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1.
Med Sci Monit ; 27: e928374, 2021 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-33388740

RESUMO

BACKGROUND Although influenza primarily affects the respiratory system, it can cause severe neurological complications, especially in younger children, but knowledge about the early indicators of acute necrotizing encephalopathy (ANE) is limited. The main purpose of this article is to summarize the clinical characteristics, diagnosis, and treatment of neurological complications of influenza in children, and to identify factors associated with ANE. MATERIAL AND METHODS This was a retrospective study of children with confirmed influenza with neurological complications treated between 01/2014 and 12/2019 at Guangzhou Women and Children's Medical Center. A receiver operating characteristics curve analysis was performed to determine the prognostic value of selected variables. RESULTS Sixty-three children with IAE (n=33) and ANE (n=30) were included. Compared with the IAE group, the ANE group showed higher proportions of fever and acute disturbance of consciousness, higher alanine aminotransferase, higher aspartate aminotransferase, higher creatinine kinase, higher procalcitonin, higher cerebrospinal fluid (CSF) protein, and lower CSF white blood cells (all P<0.05). The areas under the curve (AUCs) for procalcitonin and CSF proteins, used to differentiate IAE and ANE, were 0.790 and 0.736, respectively. The sensitivity and specificity of PCT >4.25 ng/ml to predict ANE were 73.3% and 100.0%, respectively. The sensitivity and specificity of CSF protein >0.48 g/L to predict ANE were 76.7% and 69.7%, respectively. Thirteen (43.3%) children with ANE and none with IAE died (P<0.0001). CONCLUSIONS High levels of CSF protein and serum procalcitonin might be used as early indicators for ANE. All children admitted with neurological findings, especially during the influenza season, should be evaluated for influenza-related neurological complications.

2.
Ecotoxicol Environ Saf ; 210: 111880, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33421721

RESUMO

The coal pyrolysis wastewater (CPW) contributed to aquatic environment contamination with amount of aromatic pollutants, and the research on joint toxicity of the mixture of aromatic compounds was vital for environmental protection. By using Tetrahymena thermophile as non-target organism, the joint toxicity of typical nonpolar narcotics and polar narcotics in CPW was investigated. The results demonstrated that the nonpolar narcotics exerted chronic and reversible toxicity by hydrophobicity-based membrane perturbation, while polar narcotics performed acute toxicity by irreversible damage of cells. As the most hydrophobic nonpolar narcotics, indole and naphthalene caused the highest joint toxicity in 24 h with the lowest EC50mix (24.93 mg/L). For phenolic compounds, the combination of p-cresol and p-nitrophenol also showed the top toxicity (EC50mix = 10.9 mg/L) with relation to high hydrophobicity, and the joint toxicity was obviously stronger and more acute than that of nonpolar narcotics. Furthermore, by studying the joint toxicity of nonpolar narcotics and polar narcotics, the hydrophobicity-based membrane perturbation was the first step of toxicity effects, and afterwards the acute toxicity induced by electrophilic polar substituents of phenols dominated joint toxicity afterwards. This toxicity investigation was critical for understanding universal and specific effects of CPW to aquatic organisms.


Assuntos
Carvão Mineral , Pirólise , Tetrahymena/efeitos dos fármacos , Águas Residuárias/toxicidade , Poluentes Químicos da Água/toxicidade , Indóis/toxicidade , Naftalenos/toxicidade , Entorpecentes/toxicidade , Fenóis/toxicidade
3.
Chemosphere ; 262: 127872, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32791370

RESUMO

Magnetite nanoparticles (Fe3O4 NPs) was firstly used to enhance pollutants removal during coal gasification wastewater (CGW) treatment in anaerobic digestion (AD) system. Bench-scale results revealed that 200 mg/L and 20-40 nm of Fe3O4 NPs addition resulted in a maximum removal capacity of total phenol (TPh) at a temperature of 36 °C and hydraulic retention time (HRT) of 36 h. Meanwhile, Fe3O4 NPs addition reduced the oxidation reduction potential (ORP) values and biological toxicity, and enhanced the stability of AD system. Pilot-scale results showed that the TPh and chemical oxygen demand (COD) removal efficiency (53% and 49%) were obtained with the optimal dosage of Fe3O4 NPs. Moreover, electron nanowires may be established with Fe3O4 NPs assisted to perform direct interspecies electron transfer (DIET) among Geobacter, Pseudomonas and Methanosaeta species, and finally enhanced the pollutants removal efficiency.


