Luciano Matos Queiroz

Application of Anaerobic Digestion Model No. 1 for simulating anaerobic mesophilic sludge digestion

Improving anaerobic digestion of sewage sludge by monitoring common indicators such as volatile fatty acids (VFAs), gas composition and pH is a suitable solution for better sludge management. Modeling is an important tool to assess and to predict process performance. The present study focuses on the application of the Anaerobic Digestion Model No. 1 (ADM1) to simulate the dynamic behavior of a reactor fed with sewage sludge under mesophilic conditions. Parametric sensitivity analysis is used to select the most sensitive ADM1 parameters for estimation using a numerical procedure while other parameters are applied without any modification to the original values presented in the ADM1 report. The results indicate that the ADM1 model after parameter estimation was able to predict the experimental results of effluent acetate, propionate, composites and biogas flows and pH with reasonable accuracy. The simulation of the effect of organic shock loading clearly showed that an organic shock loading rate above of 35kg/m(3) day affects the performance of the reactor. The results demonstrate that simulations can be helpful to support decisions on predicting the anaerobic digestion process of sewage sludge.

Biological nitrogen removal over nitritation/denitritation using phenol as carbon source

A laboratory scale activated sludge sequencing batch reactor was operated in order to obtain total removal of influent ammonia (200; 300 and 500 mg NH3-N.L-1) with sustained nitrite accumulation at the end of the aerobic stages with phenol (1,000 mg C6H5OH.L-1) as the carbon source for denitrifying microorganisms during the anoxic stages. Ammonia removal above 95% and ratios of (NO2--N / (NO2--N + NO3--N)) ranging from 89 to 99% were obtained by controlling the dissolved oxygen concentration (1.0 mg O2.L-1) and the pH value of 8.3 during the aerobic stages. Phenol proved to be an adequate source of carbon for nitrogen removal via nitrite with continuous feeding throughout part of the anoxic stage. Nitrite concentrations greater than 70.0 mg NO2--N.L-1 inhibited the biological denitritation process.

Aplicação de processos físico-químicos como alternativa de pré e pós-tratamento de lixiviados de aterros sanitários

The aim of this article was evaluate the implementation of the ammonia stripping as a pretreatment for landfill leachate and the use of the coagulation-flocculation-sedimentation process for the removal of refractory organic compounds present in a landfill leachate pretreated in an activated sludge system. The rates of ammonia nitrogen removal ranged between 3.5 and 3.6 mg NH3-N.L-1.h-1in a lab scale reactor (working volume of 20 L) equipped with a mechanical stirrer and 3.2 and 3.3 mg NH3-N.L-1.h-1in a lab scale aerated column (working volume of 10 L). It was possible to achieve removals above 90% of refractory organic compounds (measured as apparent color) applied coagulant dosage about 400 mg Fe+3.L-1 and 400 mg Al+3.L-1.

Artificial Neural Network Modeling for Predicting Organic Matter in a Full-Scale Up-Flow Anaerobic Sludge Blanket (UASB) Reactor

The aim of this study is to propose a method for constructing Artificial Neural Network (ANN) models and evaluating their performance based on the application of two methods for the selection of the ANN topology: the dynamic division method (cross-validation or dynamics-split) (DDM) and the static-split method (SSM). The two methods are compared and applied to predict the amount of organic matter in an up-flow anaerobic sludge blanket (UASB) reactor operated at full scale. The performance of the ANN models was assessed through the coefficient of multiple determination (R2), the adjusted coefficient of multiple determination (Radj2

CRITÉRIOS ANALÍTICOS PARA LICENCIAMENTO AMBIENTAL DE ESTAÇÕES DE TRATAMENTO DE ESGOTOS: UMA CONTRIBUIÇÃO A PARTIR DE ESTUDOS DE CASOS NA BACIA HIDROGRÁFICA DO RIO SÃO FRANCISCO

R^{2}_{adj}

Post-treatment of sanitary landfill leachate by coagulation–flocculation using chitosan as primary coagulant

), and the root mean square error (RMSE). The comparison reveals that the DDM accurately selects the best model and reliably assesses its quality.

