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1.
Brain Inj ; 32(11): 1405-1412, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29985665

RESUMO

OBJECTIVE: Delayed neurological deficit was often observed in patients underwent craniectomy, which could be improved by cranioplasty. Little is known about hemodynamic improvement before and after cranioplasty. METHODS: Cerebral blood perfusion, tympanic membrane temperature (TMT), neuropsychological and cognitive function were assessed in eleven craniectomy patients before and after cranioplasty. RESULTS: Before cranioplasty, the cerebral blood volume (CBV) on the decompressed side was significantly lower than that of the contralateral side. The cranioplasty led to instant improvement (7 days after cranioplasty) of cerebral perfusion at the cranioplasty side in the frontal lobe, parietal lobe, temporal lobe, mesencephalon, basal ganglia and thalamus, but not the occipital lobe and epencephalon. Interestingly, CBV of the thalamus and basal ganglia gradually decreased to pre-surgical status 6 months later while the frontal lobe, parietal lobe, temporal lobe, mesencephalon remained well perfused. Meanwhile, the TMT changes acquired positive correlation with the perfusion of temporal lobe and mesencephalon as well as the GCS and MMSE score. CONCLUSION: The cranioplasty remarkably improves neurological and cognitive function by ameliorating cerebral perfusion in certain regions. The TMT could be used as a non-invasive method to monitor the cerebral perfusion improvement after the cranioplasty.


Assuntos
Temperatura Corporal/fisiologia , Circulação Cerebrovascular/fisiologia , Craniectomia Descompressiva/métodos , Membrana Timpânica/cirurgia , Lesões Encefálicas/cirurgia , Feminino , Seguimentos , Lateralidade Funcional , Escala de Resultado de Glasgow , Humanos , Masculino , Testes Neuropsicológicos , Resultado do Tratamento , Membrana Timpânica/fisiologia
2.
J Environ Sci (China) ; 67: 154-160, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29778148

RESUMO

Inexact mechanism of aerobic granulation still impedes optimization and application of aerobic granules. In this study, the extended Derjaguin, Landau, Verwey, and Overbeek (XDLVO) theory and physicochemical properties were combined to assess the aggregation ability of sludge during aerobic granulation process qualitatively and quantitatively. Results show that relative hydrophobicity of sludge and polysaccharide content of extracellular polymeric substances (EPS) increased, while electronegativity of sludge decreased during acclimation phase. After 20days' acclimation, small granules began to form due to high aggregation ability of sludge. Since then, coexisted flocs and granules possessed distinct physicochemical properties during granulation and maturation phase. The relative hydrophobicity decreased while electronegativity increased for flocs, whereas that for granules presented reverse trend. Through analyzing the interaction energy using the XDLVO theory, small granules tended to self-grow rather than self-aggregate or attach of flocs due to poor aggregation ability between flocs and granules during the granulation phase. Besides, remaining flocs were unlikely to self-aggregate owing to poor aggregation ability, low hydrophobicity and high electronegativity.


Assuntos
Esgotos/química , Eliminação de Resíduos Líquidos/métodos , Aerobiose , Reatores Biológicos , Floculação , Polímeros/química , Polissacarídeos/química
3.
Bioresour Technol ; 260: 61-67, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29614452

RESUMO

Recovery of volatile fatty acids (VFAs) from wastewater is an important route for wastewater valorization. Selective acidogenic fermentation enables an efficient production of VFAs from wastewater, whereas electrodialysis (ED) provides an effective approach to concentrate VFAs. However, these two processes have not been coupled in one single system previously. In this study, an acidogenesis-ED integrated system that coupled a continuous acidogenesis with a batch process of VFA concentration was developed for recovery of high-concentration VFAs from wastewater. Under 20.0 V voltage, the acetate was concentrated by 4-fold and the propionate and butyrate were concentrated by over 3-fold in the integrated system after 528-h operation. The declined VFAs recovery ratios at the later stage due to significant reverse diffusion indicate a need to prevent product over-accumulation. This work demonstrated the feasibility of the acidogenesis-ED integrated reactor for wastewater valorization and discussed the remaining challenges and opportunities.


