2.5-5.0 mg/L) to tap water followed by boiling for 5 min reduced the developmental toxicity of tap water to a substantially lower level than boiling only. The addition of sodium ascorbate or carbonate to tap water in household could be realized by preparing them in tiny pills. This study suggests simple and effective methods to reduce the adverse effects of halogenated DBPs on humans through tap water ingestion.


Assuntos
Desinfetantes/toxicidade , Poluentes Químicos da Água/toxicidade , Ácido Ascórbico , Carbonatos , Cloro , Desinfetantes/análise , Desinfecção/métodos , Água Potável/química , Halogenação , Halogênios , Humanos , Trialometanos/análise , Volatilização , Poluentes Químicos da Água/análise , Purificação da Água/métodos
11.
Chemosphere ; 258: 127276, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32947657

RESUMO

It is crucial for water environment security to remove its p-arsanilic acid (p-ASA) efficiently. Namely, removing p-arsanilic acid from aqueous media through magnetic separation, has become a novel method of removing toxic pollutants from water. Batch adsorption experiments demonstrated a higher adsorption of lignin-based magnetic activated carbon (201.64 mg g-1) toward p-ASA. In addition, LMAC nanoparticles exhibited typical magnetism (35.63 emu g-1 of saturation magnetization) and could be easily separated from the aqueous solution. Meanwhile, the endothermic adsorption of p-ASA over LMAC could spontaneously proceed and be well described by the pseudo-first-order and pseudo-second-order model as well as the intra-particle diffusion model. Moreover, the mechanisms during p-ASA adsorption over LMAC included the electrostatic attraction, surface complexation, π-π stacking and hydrogen bonding interaction. Importantly, lignin-based magnetic activated carbon has high absorbability and preferable reusability in real water samples. Consequently, this paper provides insights into preparation of the lignin-based magnetic activated carbon may be potential adsorbents for the remediation of organoarsenic compounds.


Assuntos
Ácido Arsanílico/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção , Carvão Vegetal , Cinética , Lignina , Fenômenos Magnéticos , Magnetismo , Imãs , Água , Poluentes Químicos da Água/análise
12.
Chemosphere ; 258: 127393, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32947669

RESUMO

UV/chlorine and chlorination processes have drawn great interests of water treatment utilities for oxidation and disinfection purposes. This work proposed a restricted chlorine-dosing strategy for UV/chlorine and post-chlorination under different pH and UV irradiation conditions by comprehensively assessing the oxidation of natural organic matter (NOM), formation of 9 haloacetic acids (HAA9) and bromate, and alteration of toxicity. During UV/chlorine with restricted chlorine doses, the oxidation of NOM chromophores (i.e., ΔUVA254) showed an apparent dependence on cumulative exposures of free available chlorine (CTFAC); Meanwhile, HAA9 formation was determined by CTFAC values and could be linearly correlated with ΔUVA254 irrespective of pH and UV irradiation wavelength. Irradiated by 254 nm LP-Hg lamp, the faster chlorine photolysis produced relatively higher steady-state concentrations of Cl• and HO• species but resulted in lower CTFAC. Reducing CTFAC values by operation parameters (pH, UV wavelength and irradiation fluence) could mitigate HAA9 formation during UV/chlorine at a specific chlorine dose. Additionally, high bromide concentration and acidic pH promoted more bromo-HAAs formation, and the presence of NOM significantly suppressed bromate formation. Analogous to ozonation, the UV/chlorine pre-oxidation could reduce the HAA9 formation potentials during post-chlorination at mildly alkaline pH. The photobacterium bioassay further demonstrated that although the UV/chlorine treatment might have increased the acute toxicity, the post-chlorination treatment could polish the acute toxicity to the level of chlorination alone. These results suggest that with the restricted chlorine-dosing strategy, the trade-off between oxidation/disinfection efficiency and DBPs formation can be controlled by monitoring CTFAC and ΔUVA254 values during UV/chlorine treatment.