Assuntos
Resíduos Industriais , Nanopartículas de Magnetita/química , Indústria de Petróleo e Gás , Eliminação de Resíduos Líquidos/métodos , Anaerobiose , Análise da Demanda Biológica de Oxigênio , Reatores Biológicos , Carvão Mineral , Elétrons , Fenol , Fenóis , Pseudomonas , Águas Residuárias
4.
Med Sci Monit ; 26: e928835, 2020 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-33335084

RESUMO

BACKGROUND This study summarizes the characteristics of children screened for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and reports the case of 1 child who was diagnosed with SARS-CoV-2 infection in Guangzhou Women and Children's Medical Center and the cases of his family members. MATERIAL AND METHODS The medical records of 159 children who were admitted to our hospital from January 23 to March 20, 2020, were retrospectively analyzed. Samples from pharyngeal or/and anal swabs were subjected to reverse-transcription polymerase chain reaction (RT-PCR) testing for SARS-CoV-2 within 12 h of patient admission; a second RT-PCR test was done 24 h after the first test. RESULTS Of the 159 patients, 151 patients had epidemiological histories, 14 patients had cluster onset, and 8 patients had no epidemiological history but had symptoms similar to coronavirus disease 2019 (COVID-19). The most common symptom was fever (n=125), followed by respiratory and gastrointestinal symptoms. A 7-year-old boy in a cluster family from Wuhan was confirmed with asymptomatic SARS-CoV-2 infection with ground-glass opacity shadows on his lung computed tomography scan, and his swab RT-PCR test had not turned negative until day 19 of his hospitalization. In patients who did not test positive for SARS-CoV-2, influenza, respiratory syncytial virus, and adenovirus were observed. A total of 158 patients recovered, were discharged, and experienced no abnormalities during follow-up. CONCLUSIONS For SARS-CoV-2 nosocomial infections, taking a "standard prevention & contact isolation & droplet isolation & air isolation" strategy can prevent infection effectively. Children with clustered disease need close monitoring.


Assuntos
/diagnóstico , /epidemiologia , /métodos , Criança , Pré-Escolar , China/epidemiologia , Coronavirus/metabolismo , Coronavirus/patogenicidade , Infecção Hospitalar/epidemiologia , Feminino , Febre , Hospitalização , Hospitais , Humanos , Masculino , Registros Médicos , Alta do Paciente , Estudos Retrospectivos , /patogenicidade
5.
Artigo em Inglês | MEDLINE | ID: mdl-33129515

RESUMO

Sn-based metal oxides and composites have been widely investigated as candidate anodes for lithium-ion batteries. However, continuous capacity fade caused by serious volumetric expansion and crystal pulverization is often noticed during lithiation and alloying processes. In this study, we design a novel heterogeneous structural composite by constructing sandwich-structured graphene hollow spheres limited Mn2SnO4/SnO2 heterostructures (Mn2SnO4/SnO2@SG), of which infiltration of Mn source promotes the dissolution-redeposition of SnO2 in hollow-spherical graphene (SnO2@SG) and their in-situ transformation into Mn2SnO4; and the uniform distributed Mn2SnO4 and SnO2 nanoparticles are adjacent each other to form heterostructure within the sandwiched graphene hollow spheres. By comparing with the single metal oxide SnO2@SG material, the influence of the microstructure, chemical composition, element valence state and electrochemical properties of the heterostructured Mn2SnO4/SnO2@SG is investigated. The results show that the construction of Mn2SnO4/SnO2 heterostructure dramatically improves electronic/ionic transport kinetics and increases lithium storage reversibility, therefore leading to distinctly superior rate capability (823.8 mAh g-1 at 5 C) and cycling capacity. An ultra-high discharge capacity of 1180.4 mA h g-1 is maintained up to 100 cycles at 100 mA g-1. The promising electrochemical performances can be attributed to the sandwiched-structure hollow graphene spherical skeleton and the formation of unique Mn2SnO4/SnO2 heterostructures.