Assuntos
Ácidos Graxos Voláteis , Águas Residuárias , Reatores Biológicos , Ácido Butírico , Fermentação , Concentração de Íons de Hidrogênio , Propionatos , Esgotos
4.
Bioresour Technol ; 250: 486-494, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29197771

RESUMO

The growing occurrence of antibiotics in water environment is causing increasing concern. To investigate the impact of frequently detected sulfadiazine on the formation of aerobic granular sludge, four sequencing batch reactors (SBRs) were set up with different environmentally relevant concentrations of sulfadiazine. Results showed that sulfadiazine pressure could lead to larger and more compact sludge particles and cause slight effect on reactor performance. Presence of sulfadiazine apparently increased the extracellular polymeric substances (EPS) secretion of microorganisms. Quantitative polymerase chain reaction (qPCR) showed that the abundances of sulfanilamide resistance genes in sludge increased with addition of sulfadiazine significantly. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) was used to predict functional genes, results showed that sulfadiazine led to an increase of specific functional genes. Thereby, it concluded that microorganisms could change the community structure by acclimating of functional bacteria and antibiotic resistance species to adapt to the antibiotic stress.


Assuntos
Reatores Biológicos , Esgotos , Aerobiose , Filogenia , Sulfadiazina , Eliminação de Resíduos Líquidos
5.
Mil Med Res ; 4: 26, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28828175

RESUMO

BACKGROUND: Craniocerebral gunshot injury refers to a wound caused by a bullet passing through or lodged in brain tissue, resulting in the loss of function of a certain area or other fatal damage to the human brain. Craniocerebral gunshot injury is usually life-threatening and is very common in modern warfare, accounting for the majority of battle casualties. Most of the patients suffer from acute cerebral infarction caused by vascular injury. Lack of early and solid battlefield emergency medical interference adds to the risk of death among the wounded. CASE PRESENTATION: We present a 24-year-old man who was shot with a shotgun from a distance of 15 m in an accidental injury. Forty-seven grapeshots were found on his body surface by physical examination. A computed tomography (CT) scan demonstrated large areas of low-density shadows in his right parietal lobe and right temporal lobe with the midline shifting to the left side 2 days later. Afterwards, the patient was transferred to our emergency medical center at Changzheng Hospital in Shanghai. Cranial computed tomography angiography (CTA) showed a high-density shadow in the initial part of the right middle cerebral artery. The branches after the initial part were obliterated. Prompt medical attention and decompressive craniotomy (DC) surgery contributed to the final recovery from cerebral infarction of this patient. CONCLUSION: Bullets can penetrate or be lodged in the brain, causing intracranial hypertension. The bullets lodged in the brain can result in stenosis and embolism of a cerebral artery, causing acute cerebral infarction. Combining dura turning-over surgery with DC surgery can not only decrease intracranial pressure, which can increase the blood supply for hypertension-induced vessel stenosis, but also help vessels outside the dura mater grow into ischemic areas of the cerebral cortex. However, this new pattern of surgery needs further support from evidence-based medicine.


Assuntos
Infarto Cerebral/cirurgia , Craniotomia/métodos , Descompressão Cirúrgica/métodos , Dura-Máter/cirurgia , Ferimentos por Arma de Fogo/complicações , Acidentes , Encéfalo/fisiopatologia , China , Craniotomia/normas , Descompressão Cirúrgica/normas , Dura-Máter/patologia , Dura-Máter/fisiopatologia , Humanos , Masculino , Tomografia Computadorizada por Raios X/métodos , Ferimentos por Arma de Fogo/cirurgia , Adulto Jovem
6.
Biotechnol Rep (Amst) ; 13: 13-18, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28352557

