Marcio Ricardo Salla

Estudo da autodepuração do rio Jordão, localizado na bacia hidrográfica do rio Dourados

O artigo avaliou a capacidade de autodepuracao do rio Jordao que considera as contribuicoes reais do corrego Brejo Alegre em periodo de estiagem e 2 (dois) cenarios que consideram as cargas poluidoras estimadas de ETE – Estacao de Tratamento de Esgoto e a baixa capacidade de diluicao do rio para a vazao critica Q 7,10 , atraves do modelo QUAL-UFMG. A simulacao na estiagem apresentou satisfatoria calibracao atraves do ajuste dos coeficientes K 1 e K d , evidenciando a prevalencia da desoxigenacao por demanda carbonacea sobre a nitrificacao e a importância da reaeracao natural no processo de autodepuracao. Apenas o parâmetro DBO nao respeitou os limites preconizados pela Resolucao CONAMA 357:2005, onde 78,9% de sua extensao ficaram fora da regulamentacao devido ao recebimento de cargas poluidoras do corrego Brejo Alegre. Quanto as simulacoes dos cenarios, uma populacao de 58.860 habitantes para o Cenario 1 e 114.000 habitantes para o Cenario 2 garantiriam a capacidade de autodepuracao, considerando-se as imprecisoes da metodologia de analise da DBO e que adotou-se uma vazao critica 2,6 vezes inferior a menor vazao medida no periodo de estiagem.

Viabilidade técnica de implantação de sistema de aproveitamento de água pluvial para fins não potáveis em universidade

Este artigo tem como objetivo analisar a viabilidade tecnica de implantacao de sistema de aproveitamento de aguas pluviais para fins nao potaveis em uma edificacao com salas de aula e anfiteatros na Universidade Federal de Uberlândia, no municipio de Uberlândia. Dois tipos de analise foram realizadas: sob o ponto de vista quantitativo, verificando se a quantidade de agua pluvial coletada supre satisfatoriamente a demanda por agua nao potavel; e sob o ponto de vista qualitativo, verificando se, apos o descarte dos primeiros milimetros de precipitacao, a agua pluvial coletada possui qualidade suficiente para atender a essa demanda. Os resultados indicam que a implantacao desse sistema e viavel do ponto de vista quantitativo, pois, durante a simulacao pelo Metodo Netuno, obtiveram-se volumes do reservatorio de acumulacao com intervalo de 7,9 m 3 a 18,2 m 3 para um potencial de economia de agua potavel entre 18,2% e 53,2%. Alem disso, os resultados qualitativos indicam que a implantacao desse sistema e viavel, pois, descartando-se os primeiros 2,5 mm de precipitacao apos o periodo de estiagem e implantando-se um sistema de retencao de solidos suspensos mais eficiente, todos os parâmetros analisados durante a pesquisa atendem as normas NBR 15527 (ABNT, 2007), NBR 13969 (ABNT, 1997) e Manual de Conservacao e Reuso da Agua (AGENCIA..., 2005).

VELOCITY AND CONCENTRATION OF BUBBLES IN OZONIZATION COLUMNS WITH CROSS SECTIONS OF DIFFERENT SIZES

The size of the cross section of an ozonization column influences its hydrodynamic characteristics, which, on its turn, has effects on phenomena that depend on the relative movement between gas bubbles and liquid. To observe the influence of the cross sectional area on gas concentration and bubbles velocity, two columns were used. The first column had a square cross section with side of 0.19 m and the second had a circular cross section with diameter of 0.10 m. The ascendant velocities of the bubbles and their concentration were measured in both columns and compared. The transversal spread of the plumes of bubbles was also quantified. The results show that the increase of the cross section of the column, in the proportion studied here, does not result in a similar increase of the cross section of the ascending plume of bubbles. Furthermore, the results of average velocities and concentrations obtained for the smallest cross section resulted independent of the liquid level in the column, while the results for the largest cross section showed to be dependent of this level. The ratio between the cross sectional areas of the larger and the smaller plumes of bubbles decreases for higher distances to the bottom of the columns.

Estimativa preliminar de vazões de cheias no Brasil usando curvas envoltórias de Creager

Hydrologic studies are essential for the design and safety of hydraulic structures. In the past, a number of empirical equations were developed to represent relationships between drainage areas and observed peak discharges. Although these empirical equations have not been used frequently to study peak discharges due to the use of more detailed and sophisticated analysis, they can be used to estimate reference values, especially in ungaged sites. The objective of this paper is to assess peak discharges observed in many regions in Brazil, estimate the 10,000-year discharges according the Guia para Cálculo de Cheia de Projeto de Vertedores from Eletrobrás and compare them to the Creager envelope curves. In this study we used the records of naturalized discharges for the period of 1931 to 2012, for 131 hydroelectric projects selected in the main river basins in Brazil, using the official data published by the Operador Nacional do Sistema Elétrico (ONS) for the Sistema Interligado Nacional (SIN). The results presented in this paper show that it is possible to use the Creager envelope curves as a preliminary estimate of the design floods in Brazil. Generally, values of the Greager C coefficient between 60 and 100 are recommended for a preliminary estimate of a range of maximum discharges within drainage areas bigger than 10,000 km2. The results can be used in the preliminary estimate of maximum discharges and 10,000-year discharges for sites with no data using C values obtained from areas with enough data in the same river basin and with similar physical characteristics.

