RESUMO
Introducción La ludificación consiste en emplear el juego en contextos no lúdicos. Su uso en la rehabilitación motora de patologías neurológicas está muy extendido, pero sobre todo en pacientes adultos. El objetivo de esta revisión fue describir el uso de la ludificación en los tratamientos de rehabilitación en niños y adolescentes con afectación neuromotora. Métodos Se realizó una revisión sistemática de ensayos clínicos en diferentes bases de datos: Medline (a través de Pubmed), Scielo, SCOPUS, Dialnet, Cinahl y PEDro de la literatura científica publicada hasta la fecha siguiendo el protocolo PRISMA. La calidad metodológica de los estudios identificados se evaluó a través de la escala PEDro. Resultados De un total de 469 estudios localizados se seleccionaron 10 ensayos clínicos que cumplieron los criterios de inclusión. Se analizaron los sistemas de ludificación utilizados como parte del tratamiento rehabilitador en distintas afecciones neuromotoras en niños y adolescentes. La parálisis cerebral fue la afección con mayor número de estudios (n = 6), seguida del trastorno del desarrollo de la coordinación (n = 3). También se estudió la alteración del equilibrio y coordinación por causa neurológica (n = 1). Conclusión El uso de la ludificación en rehabilitación aporta beneficios al tratamiento convencional de las alteraciones neuromotoras en niños y adolescentes, siendo el incremento de la motivación y de la adherencia terapéutica los que mayor consenso han alcanzado entre autores. Fuerza, equilibrio, funcionalidad y coordinación son otras variables analizadas que, si bien sugieren mejoras, necesitarían futuras investigaciones para determinar una óptima dosificación. (AU)
Introduction Gamification consists of the use of games in non-playful contexts. It is widely employed in the motor rehabilitation of neurological diseases, but mainly in adult patients. The objective of this review was to describe the use of gamification in the rehabilitation of children and adolescents with neuromotor impairment. Methods We performed a systematic review of clinical trials published to date on the MEDLINE (PubMed), Scielo, SCOPUS, Dialnet, CINAHL, and PEDro databases, following the PRISMA protocol. The methodological quality of the studies identified was assessed using the PEDro scale. Results From a total of 469 studies, 10 clinical trials met the inclusion criteria. We analysed the gamification systems used as part of the rehabilitation treatment of different neuromotor conditions in children and adolescents. Cerebral palsy was the most frequently studied condition (6 studies), followed by developmental coordination disorder (3), and neurological impairment of balance and coordination (1). Conclusion The use of gamification in rehabilitation is helpful in the conventional treatment of neuromotor disorders in children and adolescents, with increased motivation and therapeutic adherence being the benefits with the greatest consensus among authors. While strength, balance, functional status, and coordination also appear to improve, future research should aim to determine an optimal dosage. (AU)
Assuntos
Humanos , Recém-Nascido , Lactente , Pré-Escolar , Criança , Adolescente , Reabilitação NeurológicaRESUMO
Introducción La ludificación consiste en emplear el juego en contextos no lúdicos. Su uso en la rehabilitación motora de patologías neurológicas está muy extendido, pero sobre todo en pacientes adultos. El objetivo de esta revisión fue describir el uso de la ludificación en los tratamientos de rehabilitación en niños y adolescentes con afectación neuromotora. Métodos Se realizó una revisión sistemática de ensayos clínicos en diferentes bases de datos: Medline (a través de Pubmed), Scielo, SCOPUS, Dialnet, Cinahl y PEDro de la literatura científica publicada hasta la fecha siguiendo el protocolo PRISMA. La calidad metodológica de los estudios identificados se evaluó a través de la escala PEDro. Resultados De un total de 469 estudios localizados se seleccionaron 10 ensayos clínicos que cumplieron los criterios de inclusión. Se analizaron los sistemas de ludificación utilizados como parte del tratamiento rehabilitador en distintas afecciones neuromotoras en niños y adolescentes. La parálisis cerebral fue la afección con mayor número de estudios (n = 6), seguida del trastorno del desarrollo de la coordinación (n = 3). También se estudió la alteración del equilibrio y coordinación por causa neurológica (n = 1). Conclusión El uso de la ludificación en rehabilitación aporta beneficios al tratamiento convencional de las alteraciones neuromotoras en niños y adolescentes, siendo el incremento de la motivación y de la adherencia terapéutica los que mayor consenso han alcanzado entre autores. Fuerza, equilibrio, funcionalidad y coordinación son otras variables analizadas que, si bien sugieren mejoras, necesitarían futuras investigaciones para determinar una óptima dosificación. (AU)