RESUMO

This study attempts to investigate the effect of phenol on physicochemical properties and treatment performances of partial nitrifying granules (PNGs). Two sequencing batch reactors (SBRs) fed with synthetic ammonium wastewaters were operated in absence (R1) or presence (R2) of phenol. The PNGs in R1 maintained excellent partial nitrification performance and relatively stable physicochemical properties, and exhibited compact and regular shaped structure with a cocci-dominant surface. However, as phenol concentration was stepwise increased from 0 to 300 mg/L in R2, filamentous bacteria appeared and gradually dominated within granules, which in turn resulted in settleability deterioration. Most notably, granules in R2 got easier to agglomerate in the reactor walls and then been washed out with effluent, leading to significant biomass loss, frequent outflow pipe blockage, and eventual system failure. The extracellular polymeric substances (EPS) contents including proteins and polysaccharides in R2 reached 1.8 and 1.7 times of that in R1, respectively, indicating that the presence of phenol played an important role on EPS production. Removal efficiency of ammonium and phenol remained high, but dropped sharply when phenol concentration reached 300 mg/L. Moreover, the failed maintenance of partial nitrification was observed due to the revival of nitrite oxidizing bacteria (NOB) within granules after phenol exposure, which was confirmed by quantitative fluorescence in situ hybridization (FISH) analysis. Overall this study demonstrates that phenol had negative effects on PNGs, and pretreatment to eliminate phenolic substances is recommended when using PNGs for wastewater treatment.

7.
Int J Surg Case Rep ; 24: 50-3, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27180320

RESUMO

INTRODUCTION: The cranioplasty is a classical surgical procedure to repair large skull defects. The prosthesis fracture was one rare complication following cranioplasty, which was only known to happen in traumatic head injury or child growing skull. PRESENTATION OF CASE: In the current report, we documented the first reported case of cranioplasty prosthesis fracture in an adult neurological trauma patient at the proximal pterion point region without head trauma. During the first cranioplasty, due to the cerebromalacia at temporal lobe, patient's temporalis muscle was not stripped from the dura mater and the prosthesis was anchored outside the temporalis muscle. Thus, no screw was used for anchoring the prosthesis at the basitemporal skull. The prosthesis fracture was observed on 12(th)-month post-surgically at the proximal pterion point region. During the second cranioplasty, the temporalis muscle was semi-partitioned from the back due to cerebromalacia recovery and five screws were used to anchor the prosthesis onto the basitemporal skull. The follow-up result was unremarkable on 21(st)-month post-second-cranioplasty. DISCUSSION: A dynamic load was generated on the prosthesis due to head-pillow contact during sleeping. Via the parietal tuber-temporozygomatic suture line, this inward load generates an outward force at the proximal pterion point region, where became a shearing force locating just right below the lowest screw anchoring in this region. This shearing force eventually led to prosthesis fracture at the proximal pterion point due to the fatigue effect. CONCLUSION: This case presented the importance of prosthesis anchoring location on the skull, especially when temporalis muscle was required to be preserved due to clinical necessity.

8.
Environ Sci Technol ; 50(7): 3882-9, 2016 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-26962848

RESUMO

Plant-microbial fuel cell (PMFC) is a renewable and sustainable energy technology that generates electricity with living plants. However, little information is available regarding the application of PMFC for the remediation of heavy metal contaminated water or soil. In this study, the potential for the removal of heavy metal Cr(VI) using PMFC was evaluated, and the performance of the PMFC at various initial Cr(VI) contents was investigated. The Cr(VI) removal efficiency could reached 99% under various conditions. Both the Cr(VI) removal rates and the removal efficiencies increased with the increasing initial Cr(VI) concentration. Furthermore, the long-term operation of the PMFC indicated that the system was stable and sustainable for Cr(VI) removal. The mass balance results and XPS analysis results demonstrate that only a small amount of soluble Cr(III) remained in the PMFC and that most Cr(III) precipitated in the form of the Cr(OH)3(s) or was adsorbed onto the electrodes. The PMFC experiments of without acetate addition also show that plants can provide carbon source for MFC through secrete root exudates and bioelectrochemical reduction of Cr(VI) was the main mechanism for the Cr(VI) removal. These results extend the application fields of PMFC and might provide a new insight for Cr(VI) removal from wastewater or soil.