Assuntos
Purificação da Água/métodos , Bromatos , Brometos/efeitos da radiação , Cloro , Desinfecção , Halogenação , Concentração de Íons de Hidrogênio , Oxirredução , Fotólise , Raios Ultravioleta , Poluentes Químicos da Água/análise , Purificação da Água/normas
13.
Chemosphere ; 258: 127416, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32947674

RESUMO

The emergence of antibiotics as pollutants in the environment is one of the worldwide concerns because the bacterial strains generate a threat to the aquatic ecosystem and human health. In this study, an alkylated chitosan polyelectrolyte (ChA-PE) was used in conjunction with ultrafiltration membranes to remove three commonly used antibiotics, including amoxicillin (AMX), tetracycline (TET), and ciprofloxacin (CIP), in aqueous systems. The removal study considered diverse experimental variables through two methods: washing (pH, ionic strength, polymer ratio, and antibiotic concentration) and enrichment (maximum retention capacity). The retention percentage reached 80% at a pH of 11.0 at different polymer/antibiotic molar ratios. The ChA-PE presented irreversibly bound antibiotic interaction values of 0.51, 0.74, and 0.92 for CIP, AMX, and TET, respectively, at a pH of 11, showing that the polymer presents stronger permanent interactions with AMX and TET. On the other hand, the ChA-PE presented maximum retention capacity values of 185.6, 420.2, and 632.8 mg g-1 for CIP, AMX, and TET, respectively, in accordance with the association efficiency percentage values of 73.54, 87.08, and 93.83% for CIP, AMX, and TET, respectively.


Assuntos
Antibacterianos/análise , Polieletrólitos/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Amoxicilina , Quitosana , Ciprofloxacino , Ecossistema , Humanos , Polímeros , Tetraciclina , Ultrafiltração/métodos
14.
Chemosphere ; 254: 126827, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957271

RESUMO

Herein, ultrasonication (US)-assisted novel nanomaterial Ti3C2Tx MXene was utilized as a selective adsorbent for treatment of synthetic dyes in model wastewater. Two types of US frequencies, 28 and 580 kHz, were applied to disperse MXene to evaluate the feasibility of US-assisted MXene for wastewater treatment. The physico-chemical properties of MXene after US were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and zeta potential. According to FTIR and XPS, 28 kHz US-assisted MXene had a greater amount of oxygenated functional groups and dispersion compared to 580 kHz US-assisted and pristine MXene. Subsequently, US-assisted MXene was utilized as an adsorbent for the removal of positively charged methylene blue (MB) and negatively charged methyl orange. Both 28 and 580 kHz US-assisted MXene showed better adsorption performance for only MB compared to stirring-assisted MXene based on kinetics, isotherms, and several water chemistry factors including solution pH, temperature, ionic strength, and humic acid. Advantages of US-assisted MXene for water treatment are its fast kinetics at low dose and high selectivity for positively charged target compounds (i.e., MB). The main adsorption mechanism between MXene and MB was electrostatic interaction (attraction); however, physical properties (i.e., aggregation kinetics and hydrodynamic diameter), measured via dynamic light scattering, were also found to be critical factors in controlling the adsorption performance of the system. Lastly, US-assisted MXene exhibited a high regeneration property, based on 4th adsorption-desorption cycles.


Assuntos
Corantes/análise , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Adsorção , Compostos Azo , Corantes/química , Difusão Dinâmica da Luz , Cinética , Azul de Metileno/química , Espectroscopia de Infravermelho com Transformada de Fourier , Titânio/análise , Águas Residuárias/química
15.
Chemosphere ; 260: 127625, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32758776

RESUMO

Ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) are widely used in drinking water treatment and wastewater recycling. However, limited information was available regarding their performance in removing trihalomethanes (THMs). The present study investigated the effect of feed solution characteristics and membrane fouling on THM removal by UF/NF/RO membranes. The results indicated that THMs were poorly removed by UF membrane, and the removal was dominated by hydrophobic adsorption. In contrast, high removal of THMs was observed for NF/RO membranes, which was contributed by both size exclusion and hydrophobic adsorption. By comparing the adsorption of THMs on NF/RO membranes at different feed concentration, it was found that the role of hydrophobic adsorption was more important at lower feed concentration. The removal of THMs by UF/NF/RO membranes increased with increasing feed concentration, which can be ascribed to the enhanced diffusion at higher concentration gradient. With increasing ionic strength, THM removal was decreased significantly for UF membrane, but the removal by NF/RO membranes remained largely unchanged. By comparing THM removal by clean and fouled membranes, the effect of membrane fouling was examined. The removal of most THMs (except trichloromethane) decreased after fouling for UF membrane, whereas decreased removal was only observed for iodinated THMs for fouled NF/RO membranes.