6.
Bioresour Technol ; 308: 123308, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32278997

RESUMO

Powdered activated carbon (PAC), lignite activated coke (LAC) and Fe-C carriers were applied to enhance CBFBRs to degrade targeted phenolics. In start-up stage, PAC and LAC equipped CBFBRs with higher environment adaptability and phenolic degradation capacity for phenol (>96%), p-cresol (>91%) and 3, 5-dimethylphenol (>84%) in comparison to Fe-C carrier. In recovery stage, the superior performance was also identified for CBFBRs in basis of PAC and LAC than Fe-C-based reactor. However, the Fe-C carrier assisted CBFBR with more stable degradation performance under impact loading. By comparing microbiomes, significantly enriched Brachymonas (54.80%-68.81%) in CBFBRs exerted primary role for phenolic degradation, and positively contributed to microbial network. Meanwhile, Geobacter in Fe-C-based reactor induced excellent impact resistance by enhancing interspecific electron transfer among microbes. Furthermore, the investigation on functional genes related to phenolic degradation revealed that anaerobic pathway accounted for demethylation procedure, while aerobic pathways dominated the phenolic ring-cleavage process.


Assuntos
Microbiota , Águas Residuárias , Reatores Biológicos , Carvão Mineral , Fenóis , Pirólise , Eliminação de Resíduos Líquidos
7.
Bioresour Technol ; 306: 123123, 2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-32179400

RESUMO

Mixotrophic nitrate removal in wastewater from coal pyrolysis was achieved in microbial electrolysis cell with iron anode (iron-MEC). The effect of voltage, iron anode and conductivity were investigated. The effluent TN concentration was 8.35 ± 1.94 mg/L in iron-MEC when the conductivity of the wastewater was adjusted to 3.97 ± 0.08 mS/cm, which was lower than that in no-treated reactor. The increase of current density, which was resulted from the elevation of conductivity, promoted the iron corrosion and Fe2+ ion generation. Therefore, more Fe2+ ion was utilized by nitrate reducing ferrous oxidation bacteria (NRFOB) used to reduce nitrate. The microbial community analysis demonstrated that NRFOB, including Acidovorax and Bradyrhizobium, possessed a higher abundance in iron-MEC. The enrichment of Geobacter in iron-MEC might imply that the part of Fe(III) produced by ferrous oxidation was reduced by Geobacter, which established an iron cycle. Moreover, the production of N2O was decreased by the formation of Fe2+ ion.

8.
Environ Sci Pollut Res Int ; 27(14): 17054-17062, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32146670

RESUMO

Magnetite nanoparticles (Fe3O4 NPs) were applied in an anaerobic semi-continuous tank reactor (ASTR) to investigate its effect on the anaerobic digestion (AD) of acetate synthetic wastewater. The Fe3O4 NPs corrosion could create a more favorable micro-environment to enhance the methanogens activity. The chemical oxygen demand (COD) removal efficiency and methane production in test (ASTRT) were 31.1% and 101.5% higher than those in control (ASTRC). With the addition of Fe3O4 NPs, the concentration of key coenzyme (F420 and M) increased from averagely 0.523 and 5.352 µmol/g-VSS to 0.956 and 9.267 µmol/g-VSS, and the content of soluble microbial products (SMPs) significantly increased. Additionally, the high-throughput 16S rRNA gene sequencing further confirmed that the percentage of hydrogen-utilizing methanogens (Methanolinea) was up to 62.6% of total archaeal sequences. Fe3O4 NPs addition would accelerate electrons transfer from acids oxidizers to syntrophic methanogenesis, further stimulate acids oxidizers to decompose acetate to H2/CO2, and finally facilitate more methane production.