Assuntos
Fontes de Energia Bioelétrica , Cromo/isolamento & purificação , Lolium/metabolismo , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Cromo/metabolismo , Eletrodos , Desenho de Equipamento , Cinética , Plantas , Poluentes Químicos da Água/metabolismo
9.
Sci Rep ; 5: 16281, 2015 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-26541793

RESUMO

Recovering nutrients, especially phosphate resource, from wastewater have attracted increasing interest recently. Herein, an intermittently aerated membrane bioreactor (MBR) with a mesh filter was developed for simultaneous chemical oxygen demand (COD), total nitrogen (TN) and phosphorous removal, followed by phosphorus recovery from the phosphorus-rich sludge. This integrated system showed enhanced performances in nitrification and denitrification and phosphorous removal without excess sludge discharged. The removal of COD, TN and total phosphorus (TP) in a modified MBR were averaged at 94.4 ± 2.5%, 94.2 ± 5.7% and 53.3 ± 29.7%, respectively. The removed TP was stored in biomass, and 68.7% of the stored phosphorous in the sludge could be recovered as concentrated phosphate solution with a concentration of phosphate above 350 mg/L. The sludge after phosphorus release could be returned back to the MBR for phosphorus uptake, and 83.8% of its capacity could be recovered.


Assuntos
Reatores Biológicos , Carbono/isolamento & purificação , Membranas Artificiais , Nitrogênio/isolamento & purificação , Fósforo/isolamento & purificação , Ar , Biofilmes , Esgotos
10.
Ecotoxicology ; 24(10): 2175-80, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26410373

RESUMO

Microbial fuel cells (MFCs) have emerged as a promising technology for wastewater treatment with concomitant energy production but the performance is usually limited by low microbial activities. This has spurred intensive research interest for microbial enhancement. This study demonstrated an interesting stimulation effect of a static magnetic field (MF) on sludge-inoculated MFCs and explored into the mechanisms. The implementation of a 100-mT MF accelerated the reactor startup and led to increased electricity generation. Under the MF exposure, the activation loss of the MFC was decreased, but there was no increased secretion of redox mediators. Thus, the MF effect was mainly due to enhanced bioelectrochemical activities of anodic microorganisms, which are likely attributed to the oxidative stress and magnetohydrodynamic effects under an MF exposure. This work implies that weak MF may be applied as a simple and effective approach to stimulate microbial activities for various bioelectrochemical energy production and decontamination applications.


Assuntos
Fontes de Energia Bioelétrica , Biocombustíveis/análise , Campos Magnéticos , Eletricidade
11.
Sci Rep ; 5: 10387, 2015 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-25997399

RESUMO

An electrochemical membrane bioreactor (EMBR) has recently been developed for energy recovery and wastewater treatment. The hydrodynamics of the EMBR would significantly affect the mass transfers and reaction kinetics, exerting a pronounced effect on reactor performance. However, only scarce information is available to date. In this study, the hydrodynamic characteristics of the EMBR were investigated through various approaches. Tracer tests were adopted to generate residence time distribution curves at various hydraulic residence times, and three hydraulic models were developed to simulate the results of tracer studies. In addition, the detailed flow patterns of the EMBR were acquired from a computational fluid dynamics (CFD) simulation. Compared to the tank-in-series and axial dispersion ones, the Martin model could describe hydraulic performance of the EBMR better. CFD simulation results clearly indicated the existence of a preferential or circuitous flow in the EMBR. Moreover, the possible locations of dead zones in the EMBR were visualized through the CFD simulation. Based on these results, the relationship between the reactor performance and the hydrodynamics of EMBR was further elucidated relative to the current generation. The results of this study would benefit the design, operation and optimization of the EMBR for simultaneous energy recovery and wastewater treatment.