Introduction Gamification consists of the use of games in non-playful contexts. It is widely employed in the motor rehabilitation of neurological diseases, but mainly in adult patients. The objective of this review was to describe the use of gamification in the rehabilitation of children and adolescents with neuromotor impairment. Methods We performed a systematic review of clinical trials published to date on the MEDLINE (PubMed), Scielo, SCOPUS, Dialnet, CINAHL, and PEDro databases, following the PRISMA protocol. The methodological quality of the studies identified was assessed using the PEDro scale. Results From a total of 469 studies, 10 clinical trials met the inclusion criteria. We analysed the gamification systems used as part of the rehabilitation treatment of different neuromotor conditions in children and adolescents. Cerebral palsy was the most frequently studied condition (6 studies), followed by developmental coordination disorder (3), and neurological impairment of balance and coordination (1). Conclusion The use of gamification in rehabilitation is helpful in the conventional treatment of neuromotor disorders in children and adolescents, with increased motivation and therapeutic adherence being the benefits with the greatest consensus among authors. While strength, balance, functional status, and coordination also appear to improve, future research should aim to determine an optimal dosage. (AU)
Assuntos
Humanos , Recém-Nascido , Lactente , Pré-Escolar , Criança , Adolescente , Reabilitação NeurológicaRESUMO
Among leaf-nosed bats (family Phyllostomidae), the genus Leptonycteris (subfamily Glossophaginae), contains three migratory and obligate nectar-dwelling species of great ecological and economic importance; the greater long-nosed bat L. nivalis, the lesser long-nosed bat L. yerbabuenae, and the southern long-nosed bat L. curasoae. According to the IUCN, the three species are categorized as 'vulnerable', 'endangered', and 'near threatened', respectively. In this study, we assembled and characterized in detail the mitochondrial genome of Leptonycteris spp. and examined the phylogenetic position of this genus in the family Phyllostomidae based on protein coding genes (PCGs). The mitogenomes of L. nivalis, L. curasoae, and L. yerbabuenae are 16,708, 16,758, and 16,729 bp in length and each encode 13 PCGs, 22 transfer RNA genes, 2 rRNA genes, and a putative control region (CR). Mitochondrial gene order is identical to that reported before for the family Phyllostomidae. All tRNAs exhibit a 'cloverleaf' secondary structure, except tRNA-Serine-1 that is missing the DHU arm in the three species. All PCGs are exposed to purifying selection with atp8 experiencing the most relaxed purifying selection as the ω ratio was higher for this gene compared to the other PCGs in each species. The CR of each species contains three functional domains: extended termination associated sequence (ETAS), Central, and conserved sequence block domain (CSB). A phylomitogenomic analysis revealed that Leptonycteris is monophyletic and most closely related to the genus Glossophaga. The analysis also supported the monophyly of the family Glossophaginae in the speciose family Phyllostomidae. The mitochondria characterization of these species provides relevant information to develop molecular markers for conservation purposes.
Assuntos
Quirópteros , Genoma Mitocondrial , Animais , Filogenia , Quirópteros/genética , Néctar de Plantas , Genômica , Mitocôndrias/genética , Genoma Mitocondrial/genética , RNA de Transferência/genéticaRESUMO
This work investigates H2 production through aqueous phase reforming (APR) of synthetic brewery wastewater in a continuous fixed bed reactor with Pt and PtRe (3 wt %) catalysts supported on activated carbon. The influence of weight hourly space velocity (WHSV) and superficial Ar gas flow velocity (VAr) was assessed for the sake of optimisation, while reaction temperature and pressure were maintained at 225 °C and 28 bar, respectively. H2 production was found to be higher using the PtRe catalyst at the lowest WHSV (0.03 h-1) and highest VAr (0.8 cm s-1). The comparison of the maximum H2 production obtained in this work (27.9 µmol min-1) with other treatment processes shows the potential of the application of APR process for H2 production from brewery wastewater. Despite the different reaction conditions tested, the catalysts showed deactivation with time on stream, which was related to the formation of solid deposits on the surface of the catalysts. Therefore, future research should be related to the development of more stable catalysts, strategies that avoid deactivation by coking and regeneration processes.