Assuntos
Purificação da Água/métodos , Adsorção , Filtração , Halogenação , Interações Hidrofóbicas e Hidrofílicas , Membranas Artificiais , Concentração Osmolar , Osmose , Reciclagem , Trialometanos , Ultrafiltração/métodos , Águas Residuárias
16.
Chemosphere ; 260: 127630, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32758778

RESUMO

Biological treatment processes have the potential to remove organic micropollutants (OMPs) during water treatment. The OMP removal capacity of conventional drinking water treatment processes such as rapid sand filters (RSFs), however, has not been studied in detail. We investigated OMP removal and transformation product (TP) formation in seven full-scale RSFs all treating surface water, using high-resolution mass spectrometry based quantitative suspect and non-target screening (NTS). Additionally, we studied the microbial communities with 16S rRNA gene amplicon sequencing (NGS) in both influent and effluent waters as well as the filter medium, and integrated these data to comprehensively assess the processes that affect OMP removal. In the RSF influent, 9 to 30 of the 127 target OMPs were detected. The removal efficiencies ranged from 0 to 93%. A data-driven workflow was established to monitor TPs, based on the combination of NTS feature intensity profiles between influent and effluent samples and the prediction of biotic TPs. The workflow identified 10 TPs, including molecular structure. Microbial community composition analysis showed similar community composition in the influent and effluent of most RSFs, but different from the filter medium, implying that specific microorganisms proliferate in the RSFs. Some of these are able to perform typical processes in water treatment such as nitrification and iron oxidation. However, there was no clear relationship between OMP removal efficiency and microbial community composition. The innovative combination of quantitative analyses, NTS and NGS allowed to characterize real scale biological water treatments, emphasizing the potential of bio-stimulation applications in drinking water treatment.


Assuntos
Água Potável/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Bélgica , Compostos Férricos , Filtração/métodos , Microbiota , Países Baixos , Nitrificação , RNA Ribossômico 16S/genética , Areia
17.
Chemosphere ; 260: 127600, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32758769

RESUMO

Granules initiation and development is the backbone of aerobic granular sludge technology. Feed composition can notably affect initiation and development of aerobic granules, and yield aerobic granules with distinct microbial community, morphology and structure. This paper reports an unexpected formation of aerobic granules in an aspartic acid fed SBR under unfavorable hydrodynamic selection conditions. Detailed characteristics of these aerobic granules were investigated in terms of morphology, structure, bioactivity and EPS. The results showed that due to the absence of favorable hydrodynamic selection pressure, the formed aerobic granules had an irregular shape with a rough outline and loose internal structure, which was quite different from mature aerobic granules. Bacteria in these aerobic granules were mainly presented in the form of microcolony with calcium and ß-polysaccharides responsible for its mechanical stability. The high N/C ratio of aspartic acid enabled the enrichment of significant amount of nitrifiers within aerobic granules and thus resulted in high nitrification activity of these aerobic granules. The negatively charged and hydrophilic aspartic acid also induced the bacteria to secrete more exopolysaccharides for contributing to more neutral and hydrophilic surface of the aerobic granules, which was beneficial for aspartic acid capture. As a result, polysaccharides, rather than proteins, became the major components of EPS in these aerobic granules. This paper provides us a foundation to better understand the granulation potential of proteinaceous substrates that is frequently encountered in industrial wastewaters.


Assuntos
Ácido Aspártico/química , Reatores Biológicos/microbiologia , Esgotos/microbiologia , Purificação da Água/métodos , Aerobiose , Análise da Demanda Biológica de Oxigênio , China , Matriz Extracelular de Substâncias Poliméricas/química , Hidrodinâmica , Microbiota , Modelos Teóricos , Nitrificação , Proteobactérias/isolamento & purificação , Esgotos/química , Propriedades de Superfície , Águas Residuárias/química
18.
Chemosphere ; 260: 127591, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32758773

RESUMO

This study examines the organization and morphology of Bacillus globigii (BG) spores, a common surrogate for Bacillus anthracis, which were seeded and then recovered at various times from several points within a conventional, pilot-scale activated sludge system. Recovered BG spores were enumerated, microscopically examined, and tested for resistance to chemical (i.e. 5% H2O2 for 8 min), thermal (80 °C for 30 min), and ultraviolet light (8 W, 254 nm UV for 1 min) inactivation. Spores exposed to activated sludge germinated, sporulated, and exhibited unique multilayer clustering patterns and statistically significant changes (p < 0.005) in dimensional morphology. Spores collected in the later experimental stages (i.e., during weeks 6 and 7) were significantly more resistant (p ≤ 0.05) to inactivation than those collected on the first day of testing. These results have direct consequences for sludge treatment requirements at wastewater treatment plants that receive spore-containing waste streams.