ANÁLISE DOS ENTRAVES À GESTÃO SUSTENTÁVEL DE RESÍDUOS DE TECNOLOGIA DA INFORMAÇÃO NA UNIVERSIDADE FEDERAL DA BAHIA

As estacoes de tratamento de esgotos (ETE) tem o seu planejamento, implantacao e operacao dependentes de apreciacao tecnica realizada no âmbito do Licenciamento Ambiental, ja que sao normativamente classificadas como atividades ou empreendimentos potencialmente poluidores. Este artigo propoe dois modelos analiticos, a saber, um referente a Licenca Previa e outro a Licenca de Instalacao, contendo os elementos de analise utilizados pelos orgaos ambientais durante a apreciacao dessas licencas. Ademais, e tambem apresentada a analise da pratica do orgao ambiental do estado da Bahia, por meio de quatro estudos de caso de Licenciamento Ambiental de ETE integrantes de Sistemas de Esgotamento Sanitario localizados na Bacia Hidrografica do Rio Sao Francisco. Constatou-se que a pratica do orgao ambiental nao incorpora os elementos propostos nos modelos. A analise da adequacao da ETE ao ambiente local mostrou-se limitada, evidenciando um baixo nivel de estudos dos principais impactos associados a essa tipologia. Observou-se, tambem, a falta de fundamentacao para a conclusao de deferimento ou nao das licencas, bem como das medidas propostas para minimizacao dos impactos negativos. A apreciacao realizada se mostra insuficiente para que a funcao primordial do Licenciamento Ambiental seja, de fato, cumprida. Como medida de aprimoramento, os resultados da pesquisa sugerem uma padronizacao minima dos elementos tecnicos a serem analisados durante o processo de licenciamento dessas unidades.

Prediction of organic matter removal from pulp and paper mill wastewater using an artificial neural network

Chitosan was chosen as an alternative primary coagulant in a complementary coagulation-flocculation treatment of sanitary landfill leachate with the aim of removing recalcitrant organic matter. In order to optimize the process conditions, central composite design and response surface methodology were applied. To evaluate the performance of the process using chitosan, we also carried out tests with aluminium sulphate (Al(2) (SO(4))(3).14 H(2)O) as coagulant. In addition, acute toxicity tests were carried using the duckweed Lemna minor and the guppy fish Poecilia reticulata as test organisms. The analytic hierarchy process was employed for selecting the most appropriate coagulant. Mean values of true colour removal efficiency of 80% and turbidity removal efficiency of 91.4% were reached at chitosan dosages of 960 mg L(-1) at pH 8.5. The acute toxicity tests showed that organisms were sensitive to all samples, mainly after coagulation-flocculation using chitosan. CE(50) for L. minor was not determined because there was no inhibition of the average growth rate and biomass production; LC(50) for P. reticulata was 23% (v v(-1)). Multi-criteria analysis showed that alum was the most appropriate coagulant. Therefore, chitosan as primary coagulant was not considered to be a viable alternative in the post-treatment of landfill leachate.

Modeling simultaneous carbon and nitrogen removal (SCNR) in anaerobic/anoxic reactor treating domestic wastewater

A gestao sustentavel de Residuos de Tecnologia da Informacao (RTI) em Instituicoes de Ensino Superior (IES) deve ser pautada na minimizacao da geracao dos residuos na fonte e na valorizacao dos mesmos. Neste trabalho, analisaram-se os entraves existentes, por meio de estudo de caso exploratorio, descritivo e propositivo, na gestao de RTI praticada pela Universidade Federal da Bahia. Alguns dos principais entraves identificados referem-se as exigencias legais para os procedimentos de desfazimento do RTI, as quais dificultam a minimizacao da geracao de tais residuos e a sua destinacao final adequada; a falta de procedimentos visando a reutilizacao por doacao, considerando o principio da responsabilidade compartilhada; ao nao atendimento dos requisitos legais por parte das Organizacoes da Sociedade Civil de Interesse Publico (OSCIPs), os quais impedem a doacao; e aos poucos requisitos ambientais exigidos nos processos de compra de equipamentos de Tecnologia da Informacao. No entanto, observa-se que com investimentos em planejamento, controle e educacao a maior parte desses entraves pode ser superada.

Aerobic, Anaerobic Treatability and Biogas Production Potential of a Wastewater from a Biodiesel Industry

AbstractThe Multilayer Perceptron Model was developed for predicting organic matter removal from pulp and paper mill wastewater. The original database covered a period of 1,427 consecutive days and contained the most frequently measured parameters. Three models were constructed by applying the technique of Principal Component Analysis, which selected principal components, discarded original variables and excluded possible outliers. The data were randomized and divided into training, validation and testing sets. The training algorithm was the Levenberg–Marquardt type, which is an adaptation of the back-propagation algorithm. The learning rate was 0.05, and the evaluation criteria used were the mean square error and the linear correlation coefficient. A marked difference was observed in the predictive performance when the organic matter load was used as an input. The model M4, which was built by discarding the two variables pH and EC, proved to be the most suitable and the simplest model obtained. However, ...