Assuntos
Hidrodinâmica , Modelos Teóricos , Reatores Biológicos , Eliminação de Resíduos Líquidos/instrumentação , Eliminação de Resíduos Líquidos/métodos
12.
Chemosphere ; 140: 79-84, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24880609

RESUMO

A novel energy-saving anaerobic hybrid membrane bioreactor (AnHMBR) with mesh filter, which takes advantage of anaerobic membrane bioreactor and fixed-bed biofilm reactor, is developed for low-strength 2-chlorophenol (2-CP)-contained wastewater treatment. In this system, the anaerobic membrane bioreactor is stuffed with granular activated carbon to construct an anaerobic hybrid fixed-bed biofilm membrane bioreactor. The effluent turbidity from the AnHMBR system was low during most of the operation period, and the chemical oxygen demand and 2-CP removal efficiencies averaged 82.3% and 92.6%, respectively. Furthermore, a low membrane fouling rate was achieved during the operation. During the AnHMBR operation, the only energy consumption was for feed pump. And a low energy demand of 0.0045-0.0063kWhm(-3) was estimated under the current operation conditions. All these results demonstrated that this novel AnHMBR is a sustainable technology for treating 2-CP-contained wastewater.


Assuntos
Reatores Biológicos , Clorofenóis/metabolismo , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química , Poluentes Químicos da Água/metabolismo , Anaerobiose , Biofilmes , Análise da Demanda Biológica de Oxigênio , Carvão Vegetal , Clorofenóis/análise , Conservação de Recursos Energéticos/métodos , Membranas Artificiais , Águas Residuárias/microbiologia , Poluentes Químicos da Água/análise
13.
Sci Rep ; 4: 6779, 2014 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-25345502

RESUMO

In this study, based on a simple, compact and submersible microbial fuel cell (MFC), a novel online monitoring and alert system with self-diagnosis function was established for the activated sludge (AS) process. Such a submersible MFC utilized organic substrates and oxygen in the AS reactor as the electron donor and acceptor respectively, and could provide an evaluation on the status of the AS reactor and thus give a reliable early warning of potential risks. In order to evaluate the reliability and sensitivity of this online monitoring and alert system, a series of tests were conducted to examine the response of this system to various shocks imposed on the AS reactor. The results indicate that this online monitoring and alert system was highly sensitive to the performance variations of the AS reactor. The stability, sensitivity and repeatability of this online system provide feasibility of being incorporated into current control systems of wastewater treatment plants to real-time monitor, diagnose, alert and control the AS process.


Assuntos
Fontes de Energia Bioelétrica , Sistemas On-Line , Esgotos , Gerenciamento de Resíduos/métodos
14.
Bioresour Technol ; 171: 472-6, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25182424

RESUMO

Quorum sensing (QS) and quorum quenching (QQ) are two antagonistic processes coexisting in various bacterial communities in bioreactors, e.g., activated sludge for biological wastewater treatment. Although QS signal molecules are detected in activated sludge reactors and known to affect sludge properties and reactor performance, there has been no direct evidence to prove the endogenous existence of QQ effects in activated sludge. In this study, for the first time, acyl homoserine lactones-degrading enzymatic activity, a typical QQ effect, was discovered in activated sludge and found to considerably affect the QS detection results. The coexistence of QS and QQ bacteria in activated sludge was further confirmed by bacterial screening and denaturing gradient gel electrophoresis analysis. The method developed in this study could also be used to evaluate QQ activities in bioreactors, and a possible way is provided to tune bioreactor performance through balancing the QS and QQ processes.


