Eficiência da remoção de DQO, surfactantes e de óleos e graxas totais na estação de tratamento de esgoto vila city na cidade de Paranavaí – Paraná / Efficiency of removal of DQO, surfactants and total oils and grease in the sewage treatment plant vila city in the city of Paranavaí - Paraná

Avaliar a eficiência dos processos em uma Estação de Tratamento de Esgoto (ETE) é um instrumento fundamental na busca de uma sociedade mais sustentável. Este trabalho procurou avaliar parâmetros menos comuns, mas muito importantes para o equilíbrio sustentável do corpo hídrico receptor deste efluente, ainda que tratado: a DQO (demanda química de oxigênio), os surfactantes e os óleos e graxas. Foram avaliadas as concentrações destes parâmetros em diferentes etapas do processo de tratamento de esgoto da ETE Vila City, na cidade de Paranavaí-PR com o objetivo de se verificar a eficiência dos processos utilizados no tratamento do esgoto para adequação das concentrações destes aos valores referenciados pela legislação brasileira de lançamento de efluentes na coleção hídrica. Os valores obtidos para concentração destes parâmetros no período estudado indicam: remoção de cerca de 73% na concentração de DQO; remoção de cerca de 30% na concentração de óleos e graxas; média de remoção de cerca de menos de 8% na concentração de surfactantes

Mathematical modeling of the head loss and of the turbidity and particles removal in up flow direct filtration

Este trabalho propõe a modelação matemática da perda de carga e da remoção de turbidez e de partículas na filtração direta ascendente baseada nos modelos que descrevem macroscopicamente o processo de filtração. Os modelos incluem o mecanismo de desprendimento de partículas do meio filtrante e a alteração da porosidade do material retido durante o processo de filtração. Foram propostos dois modelos: o monodisperso e o polidisperso. Tais modelos foram adaptados para a aplicação à filtração direta ascendente em material granular de areia grossa e pedregulho a partir de modelos para filtração descendente. Objetivou-se a identificação da influência do vetor gravitacional na parcela de eficiência por sedimentação gravitacional na proposição de modelos de eficiência inicial de remoção na filtração ascendente. Três concepções para quatro modelos de eficiência inicial de remoção foram propostas e aplicadas à filtração ascendente. Duas destas concepções foram adaptadas do original da filtração em aerossóis para escoamento ascendente e a outra a partir de modelos para escoamento descendente. Os resultados do modelo monodisperso apresentaram boa aderência aos dados experimentais obtidos da filtração ascendente em um sistema de dupla filtração mediante uma análise estatística com base nos valores dos coeficientes de correlação não linear. O modelo polidisperso também foi analisado, não tendo alcançado, entretanto, a mesma eficiência do modelo monodisperso. Os valores de eficiência inicial de remoção para a filtração direta ascendente calculados pela concepção proposta neste trabalho indicam razoável adequação aos modelos de filtração e apresentam-se coerentes e consistentes com os valores experimentais e com a teoria da trajetória.This work proposes mathematical models to predict the head loss, the turbidity and particles removal in up flow direct filtration based on the models that describe macroscopic filtration process. The models include the mechanism of particles detachment from the granular medium and the porosity change of the retained material during the filtration process. Two models were proposed: the monodisperse one and the polidisperse one. These models were used for up flow direct filtration in granular material of coarse sand and gravel based on down flow filtration models. The identification of the influence of the gravitational vector was aimed in the efficiency portion by gravitational sedimentation in the proposition of models of initial efficiency collector in the up flow filtration. Three conceptions of four initial efficiency collector models were proposed and applied to up flow filtration. Two of those conceptions were adapted from up flow aerosols filtration and another one was based on down flow models. The results of the monodisperse model presented good adherence to the up flow experimental data from a double filtration system by means of a statistical analysis with based on coefficients of non lineal correlation values. The polidisperse model was also analyzed, however, it did not provide the same efficiency of the monodisperse model. The initial efficiency removal values for the up flow direct filtration calculated by the proposed models indicated reasonable suitability to the filtration models and they come coherent and consistent with the experimental values and with the theory of trajectory analysis