Assuntos
Águas Residuárias , Água , Catálise , TemperaturaRESUMO
INTRODUCTION: Gamification consists of the use of games in non-playful contexts. It is widely employed in the motor rehabilitation of neurological diseases, but mainly in adult patients. The objective of this review was to describe the use of gamification in the rehabilitation of children and adolescents with neuromotor impairment. METHODS: We performed a systematic review of clinical trials published to date on the MEDLINE (PubMed), Scielo, SCOPUS, Dialnet, CINAHL, and PEDro databases, following the PRISMA protocol. The methodological quality of the studies identified was assessed using the PEDro scale. RESULTS: From a total of 469 studies, 10 clinical trials met the inclusion criteria. We analysed the gamification systems used as part of the rehabilitation treatment of different neuromotor conditions in children and adolescents. Cerebral palsy was the most frequently studied condition (6studies), followed by developmental coordination disorder (3), and neurological impairment of balance and coordination (1). CONCLUSION: The use of gamification in rehabilitation is helpful in the conventional treatment of neuromotor disorders in children and adolescents, with increased motivation and therapeutic adherence being the benefits with the greatest consensus among authors. While strength, balance, functional status, and coordination also appear to improve, future research should aim to determine an optimal dosage.
RESUMO
Aqueous phase reforming (APR) coupled to catalytic wet air oxidation (CWAO) has been investigated as an approach to remove phenolic compounds from wastewater, converting them into valuable gases. Partial oxidation of phenol was achieved in the first CWAO stage trying to minimize mineralization so to allow a high yield to valuable gases in the second APR stage. APR runs were carried out with different mixtures of compounds corresponding to phenol oxidation pathway (phenol, quinones, long and short chain acids) and representing different degrees of oxidation in CWAO stage. A range of TOC and COD removal (74-90%) was observed in APR stage for the single compounds, with higher removal for long chain acids. Likewise, long chain acids provided with the highest conversion to gases. APR of mixtures rich in acids gave the highest yield to CH4 (11.0 mmol CH4/g TOCinitial). H2 production was low in all cases, due to competing direct conversion of long and short chain acids into CH4. TOC and COD removal from wastewater was similar in APR-CWAO and APR, however the conversion to gases and the yield to CH4 were markedly higher for APR-CWAO, thus overcoming the difficulties previously observed in the direct APR of phenol.
Assuntos
Águas Residuárias , Poluentes Químicos da Água , Catálise , Oxirredução , Fenóis , Eliminação de Resíduos LíquidosRESUMO
Ultrasound guidance is not in widespread use in prostate cancer radiotherapy workflows. This can be partially attributed to the need for image interpretation by a trained operator during ultrasound image acquisition. In this work, a one-class regressor, based on DenseNet and Gaussian processes, was implemented to automatically assess the quality of transperineal ultrasound images of the male pelvic region. The implemented deep learning approach was tested on 300 transperineal ultrasound images and it achieved a scoring accuracy of 94%, a specificity of 95% and a sensitivity of 92% with respect to the majority vote of 3 experts, which was comparable with the results of these experts. This is the first step toward a fully automatic workflow, which could potentially remove the need for ultrasound image interpretation and make real-time volumetric organ tracking in the radiotherapy environment using ultrasound more appealing.
Assuntos
Aprendizado Profundo , Pelve/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Humanos , Masculino , Pessoa de Meia-Idade , Períneo , Ultrassonografia/métodos , Ultrassonografia/normasRESUMO
PURPOSE: To develop a new optimization algorithm to carry out true dose painting by numbers (DPBN) planning based on full Monte Carlo (MC) calculation. METHODS: Four configurations with different clustering of the voxel values from PET data were proposed. An optimization method at the voxel level under Lineal Programming (LP) formulation was used for an inverse planning and implemented in CARMEN, an in-house Monte Carlo treatment planning system. RESULTS: Beamlet solutions fulfilled the objectives and did not show significant differences between the different configurations. More differences were observed between the segment solutions. The plan for the dose prescription map without clustering was the better solution. CONCLUSIONS: LP optimization at voxel level without dose-volume restrictions can carry out true DPBN planning with the MC accuracy.