Assuntos
Nanopartículas de Magnetita , Anaerobiose , Reatores Biológicos , Metano , RNA Ribossômico 16S , Águas Residuárias
9.
Chemosphere ; 250: 126150, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32088614

RESUMO

The pipe deposits from water distribution network are iron-wastes, which could be used as a catalyst of advanced oxidation processes (AOPs). This paper prepared one main composition (α-FeOOH) of pipe deposits and compared the difference of chloramphenicol (CAP) degradation by α-FeOOH-activated hydrogen peroxide/persulfate and α-FeOOH-activated hydrogen peroxide/peroxymonosulfate with hydroxylamine assistance. Several key affecting factors were investigated. The results revealed that the double-oxidant system has a synergy effect in CAP degradation process. The hydroxyl radicals were identified as the predominant radicals in two different degradation processes via electron paramagnetic resonance (EPR) technique. The possible degradation pathways and products were confirmed by liquid chromatography-mass spectrometry (LC-MS). This study provided a theoretic research for pollutant removal by taking full advantage of pipe deposits and advance the development of water quality security in water distribution network in future.


Assuntos
Cloranfenicol/química , Hidroxilamina/química , Poluentes Químicos da Água/química , Catálise , Cloranfenicol/análise , Compostos Férricos/química , Peróxido de Hidrogênio/química , Radical Hidroxila , Hidroxilamina/análise , Hidroxilaminas/química , Ferro/química , Compostos de Ferro , Minerais , Modelos Químicos , Oxidantes , Peróxidos , Poluentes Químicos da Água/análise
10.
Environ Technol ; 41(6): 797-807, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30096992

RESUMO

This study was undergone to investigate the adsorption characteristics of tetrachloroethylene (PCE) on water supply network growth ring. According to the chemical composition of real network growth ring, iron oxide mixture containing synthesized goethite and lepidocrocite was applied as simulated growth ring. The results demonstrate that competition could take place only between PCE and the co-present organic non-ionic compound, while inorganic salt had no discernible effect on PCE adsorption. A maximum adsorption capacity of 33.118 mg g-1 at equilibrium was achieved. By the non-linear regression method, the equilibrium adsorption data fitted well with the Freundlich isotherm model (R2 = 0.994), and the kinetic data obeyed pseudo-first order model (R2 = 0.985). Thermodynamic tests indicate the spontaneous and exothermic nature of adsorption process. In addition, no significant variation between the FTIR spectra of the iron oxide mixture before and after adsorption was observed, which verifies that hydrogen bonds between PCE and mineral mixture could be neglected. An overview of the experimental results leads to the conclusion that the adsorption of PCE onto the simulate growth ring was driven by dispersion and hydrophobic interactions. As a case study, this work will provide some information about water supply securit protection.


Assuntos
Tetracloroetileno , Poluentes Químicos da Água , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Compostos Orgânicos , Termodinâmica
11.
Bioresour Technol ; 281: 126-134, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30818263

RESUMO

This study illustrated synergistic degradation of phenolic compounds by LAC-AS process via the insight into succession of microbial community under selective pressure. The results demonstrated that high phenols exhibited toxicity pressure to single AS process by eliminating non-tolerate bacteria, inducing vicious circulation by intermediates (catechol, nitrate, etc.) accumulation. However, LAC exerted another selective pressure and facilitated positive bio-community succession of moving biological bed reactor (MBBR). Firstly, it created rich microenvironments for diverse bacteria and promoted resilient adsorption for phenols with the assistance of biodegradation. Secondly, LAC enriched facultative bacteria, which developed multiple degradation paths on phenols and nitrogen based on multifunctional genes, counteracting the toxicity pressure. Specifically, phenols were degraded by the combination of anaerobic hydrolysis and oxidation, while conventional and shortcut nitrification-denitrification (SND) and nitrogen fixation all participated in nitrogen removal, achieving high removal of COD (93.49%), Tph (93.74%), TN (92.20%) and NH4+-N (93.20%) under the highest phenols.