Assuntos
Bacillus/fisiologia , Temperatura Alta , Peróxido de Hidrogênio/farmacologia , Esgotos/microbiologia , Esporos Bacterianos/isolamento & purificação , Raios Ultravioleta , Purificação da Água/métodos , Microscopia de Força Atômica , Microscopia de Contraste de Fase , Projetos Piloto , Esporos Bacterianos/efeitos dos fármacos , Esporos Bacterianos/efeitos da radiação , Esporos Bacterianos/ultraestrutura
19.
Ecotoxicol Environ Saf ; 204: 111073, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32755736

RESUMO

The high pH and salinity of textile wastewater is a major hindrance to azo dye decolorization. In this study, a mixed bacterial consortium ZW1 was enriched under saline (10% salinity) and alkaline (pH 10.0) conditions to decolorize Methanil Yellow G (MY-G). Consortium ZW1 was mainly composed of Halomonas (49.8%), Marinobacter (30.7%) and Clostridiisalibacter (19.2%). The effects of physicochemical factors were systematically investigated, along with the degradation pathway and metagenome analysis. The co-carbon source was found to be necessary, and the addition of yeast extract led to 93.3% decolorization of 100 mg/L MY-G within 16 h (compared with 1.12% for control). The optimum pH, salinity, temperature and initial dye concentration were 8.0, 5-10%, 40 °C and 100 mg/L, respectively. The typical dye-related degradation enzymes were most effective at 10% salinity. Consortium ZW1 was also able to differentially decolorize five other direct and acidic dyes in a short period. Phototoxicity tests revealed the detoxification of MY-G degradation products. Combining UV-vis, FTIR and GC-MS detection, the MY-G degradation pathway by consortium ZW1 was proposed. Furthermore, metagenomic approach was used to elucidate the functional potential of genes in MY-G biodegradation. These results signify the broad potential application of halo-alkaliphilic consortia in the bioremediation of dyeing wastewater.


Assuntos
Compostos Azo/toxicidade , Corantes/toxicidade , Metagenoma , Microbiota/efeitos dos fármacos , Águas Residuárias , Poluentes Químicos da Água/toxicidade , Purificação da Água/métodos , Compostos Azo/metabolismo , Biodegradação Ambiental , Carbono/metabolismo , Corantes/metabolismo , Microbiota/genética , Salinidade , Temperatura , Indústria Têxtil , Águas Residuárias/química , Águas Residuárias/microbiologia , Poluentes Químicos da Água/metabolismo
20.
J Water Health ; 18(4): 556-565, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32833681

RESUMO

Hepatitis E Virus (HEV) genotype 1 and 2 infect an estimated 20 million people each year, via the faecal-oral transmission route. An urban outbreak of HEV occurred in Am Timan, Chad, between September 2016 and April 2017. As part of the outbreak response, Médecins Sans Frontières and the Ministry of Health implemented water and hygiene interventions, including the chlorination of town water sources. We aimed to understand whether these water treatment activities had any impact on the number of HEV infections, using geospatial analysis of epidemiological and water treatment monitoring data. By conducting cluster analysis we investigated whether there were areas of particularly high and low infection risk during the outbreak and explored the reasons for this. We observed two high-risk spatial clusters of suspected cases and one high-risk cluster of confirmed cases. Our main finding was that confirmed HEV cases had a higher median number of days of exposure to unsafe water compared to suspected and non-confirmed cases (Kruskal-Wallis Chi Square: 15.5; p < 0.001). Our study confirms the mixed, but shifting, transmission routes during this outbreak. It also highlights the spatial and temporal analytical methods, which can be employed in future outbreaks to improve understanding of HEV transmission.


Assuntos
Vírus da Hepatite E , Hepatite E/epidemiologia , Purificação da Água/métodos , Chade/epidemiologia , Cidades , Surtos de Doenças , Halogenação , Água
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