Assuntos
Método de Monte Carlo , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Carcinoma Pulmonar de Células não Pequenas/diagnóstico por imagem , Carcinoma Pulmonar de Células não Pequenas/radioterapia , Fluordesoxiglucose F18 , Humanos , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/radioterapia , Fótons , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Compostos RadiofarmacêuticosRESUMO
[This corrects the article DOI: 10.1371/journal.pone.0166767.].
RESUMO
A model based on a specific phantom, called QuAArC, has been designed for the evaluation of planning and verification systems of complex radiotherapy treatments, such as volumetric modulated arc therapy (VMAT). This model uses the high accuracy provided by the Monte Carlo (MC) simulation of log files and allows the experimental feedback from the high spatial resolution of films hosted in QuAArC. This cylindrical phantom was specifically designed to host films rolled at different radial distances able to take into account the entrance fluence and the 3D dose distribution. Ionization chamber measurements are also included in the feedback process for absolute dose considerations. In this way, automated MC simulation of treatment log files is implemented to calculate the actual delivery geometries, while the monitor units are experimentally adjusted to reconstruct the dose-volume histogram (DVH) on the patient CT. Prostate and head and neck clinical cases, previously planned with Monaco and Pinnacle treatment planning systems and verified with two different commercial systems (Delta4 and COMPASS), were selected in order to test operational feasibility of the proposed model. The proper operation of the feedback procedure was proved through the achieved high agreement between reconstructed dose distributions and the film measurements (global gamma passing rates > 90% for the 2%/2 mm criteria). The necessary discretization level of the log file for dose calculation and the potential mismatching between calculated control points and detection grid in the verification process were discussed. Besides the effect of dose calculation accuracy of the analytic algorithm implemented in treatment planning systems for a dynamic technique, it was discussed the importance of the detection density level and its location in VMAT specific phantom to obtain a more reliable DVH in the patient CT. The proposed model also showed enough robustness and efficiency to be considered as a pre-treatment VMAT verification system.
Assuntos
Dosimetria Fotográfica/métodos , Neoplasias de Cabeça e Pescoço/radioterapia , Neoplasias da Próstata/radioterapia , Radioterapia de Intensidade Modulada/instrumentação , Simulação por Computador , Retroalimentação , Humanos , Masculino , Modelos Teóricos , Método de Monte Carlo , Imagens de FantasmasRESUMO
The anoxic-oxic (A/O) municipal wastewater treatment plant (WWTP) of Manresa (Catalonia, Spain) was studied for a possible conversion to an anaerobic/anoxic/oxic (A2/O) configuration to promote enhanced biological phosphorus removal. The control structure had to be redesigned to satisfy the new necessity to control phosphorus concentration, besides ammonium and nitrate concentrations (main pollutant concentrations). Thereby, decentralized control structures with proportional-integral-derivative (PID) controllers and centralized control structures with model-predictive controllers (MPC) were designed and tested. All the designed control structures had their performance systematically tested regarding effluent quality and operating costs. The centralized control structure, A2/O-3-MPC, achieved the lowest operating costs with the best effluent quality using the A2/O plant configuration for the Manresa WWTP. The controlled variables used in this control structure were ammonium in the effluent, nitrate at the end of the anoxic zone and phosphate at the end of the anaerobic zone, while the manipulated variables were the internal and external recycle flow rates and the dissolved oxygen setpoint in the aerobic reactors.