Evaluation of the performance of image classification methods in the identification of vegetation

Orbital imaging techniques offer comprehensive coverage of different regions for numerous environmental and socioeconomic applications, revealing the spatial characteristics and land use of those regions. The advantages of remote sensing include its ability to record spatial distribution patterns, and spectral and temporal data over large regions. The objective of this research is to evaluate the performance of different multispectral image classification methods in the selection of general vegetation, based on a set of samples taken from a LandSat 8 image. The quality of multispectral images and their final classification is usually evaluated based on the Kappa index, which is used as the quality standard in many remote sensing software programs. The classification methods chosen for this study were Parallelepiped, Maximum Likelihood, Mahalanobis Distance, and neural networks. The most suitable classification was used as standard and the other images were compared with it to determine the degree of similarity ranking (IS1x), defined as the percentage of pixels classified differently from those of the standard image. The IS1x was determined using a Matlab routine involving pixel subtraction between images. The results indicate that probability distribution methods are more suitable for discriminating vegetation types than other methods, and that some band combinations should be chosen.

SENSIBILIDADE DE CARACTERÍSTICAS MORFOLÓGICAS NO COMPORTAMENTO DE PARÂMETROS DE QUALIDADE DA ÁGUA EM RIO DE PORTE MÉDIO

Due to the lack of historical water quality data in the country, many technical papers about the river self-cleaning capacity in lotic ambients estimate the biochemical reaction coefficients from empirical equations, which depend on morphological and hydraulic characteristics of the river channel, the quality of the watercourse and the quality of the effluent released in the river. This paper analyzes the sensitivity of some morphological and hydraulic characteristics such as longitudinal slope, cross-section geometry and roughness of the side walls and bottom of the channel, in the concentration change of DO and BOD in a medium-sized river in Minas Gerais Brazil. A reach of 33 km of the Uberabinha River in Triângulo Mineiro has been chosen because its surface water availability and quality are critical for Uberlândia’s water suply system. The simulations showed that (i) the variation of the channel cross-section causes the lowest sensitivity in the OD profile; (ii) the sensitivity in the OD profile is larger for the longitudinal slope and Manning roughness coefficient, which shows the importance of field work and not use of inaccurate techniques for the determination of these two characteristics; (iii) there were not significant BOD differences for the three morphological characteristics analysed. Keywords: Sensitivity analysis, morphological characteristics, self-purification, medium-sized river.

Percepções e avaliações do consumo de água em escolas públicas da mesorregião geográfica Triângulo Mineiro/Alto Paranaíba (MG)

To promote environmental sustainability it is urgent, in all segments of society, the review of how water consumption is done and, especially, the adoption of practices and technologies to make better use of this resource and decreasing waste. In public school units is frequent the inappropriate use and also loss of water by conservation conditions of hydro-sanitary systems. The paper presented here is conducted to question about how water consumption is conducted in public schools in the region of Triangulo Mineiro. The aspects studied were separated by sector (bathroom, kitchen, indoor and outdoor area), which included the identification of water consumption, the practical procedures for cleaning and maintenance and the habits of users. Understanding the main aspects related is taken as main reference to proposition of guidelines in environmental education projects for the water rational use.

AVALIAÇÃO DE SISTEMA DE LEITO DE DRENAGEM NO DESAGUAMENTO DO LODO DE ESTAÇÃO DE TRATAMENTO DE ÁGUA COM ÊNFASE NA INFLUÊNCIA DOS AGENTES EXTERNOS NA FASE DE SECAGEM