Assuntos
Reatores Biológicos , Percepção de Quorum/fisiologia , Esgotos/microbiologia , Eliminação de Resíduos Líquidos/métodos , Purificação da Água/métodos , Acil-Butirolactonas/metabolismo , Eletroforese em Gel de Gradiente Desnaturante , Microscopia Confocal , Estrutura Molecular
15.
Water Res ; 47(15): 5794-800, 2013 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-23886542

RESUMO

How to mitigate membrane fouling remains a critical challenge for widespread application of membrane bioreactors. Herein, an antifouling electrochemical membrane bioreactor (EMBR) was developed based on in-situ utilization of the generated electricity for fouling control. In this system, a maximum power density of 1.43 W/m(3) and a current density of 18.49 A/m(3) were obtained. The results demonstrate that the formed electric field reduced the deposition of sludge on membrane surface by enhancing the electrostatic repulsive force between them. The produced H2O2 at the cathode also contributed to the fouling mitigation by in-situ removing the membrane foulants. In addition, 93.7% chemical oxygen demand (COD) removal and 96.5% NH4(+)-N removal in average as well as a low effluent turbidity of below 2 NTU were achieved, indicating a good wastewater treatment performance of the EMBR. This work provides a proof-of-concept study of an antifouling MBR with high wastewater treatment efficiency and electricity recovery, and implies that electrochemical control might provide another promising avenue to in-situ suppress the membrane fouling in MBRs.


Assuntos
Reatores Biológicos/microbiologia , Membranas Artificiais , Esgotos/microbiologia , Análise da Demanda Biológica de Oxigênio , Eletricidade , Purificação da Água/métodos
16.
Sci Rep ; 3: 1864, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23689529

RESUMO

One possible way to address both water and energy shortage issues, the two of major global challenges, is to recover energy and water resource from wastewater. Herein, a novel electrochemical membrane bioreactor (EMBR) was developed to recover energy from wastewater and meantime harvest clean water for reuse. With the help of the microorganisms in the biocatalysis and biodegradation process, net electricity could be recovered from a low-strength synthetic wastewater after estimating total energy consumption of this system. In addition, high-quality clean water was obtained for reuse. The results clearly demonstrate that, under the optimized operating conditions, it is possible to recover net energy from wastewater, while at the same time to harvest high-quality effluent for reuse with this novel wastewater treatment system.


Assuntos
Biodegradação Ambiental , Eletricidade , Técnicas Eletroquímicas/métodos , Membranas Artificiais , Eliminação de Resíduos Líquidos , Águas Residuárias/microbiologia , Purificação da Água/métodos , Reatores Biológicos , Águas Residuárias/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação
17.
Bioresour Technol ; 122: 17-21, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22595097

RESUMO

A pilot-scale submerged membrane bioreactor (MBR) using nylon mesh as filter was investigated for treatment of low-strength municipal wastewater (average influent COD=145.7±59.9 mg/L). During the operation, biomass was effectively retained by the nylon mesh with biofilm attached, and a low effluent turbidity of below 2 NTU was obtained. The average COD and NH(4)(+)-N removal efficiencies reached 86.3% and 98.1%, respectively, at a hydraulic retention time of 5 h. A sludge concentration of 4.15±0.15 g/L was maintained in the system without excess sludge discharge, attributed to the prolonged solid retention time and low organic loading rate. The low sludge concentration was also beneficial for mitigating the filter fouling. Thus, this mesh filter MBR provides a low-cost, efficient and simple approach to treat municipal wastewater, and shows a high potential for application in rural and sparsely populated areas.


Assuntos
Reatores Biológicos , Cidades , Filtração/instrumentação , Membranas Artificiais , Águas Residuárias/análise , Purificação da Água/instrumentação , Amônia/análise , Biodegradação Ambiental , Biodiversidade , Análise da Demanda Biológica de Oxigênio , Reatores Biológicos/microbiologia , China , Nitrogênio/análise , Fósforo/análise , Projetos Piloto , Pressão , Esgotos/microbiologia , Eliminação de Resíduos Líquidos , Águas Residuárias/microbiologia
18.
Bioresour Technol ; 122: 22-6, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22370232