Assuntos
Fósforo/metabolismo , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/metabolismo , Modelos Teóricos , Oxigênio/análise , Espanha , Eliminação de Resíduos Líquidos/instrumentaçãoRESUMO
PURPOSE: The authors present a hybrid direct multileaf collimator (MLC) aperture optimization model exclusively based on sequencing of patient imaging data to be implemented on a Monte Carlo treatment planning system (MC-TPS) to allow the explicit radiation transport simulation of advanced radiotherapy treatments with optimal results in efficient times for clinical practice. METHODS: The planning system (called CARMEN) is a full MC-TPS, controlled through aMATLAB interface, which is based on the sequencing of a novel map, called "biophysical" map, which is generated from enhanced image data of patients to achieve a set of segments actually deliverable. In order to reduce the required computation time, the conventional fluence map has been replaced by the biophysical map which is sequenced to provide direct apertures that will later be weighted by means of an optimization algorithm based on linear programming. A ray-casting algorithm throughout the patient CT assembles information about the found structures, the mass thickness crossed, as well as PET values. Data are recorded to generate a biophysical map for each gantry angle. These maps are the input files for a home-made sequencer developed to take into account the interactions of photons and electrons with the MLC. For each linac (Axesse of Elekta and Primus of Siemens) and energy beam studied (6, 9, 12, 15 MeV and 6 MV), phase space files were simulated with the EGSnrc/BEAMnrc code. The dose calculation in patient was carried out with the BEAMDOSE code. This code is a modified version of EGSnrc/DOSXYZnrc able to calculate the beamlet dose in order to combine them with different weights during the optimization process. RESULTS: Three complex radiotherapy treatments were selected to check the reliability of CARMEN in situations where the MC calculation can offer an added value: A head-and-neck case (Case I) with three targets delineated on PET/CT images and a demanding dose-escalation; a partial breast irradiation case (Case II) solved with photon and electron modulated beams (IMRT + MERT); and a prostatic bed case (Case III) with a pronounced concave-shaped PTV by using volumetric modulated arc therapy. In the three cases, the required target prescription doses and constraints on organs at risk were fulfilled in a short enough time to allow routine clinical implementation. The quality assurance protocol followed to check CARMEN system showed a high agreement with the experimental measurements. CONCLUSIONS: A Monte Carlo treatment planning model exclusively based on maps performed from patient imaging data has been presented. The sequencing of these maps allows obtaining deliverable apertures which are weighted for modulation under a linear programming formulation. The model is able to solve complex radiotherapy treatments with high accuracy in an efficient computation time.
Assuntos
Método de Monte Carlo , Tomografia por Emissão de Pósitrons/métodos , Programação Linear , Planejamento da Radioterapia Assistida por Computador/métodos , Tomografia Computadorizada por Raios X/métodos , Algoritmos , Neoplasias da Mama/radioterapia , Simulação por Computador , Elétrons/uso terapêutico , Estudos de Viabilidade , Neoplasias de Cabeça e Pescoço/radioterapia , Humanos , Masculino , Modelos Biológicos , Imagens de Fantasmas , Fótons/uso terapêutico , Tomografia por Emissão de Pósitrons/instrumentação , Neoplasias da Próstata/radioterapia , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/instrumentação , Radioterapia de Intensidade Modulada/instrumentação , Radioterapia de Intensidade Modulada/métodos , Fatores de Tempo , Tomografia Computadorizada por Raios X/instrumentaçãoRESUMO
Nitrogen removal via the nitrite pathway results in significant savings in both aeration costs and COD requirements for denitrification when compared to the conventional biological nitrogen removal process. Implementation of the nitrite pathway for simultaneous C/N/P removal in a single sludge system has a major drawback: the aeration phase disfavours denitrifying phosphorus removal. A possible configuration to overcome this issue is the utilisation of a two-sludge system where autotrophic and heterotrophic populations are physically separated. This paper experimentally demonstrates the feasibility of a nitrite-based two-sludge system with sequencing batch reactors (SBR) for the treatment of urban wastewater: a heterotrophic SBR with denitrifying PAOs for P removal and an aerobic SBR for N removal. Partial nitrification was attained in the autotrophic SBR so that shortcut biological nitrogen removal was achieved by using the anoxic dephosphatation activity of DPAOs. Finally, the effect of operating this system without pH control was studied using different influent pH values (pH = 6.8, 7.5 and 8.2) and, despite some efficiency lost due to the pH fluctuations, the system was able to remove most of the C, N and P present in the wastewater.