Assuntos
Microbiota , Fenóis/metabolismo , Esgotos , Águas Residuárias/química , Adsorção , Biofilmes , Carvão Mineral , Coque , Desnitrificação , Nitrificação , Pirólise , Esgotos/microbiologia , Eliminação de Resíduos Líquidos/métodos
12.
Water Sci Technol ; 80(8): 1512-1523, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31961814

RESUMO

A simultaneous nitrification and denitrification (SND) bioaugmention system with Pseudomonas sp. HJ3 inoculated was established to explore the potential of simultaneous phenol and nitrogen removal in coal gasification wastewater (CGW). When the concentration of influent chemical oxygen demand (COD) and total phenols (TPh) was 1,765.94 ± 27.43 mg/L and 289.55 ± 10.32 mg/L, the average removal efficiency of COD and TPh at the stable operating stage reached 64.07% ± 0.76% and 74.91% ± 0.33%, respectively. Meanwhile, the average removal efficiency of NH4+-N and total nitrogen (TN) reached 67.96% ± 0.17% and 57.95% ± 0.12%, respectively. The maximum SND efficiency reached 83.51%. Furthermore, SND bioaugmentation performed with good nitrification tolerance of phenol shock load and significantly reduced toxic inhibition of organisms. Additionally, the microbial community analysis indicated that Pseudomonas sp. HJ3 was the predominant bacterium in the SND bioaugmentation system. Moreover, the indigenous nitrogen removal bacteria such as Thauera, Acidovorax and Stenotrophomonas were enriched, which further enhanced the nitrogen removal in the SND bioaugmentation system. The results demonstrated the promising application of SND bioaugmentation for enhancing simultaneous phenol and nitrogen removal in CGW treatment.


Assuntos
Desnitrificação , Nitrificação , Reatores Biológicos , Carvão Mineral , Nitrogênio , Fenol , Pseudomonas , Eliminação de Resíduos Líquidos , Águas Residuárias
13.
Chemosphere ; 209: 319-327, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29933168

RESUMO

Ozonation of pyridine and indole was investigated both in aqueous solution and biologically pretreated coal gasification wastewater (BPCGW). Experimental results showed that the removal of indole was hardly affected by pH value. Direct reaction rate constant of ozone with pyridine increased from 0.18 M-1 s-1 (protonated pyridine) to 3.03 M-1 s-1 (molecular pyridine), and that with molecular indole was 8.6 × 105 M-1 s-1. Seven and five transformation intermediates were observed for pyridine and indole, respectively. Ozonation pathways were proposed as hydroxylation, opening and cleavage of the aromatic ring. It was found that ammonia nitrogen (NH3N) increased by 3.3 mg L-1 in ozone process, suggesting the broken of the CN bonds of pyridine, indole and other N-heterocyclic compounds. In terms of biochemical oxygen demand to chemical oxygen demand (BOD5/COD), toxicity and resazurin dehydrogenase activity (DHA), the biodegradability was improved after ozone treatment, indicating the possibility of ozone combined with biosystem for the treatment of BPCGW. The results of gas chromatograph and mass spectrometry (GC-MS) indicated that primary products during first 10 min might lead to the obstinate toxicity, which was further proved by US Environmental Protection Agency (US-EPA) test. This study would assist in obtaining a better understanding of the application of ozonation pretreatment in BPCGW.