Modelação da perda de carga na filtração direta ascendente em meio granular de areia grossa e pedregulho Modeling of the head loss in up flow coarse sand and gravel direct filtration

Compreender e quantificar os mecanismos relacionados à perda de carga e à remoção de partículas em um meio filtrante granular é de importância fundamental para o estudo do processo da filtração. Este trabalho apresenta o desenvolvimento dos modelos de perda de carga na filtração em meios porosos e a proposição da modelação matemática semiempírica da perda de carga para meios filtrantes limpos e do desenvolvimento do perfil de perda de carga ao longo do tempo de filtração a partir da equação de Ergun. Objetivou-se a determinação dos valores das constantes da equação de Ergun para meio granular de areia grossa e pedregulho. Alguns exemplos de aplicação dessa modelação matemática são também apresentados e discutidos pelos autores com base em dados experimentais obtidos em uma estação piloto de dupla filtração.<br>To understand and to quantify the head loss due to the particles removal in a porous medium has primary importance to filtration process study. This paper presents the development of the models of head loss used in the filtration in porous media and proposes a mathematical semi-empiric model for head loss in clean beds and head loss increasing profile during the filtration run length, by means of the Ergun equation. The goal was the determination of Ergun’s equation coefficients for granular material constituted of coarse sand and gravel. Examples of application of these mathematical modeling are also presented and discussed by the authors based on experimental data obtained in a double filtration pilot plant

Evaluation of effluent post-treatment by slow filtration and adsorption with activated carbon produced from spent coffee grounds in surfactant removal in sewage treatment

Environmental pollution is a worldwide concern, especially when caused by sewage dumping into water bodies. Many substances are present in industrial or domestic wastewater, causing contamination in superficial water collection. Surfactants stand out for being widely used both industrially and domestically. The use of detergents and many types of surfactants was increased during the Covid-19 pandemic period, a fact observed in the levels in the effluent sample analysis from a Sewage Treatment Plant (STP) - Vila City around 21 and 39 mg L-1 in this period. This work evaluated the surfactant concentrations in the primary and secondary treatment units of the Vila City STP, in the city of Paranavaí-PR.-Brazil. In addition, the use of a post-treatment by slow sand filtration and adsorption by activated carbon produced from spent coffee grounds in the complementary removal of surfactants was proposed. A mixed bed with sand and activated carbon columns was made on a pilot scale, and filtration/adsorption runs were performed simulating slow filtration with rates of approximately 15 m3 m-2 day-1. The parameters used for the efficiency removal evaluation in a pilot plant run were: turbidity (NTU) and surfactant concentrations. The removal of surfactant concentrations was about 9% and 7% in the Upflow Anaerobic Sludge Bed reactors (UASB-RALF) and in the secondary treatment, respectively, at the STP - Vila City units. In the post-treatment proposed by filtration/adsorption, bed columns on a pilot scale plant obtained a reduction of approximately 94% in terms of turbidity (NTU) and 95% in terms of surfactant removal

<b>Proposal for initial collection efficiency models for direct granular upflow filtration

Mathematical models of the filtration process are based on the mass balance in the filter bed. Models of the filtration phenomenon describe the mass balance in bed filtration in terms of particle removal mechanisms, and allow for the determination of global particle removal efficiencies. This phenomenon is defined in terms of the geometry and the characteristic elements of granule collectors, particles and fluid, and the composition of the balance of forces that act in the particle collector system. This type of resolution is well known as the trajectory analysis theory. Particle trajectory analysis by mathematical correlation of the dimensionless numbers that represent fluid and particle characteristics is considered the main approach for mathematically modeling the initial collection efficiency of particle removal in water filtration. The existing initial collection efficiency models are designed for downflow filtration. This study analyzes initial collection efficiency models, and proposes an adaptation of these models to direct upflow filtration in a granular bed of coarse sand and gravel, taking into account the contribution of the gravitational factor of the settling removal efficiency in the proposal of initial collection efficiency models