Assuntos
Carbono/isolamento & purificação , Nitritos/metabolismo , Nitrogênio/isolamento & purificação , Fósforo/isolamento & purificação , Esgotos/microbiologia , Carbono/metabolismo , Nitrogênio/metabolismo , Fósforo/metabolismo , Eliminação de Resíduos LíquidosRESUMO
The sexual system of the symbiotic shrimp Thor amboinensis is described, along with observations on sex ratio and host-use pattern of different populations. We used a comprehensive approach to elucidate the previously unknown sexual system of this shrimp. Dissections, scanning electron microscopy, size-frequency distribution analysis, and laboratory observations demonstrated that T. amboinensis is a protandric hermaphrodite: shrimp first mature as males and change into females later in life. Thor amboinensis inhabited the large and structurally heterogeneous sea anemone Stichodactyla helianthus in large groups (up to 11 individuals) more frequently than expected by chance alone. Groups exhibited no particularly complex social structure and showed male-biased sex ratios more frequently than expected by chance alone. The adult sex ratio was male-biased in the four separate populations studied, one of them being thousands of kilometers apart from the others. This study supports predictions central to theories of resource monopolization and sex allocation. Dissections demonstrated that unusually large males were parasitized by an undescribed species of isopod (family Entoniscidae). Infestation rates were similarly low in both sexes (≈11%-12%). The available information suggests that T. amboinensis uses pure search promiscuity as a mating system. This hypothesis needs to be formally tested with mating behavior observations and field measurements on the movement pattern of both sexes of the species. Further detailed studies on the lifestyle and sexual system of all the species within this genus and the development of a molecular phylogeny are necessary to elucidate the evolutionary history of gender expression in the genus Thor.
Assuntos
Crustáceos/anatomia & histologia , Crustáceos/fisiologia , Organismos Hermafroditas/fisiologia , Animais , Tamanho Corporal , Dissecação , Genitália/anatomia & histologia , Microscopia Eletrônica de Varredura , Anêmonas-do-Mar/parasitologia , Razão de MasculinidadeRESUMO
Nitrogen removal via nitrite has recently gained a lot of interest because it results in significant savings in both aeration costs and COD (chemical oxygen demand) requirements for denitrification, when compared to the conventional biological nitrogen removal via nitrate. The effectiveness of two different control strategies to achieve the nitrite pathway in systems with sludge retention has been experimentally demonstrated: (i) control of aerobic phase length, with which aeration is terminated as soon as ammonia is completely oxidised; (ii) operation at low DO setpoints in the aerobic phase. These strategies have been extensively studied in nitrifying reactors and are currently applied in real systems achieving biological carbon, nitrogen and phosphorus removal. In this work, we aim to demonstrate, through modelling and simulation, that the competition between nitrite reducers and nitrite oxidisers for nitrite, rather than kinetic selection plays a major role in NOB washout. Moreover, the results show that the occurrence of simultaneous nitrification and denitrification under "aerobic" conditions is very helpful for the nitrite pathway obtainment and for a more efficient COD utilisation.
Assuntos
Reatores Biológicos , Simulação por Computador , Modelos Teóricos , Nitritos/metabolismo , Eliminação de Resíduos Líquidos/métodos , Aerobiose , Nitritos/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/metabolismo , Purificação da Água/métodosRESUMO
Denitrifying phosphorus accumulating organisms (DPAO) are able to remove nitrogen and phosphorus simultaneously. The use of DPAO in EBPR systems results in a substantial saving on aeration cost and a lower sludge production when compared to anaerobic-aerobic EBPR systems. This process is usually studied in sequencing batch reactors (SBR) and monitored with off-line measurements. However, off-line monitoring implies low frequency data sampling and delay between sampling and obtainment of the results. For this reason, an online measurement such as titrimetry is strongly recommended to improve the daily management of the lab-scale SBR. This paper shows different applications of titrimetric measurements for on-line monitoring of DPAO lab-scale SBR cycles. The results demonstrate that titrimetry is a suitable tool for detecting the end of phosphorus release and carbon substrate depletion point in the anaerobic phase. Moreover, this paper proposes the indirect measurement of nitrate/nitrite uptake rate with titrimetric measurements, which allows the on-line estimation of its concentration during the anoxic phase. Therefore, titrimetry is an on-line measurement with a high potential to implement new control strategies in DPAO lab-scale SBR systems.