Assuntos
Biodegradação Ambiental , Carvão Mineral/análise , Ozônio/química , Águas Residuárias/química , Poluentes Químicos da Água/química
14.
J Environ Manage ; 223: 306-313, 2018 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-29935445

RESUMO

The selective extraction and concentration of salt from coal gasification brine (CGB) by nanofiltration membranes is a promising technology to achieve near-zero liquid discharge of coal gasification wastewater. To investigate the feasibility of recovery of salts and the interaction of organic compounds, multivalent ions and monovalent ions on the rejection ratio, three nanofiltration membranes (OWNF1, NF270 and Desal-5 DK) with an 1812 spiral-wound module were used in crossflow filtration. The rejection mechanism was analyzed by comparing the rejection performance as a function of the operation pressure (increasing from 1.0 MPa to 2.5 MPa), the concentration (increasing from 10,000 mg/L to 25,000 mg/L) and pH values (increasing from 3.0 to 10.0). The concentrations of anions and cations were determined using an ion chromatographic analyzer and an inductively coupled plasma emission spectrometer, respectively. The results show that the rejection of sulfate and the chemical oxygen demand were higher than 92.12% and 78.84%, respectively, at appropriate operation, while negative rejection of chloride was observed in the CGB. The decreasing rejection of organic compounds was due to swelling of the membrane pore in high-concentration solutions. Meanwhile, the organic compounds weakened the negative charge of the membrane active layer, consequently decreasing the ion rejection. More than 85% of the sodium chloride could be recovered, indicating that this technology is suitable for resource recovery from CGB and near-zero liquid discharge of coal gasification industry.


Assuntos
Carvão Mineral , Purificação da Água , Filtração , Membranas Artificiais , Nanotecnologia , Sais
15.
Bioresour Technol ; 262: 302-309, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29738959

RESUMO

The up-flow anaerobic sludge blanket (UASB) system with graphene assisted was developed for coal gasification wastewater (CGW) treatment. Short-term results showed that optimal graphene addition (0.5 g/L) resulted in a more significant enhancement of methane production and chemical oxygen demand (COD) removal compared with that of the optimal activated carbon addition (10.0 g/L). Long-term results demonstrated that COD removal efficiency and methane production rate with graphene assisted achieved 64.7% and 180.5 mL/d, respectively. In addition, graphene could promote microbes accumulation and enzymes activity, resulting in higher extracellular polymeric substances (EPS) and coenzyme F420 concentrations. X-ray Diffraction (XRD) analysis indicated that chemical of graphene changed insignificantly during the experiment. Meanwhile, with graphene assisted, cells were attached together to form microbial aggregates to facilitate sludge granulation process. Furthermore, the enriched Geobacter and Pseudomonas might perform direct interspecies electron transfer (DIET) with Methanosaeta via biological electrical connection, enhancing the anaerobic degradation of CGW.


Assuntos
Reatores Biológicos , Carvão Mineral , Águas Residuárias , Anaerobiose , Grafite , Metano , Esgotos , Eliminação de Resíduos Líquidos
16.
Bioresour Technol ; 262: 65-73, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29698839

RESUMO

Mixotrophic denitrification coupled biological denitrification with iron and carbon micro-electrolysis (IC-ME) is a promising emerging bioprocess for nitrate removal of biologically enhanced treated coal gasification wastewater (BECGW) with low COD to nitrate ratio. TN removal efficiency in R1 with IC-ME assisted was 16.64% higher than R2 with scrap zero valent iron addition, 23.05% higher than R3 with active carbon assisted, 30.51% higher than R4 with only active sludge addition, 80.85% higher than R5 utilizing single IC-ME as control. Fe2+ generated from IC-ME decreased the production of N2O and enriched more Nitrate-reducing Fe(Ⅱ) oxidation bacteria (NRFOB) Acidovorax and Thiobacillus, which could convert nitrate to nitrogen gas. And the presence of Fe3+, as the Fe2+ oxidation product, could stimulate the growth of Fe(III)-reducing strain (FRB) that indicated by redundancy analysis. Microbial network analysis demonstrated FRB Geothrix had a co-occurrence relationship with other bacteria, revealing its dominant involvement in nitrate removal of BECGW.