RESUMO

Conventional MBR has been mostly based on floc sludge and the use of costly microfiltration membranes. Here, a novel aerobic granule (AG)-mesh filter MBR (MMBR) process was developed for cost-effective wastewater treatment. During 32-day continuous operation, a predominance of granules was maintained in the system, and good filtration performance was achieved at a low trans-membrane pressure (TMP) of below 0.025 m. The granules showed a lower fouling propensity than sludge flocs, attributed to the formation of more porous biocake layer at mesh surface. A low-flux and low-TMP filtration favored a stable system operation. In addition, the reactor had high pollutant removal efficiencies, with a 91.4% chemical oxygen demand removal, 95.7% NH(4)(+) removal, and a low effluent turbidity of 4.1 NTU at the stable stage. This AG-MMBR process offers a promising technology for low-cost and efficient treatment of wastewaters.


Assuntos
Reatores Biológicos/economia , Filtração/instrumentação , Membranas Artificiais , Esgotos/microbiologia , Águas Residuárias/análise , Purificação da Água/economia , Purificação da Água/instrumentação , Aerobiose , Biodegradação Ambiental , Reatores Biológicos/microbiologia , Análise Custo-Benefício , Filtração/economia , Pressão , Águas Residuárias/economia , Águas Residuárias/microbiologia
19.
Environ Sci Technol ; 45(21): 9256-61, 2011 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-21978391

RESUMO

A novel bioelectrochemical membrane reactor (BEMR), which takes advantage of a membrane bioreactor (MBR) and microbial fuel cells (MFC), is developed for wastewater treatment and energy recovery. In this system, stainless steel mesh with biofilm formed on it serves as both the cathode and the filtration material. Oxygen reduction reactions are effectively catalyzed by the microorganisms attached on the mesh. The effluent turbidity from the BEMR system was low during most of the operation period, and the chemical oxygen demand and NH(4)(+)-N removal efficiencies averaged 92.4% and 95.6%, respectively. With an increase in hydraulic retention time and a decrease in loading rate, the system performance was enhanced. In this BEMR process, a maximum power density of 4.35 W/m(3) and a current density of 18.32 A/m(3) were obtained at a hydraulic retention time of 150 min and external resister of 100 Ω. The Coulombic efficiency was 8.2%. Though the power density and current density of the BEMR system were not very high, compared with other high-output MFC systems, electricity recovery could be further enhanced through optimizing the operation conditions and BEMR configurations. Results clearly indicate that this innovative system holds great promise for efficient treatment of wastewater and energy recovery.


Assuntos
Reatores Biológicos , Eletroquímica , Membranas Artificiais , Eliminação de Resíduos Líquidos/métodos , Fontes de Energia Bioelétrica
20.
Biosens Bioelectron ; 26(10): 3987-92, 2011 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-21493055

RESUMO

The electricity production of Shewanella-inoculated microbial fuel cells (MFCs) under magnetic field (MF) exposure was investigated in different reactor systems. The persistency of the MF effect and the influences of MF intensity and direction on MFC performance were also studied. Application of a 100-mT static MF to the MFCs improved electricity production considerably, with an increase in the maximum voltage by 20-27% in both single- and two-chamber MFCs, while a more conspicuous improvement in the electricity generation was observed in a three-electrode cell. The MF effects were found to be immediate and reversible, and adverse effects seemed to occur when the MF was suddenly removed. The medium components analysis demonstrated that the application of MF led to an enhanced bioelectrochemical activity of Shewanella, and no significant promotion in mediator secretion was found. The improvement in the electricity production of MFCs under MF was mainly attributed to the enhanced bioelectrochemical activity, possibly through the oxidative stress mechanism. An accelerated cell growth under MF might also contribute to the enhanced substrate degradation and power generation.


Assuntos
Fontes de Energia Bioelétrica/microbiologia , Shewanella/metabolismo , Reatores Biológicos/microbiologia , Eletricidade , Técnicas Eletroquímicas , Magnetismo , Estresse Oxidativo , Shewanella/crescimento & desenvolvimento
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