Assuntos
Reatores Biológicos/microbiologia , Sistemas On-Line , Titulometria , Anaerobiose , Bactérias Aeróbias/crescimento & desenvolvimento , Bactérias Aeróbias/metabolismo , Bactérias Anaeróbias/crescimento & desenvolvimento , Bactérias Anaeróbias/metabolismo , Carbono/metabolismo , Estudos de Viabilidade , Hipóxia , Nitratos/metabolismo , Nitritos/metabolismo , Nitrogênio/química , Nitrogênio/metabolismo , Fosfatos/química , Fosfatos/metabolismo , Fósforo/metabolismoRESUMO
The metabolism of polyphosphate accumulating organisms (PAOs) has been widely studied through the use of lab-scale enrichments. Various metabolic models have been formulated, based on the results from lab-scale experiments using enriched PAO cultures. A comparison between the anaerobic stoichiometry predicted by metabolic models with that exhibited by full-scale sludge in enhanced biological phosphorus removal (EBPR) wastewater treatment plants (WWTPs) was performed in this study. Batch experiments were carried out with either acetate or propionate as the sole carbon source, using sludges from two different EBPR-WWTPs in Australia that achieved different phosphorus removal performances. The results support the hypothesis that the anaerobic degradation of glycogen is the primary source of reducing equivalents generated by PAOs, however, they also suggested a partial contribution of the tricarboxylic acid (TCA) cycle in some cases. The experimental results obtained when acetate was the carbon source suggest the involvement of the modified succinate-propionate pathway for the generation of poly-beta-hydroxyvalerate (PHV). Overall, the batch test results obtained from full-scale EBPR sludge with both substrates were generally well described by metabolic model predictions for PAOs.
Assuntos
Fenômenos Fisiológicos Bacterianos , Modelos Biológicos , Fósforo/isolamento & purificação , Fósforo/farmacocinética , Esgotos/microbiologia , Biodegradação Ambiental , Simulação por Computador , Resíduos Industriais/prevenção & controleRESUMO
The objective of this study was to define an automatic control loop for the start-up of a high-strength nitrification system to achieve a rich nitrifying biomass from a poor nitrifying sludge by means of simulation tools. The used model considered the nitrification as a two-step model with substrate and non-competitive inhibitions. Two control strategies (on-off controller and proportional-integral (PI) controller) were designed, simulated and compared. The measured variable in the control loops was the sum of ammonium and nitrite concentrations in the effluent and the manipulated variable was the inflow. The objective in the optimisation of both controllers was to increase the inflow of the system as fast as possible without exceeding the maximum ammonium and nitrite concentrations allowed in the effluent. The optimised controllers parameters were used to simulate a 40 days start-up. The results obtained with both strategies were similar, although, the best strategy was the PI controller since it was less oscillatory and the biomass growth was slightly faster.
Assuntos
Modelos Biológicos , Nitritos/análise , Compostos de Amônio Quaternário/análise , Eliminação de Resíduos Líquidos/métodos , Bactérias Aeróbias/metabolismo , Reatores Biológicos , Simulação por Computador , Nitritos/metabolismo , Compostos de Amônio Quaternário/metabolismoRESUMO
Two-step nitrification models are generally calibrated using short-term respirometric batch experiments. Important discrepancies appear between model predictions and experimental observations just after the pulse addition since a fast transient in the OUR profile is experimentally observed. Acceleration of the OUR appears ongoing between the substrate addition and attainment of the maximum OUR value. Among the several phenomena that could contribute to this observation, the most probable cause is the limitation of reducing equivalents required for maximal ammonia monooxygenase activity at the time of substrate addition. Ignoring acceleration would result in large parameter estimation errors from respirometric batch experiments. This work proposes a simple methodology to successfully describe (not to explain) the acceleration phenomenon estimating only two parameters. This methodology consists of introducing a Gaussian-like expression in the model.
Assuntos
Amônia/metabolismo , Modelos Teóricos , Amônia/química , Cinética , Distribuição Normal , Oxirredução , Oxirredutases/metabolismoRESUMO
The enhanced biological phosphorus removal (EBPR) process is based on enriching the sludge with polyphosphate accumulating organisms (PAO) which are scarce in conventional non-EBPR wastewater treatment plant sludge. Hence, the start-up of EBPR systems (i.e. enriching the sludge with PAO) can be very slow and complex. A simulation study of a possible improvement of the start-up of an EBPR system in a sequencing batch reactor is presented in this work. The improvement is based on reducing the length of the aerobic phase so that it coincides with the depletion of orthophosphate from the medium. This improvement, though verified by simulation to be very successful, requires a good on-line orthophosphate sensor. To avoid this technical limitation, a link between oxygen uptake rate (OUR) measurements and orthophosphate presence is proposed. This link allows the control of the aerobic phase length with OUR as a measured variable and, consequently, a considerable improvement with respect to the conventional fixed aerobic phase length operation. An improvement of 95% in the ratio of PAO to heterotrophs and an increase of 30% in the final amount of PAO in sludge is achieved with this control strategy. The kinetic mod for simulations was a modification of the Activated Sludge Model 2d.