Assuntos
Reatores Biológicos , Desnitrificação , Águas Residuárias , Carbono , Carvão Mineral , Eletrólise , Ferro , Nitratos
17.
Bioresour Technol ; 251: 303-310, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29289874

RESUMO

The aim of this work was to study an integration of micro-electrolysis with biological reactor (MEBR) for strengthening removal of phenolic compounds in coal gasification wastewater (CGW). The results indicated MEBR achieved high efficiencies in removal of COD and phenolic compounds as well as improvement of biodegradability of CGW under the micro-oxygen condition. The integrated MEBR process was more favorable to improvement of the structural stability of activated sludge and biodiversity of specific functional microbial communities. Especially, Shewanella and Pseudomonas were enriched to accelerate the extracellular electron transfer, finally facilitating the degradation of phenolic compounds. Moreover, MEBR process effectively relieved passivation of Fe-C filler surface and prolonged lifespan of Fe-C filler. Accordingly, the synergetic effect between iron-carbon micro-electrolysis (ICME) and biological action played a significant role in performance of the integrated process. Therefore, the integrated MEBR was a promising practical process for enhancing CGW treatment.


Assuntos
Reatores Biológicos , Carvão Mineral , Águas Residuárias , Eletrólise , Oxigênio , Eliminação de Resíduos Líquidos
18.
Bioresour Technol ; 245(Pt A): 786-793, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28926910

RESUMO

Three identical anoxic-aerobic membrane bioreactors (MBRs) were operated in parallel for 300 consecutive days for raw (R1), ozonated (R2) and catalytic ozonated (R3) biologically pretreated coal gasification wastewater (BPCGW) treatment. The results demonstrated that catalytic ozonation process (COP) applied asa pretreatment remarkably improved the performance of the unsatisfactory single MBR. The overall removal efficiencies of COD, NH3-N and TN in R3 were 92.7%, 95.6% and 80.6%, respectively. In addition, typical nitrogenous heterocyclic compounds (NHCs) of quinoline, pyridine and indole were completely removed in the integrated process. Moreover, COP could alter sludge properties and reshape microbial community structure, thus delaying the occurrence of membrane fouling. Finally, the total cost for this integrated process was estimated to be lower than that of single MBR. The results of this study suggest that COP is a good option to enhance pollutants removal and alleviate membrane fouling in the MBR for BPCGW treatment.


Assuntos
Reatores Biológicos , Carvão Mineral , Águas Residuárias , Compostos Heterocíclicos , Membranas Artificiais , Ozônio , Esgotos
19.
Bioresour Technol ; 244(Pt 1): 84-91, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28779678

RESUMO

Simultaneous nitrification and denitrification (SND) for treating coal gasification wastewater (CGW) was achieved successfully in a lab-scale sequencing batch biofilm reactor (SBBR) by oxygen-limited aeration. SND efficiency increased gradually with the concentration of dissolved oxygen (DO) decreased from 4.5mg/L to 0.35mg/L. The maximum SND efficiency of 81.23% was obtained at DO concentration of 0.35mg/L, and the corresponding removal efficiency of NH4+-N and TN reached 76.91% and 70.23%, respectively. Meanwhile, COD was removed significantly and toxic compounds were degraded into biodegradable substances, which relieved effectively the inhibition on nitrogen removal. The results indicated that oxygen-limited condition performed greater toxic compounds and nitrogen removal compared with the aerobic condition. Furthermore, the results of scanning electron microscopic (SEM) and microbial community structure confirmed robust biofilm formation provided a suitable anoxic micro-environment for co-existence of nitrifying and denitrifying bacteria and organics degradation bacteria in the reactor at oxygen-limited condition.


Assuntos
Biofilmes , Carvão Mineral , Desnitrificação , Águas Residuárias , Reatores Biológicos , Nitrificação , Nitrogênio , Oxigênio , Eliminação de Resíduos Líquidos
20.
J Inequal Appl ; 2017(1): 132, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28680235

RESUMO

Based on the Padé approximation method, in this paper we determine the coefficients [Formula: see text] and [Formula: see text] such that [Formula: see text] where [Formula: see text] is any given integer. Based on the obtained result, we establish a more accurate formula for approximating π, which refines some known results.

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