Este trabalho teve como objetivo a avaliacao do desempenho do sistema de Leito de Drenagem em escala reduzida no desaguamento de lodo de uma Estacao de Tratamento de Agua. Foram avaliadas as fases de drenagem e secagem do lodo, sendo que na fase de secagem os ensaios foram conduzidos em duplicata para investigacao da influencia de fatores climaticos no tempo de secagem. Para tanto foram conduzidos experimentos com tres Leitos de Drenagem, cada um com uma manta geotextil diferente, avaliados sob a aplicacao de tres distintas taxas de aplicacao de solidos. Uma vez escolhida a melhor taxa de aplicacao de solidos, foram conduzidos ensaios nos quais foi avaliada a influencia parcial dos agentes externos apenas na fase de secagem, removendo-se a protecao lateral de um dos leitos. Foram avaliados, portanto, tres mantas geotexteis em ensaios em duplicata considerando a influencia parcial ou nao dos agentes climaticos. Assim, para cada manta estudada foram montados dois leitos de drenagem, um com a protecao lateral e outro sem a protecao lateral, totalizando seis leitos de drenagem. As fases de drenagem e de secagem do lodo foram avaliadas com taxas de aplicacao de solidos de 1,75 kg∙m-2, 3,5 kg∙m-2 e 7,0 kg∙m-2. Na fase de drenagem foi avaliado o parâmetro turbidez e na fase de secagem foi observada a influencia das variaveis climaticas no desaguamento do lodo por meio da obtencao do teor de solidos. Ressalta-se que os Leitos de Drenagem foram protegidos da incidencia direta da chuva, ou seja, a influencia foi indireta. O efluente do drenado apresentou, logo no inicio de operacao do sistema, turbidez abaixo de 10 NTU e, ao final, proximo de 1 UNT e o lodo apresentou teor de solidos 50% maior para o LD sem protecao lateral (envoltoria). Palavras chaves: Estacao de Tratamento de Agua (ETA), Geotexteis, Lodo, Leitos de drenagem. ABSTRACT The aim of this work was to evaluate the performance of the System Draining Beds sludge dewatering in a Water Treatment Plant. Phase’s drainage and drying of the sludge were evaluated, and the drying phase assays were conducted in duplicate for investigation of the influence of climatic factors on the drying time. Both experiments with three Draining Beds, each with a different geotextile, evaluated under the application of three different application rates of solids, were conducted. Once chosen the best application rate of solids, trials were conducted in which the partial influence of external agents was assessed only at the stage of drying, removing the lateral protection of the beds. Therefore, there were evaluated three geotextile blankets trials in duplicate considering partial or none influence of climatic agents. Then, for each bed studied, two blanket drain were assembled, one with side protection and other without side protection, totaling six beds of drainage. The steps of draining and drying of the sludge were evaluated at application rates of 1.75 kg∙m-2, 3.5 kg∙m-2 and 7.0 kg∙m-2 of solids. In a drain phase, the parameter turbidity was evaluated and in the drying step the influence of climate variables were observed in the dewatering of sludge to the obtained solids. It is noteworthy that the Draining Beds were protected from direct impact of rain, i.e., the influence was indirect. The effluent drained presented, earlier in the system operation, turbidity below 10 NTU and, at the end, turbidity near 1 NTU and the sludge solids showed 50% greater for the LD without lateral protection. Keywords: Water Treatment Plants (WTP), Geotextiles, Sludge, System Draining beds.

CONSUMO DE ÁGUA E PERCEPÇÃO DOS USUÁRIOS SOBRE O USO RACIONAL DE ÁGUA EM ESCOLAS ESTADUAIS DO TRIÂNGULO MINEIRO

Among environmental subjects the necessity of rational practices and water savings is important in the containporaneous society. In the public schools the inadequate use of the water is frequent, as well as the existence of leakages in the hydraulical installations and the use of non-economic hydraulic equipments. This paper aims at evaluating the water consumption and perception index by the users concerning this natural resource in school. Specifically, factors were investigated in twelve public schools of the Minas Gerais State, located in the Triângulo Mineiro region. Through questionnaires, direct interviews and comments it was characterized the form as the water is used in the schools. Information was obtained for the calculation of water use perception index concerning its rational use, according to Ywashima (2005) methodology. It was observed some inconsistency between consumption indicator and perception index in the year 2011, possibly because of wrong data of monthly water consumption (error on hydrometer reading) and existence of leakages not detectable or error in the number of students in schools. In general, the water users have the knowledge of the attitudes to be employed to promote the water savings. Some actions for the rational use of water are proposed. Keywords: water consumption index, water rational use, perception index, public schools, Triângulo mineiro.

Transferência de massa gás-líquido em coluna de aeração

The present work is a study of the mass transfer gas-liquid from air bubbles into water, generated by a diffuser of air, in a column of aeration, changing the air flow from 400 L/h to 2000 L/h, the level of water from 0.50 m to 1.80 m, whose taxes of superficial application of air had varied of 3.1 L/m2.s to 15.4 L/m2.s. Several hydrodynamics characteristics were measured, such as the velocity range of the air bubbles and their diameter, fundamental to check the mass transfer coefficient that are in literature, by using a laser equipment for non-intrusive velocimetry. After of the study of the mass transfer, it was concluded that the air flow between 400 L/h and 800 L/h and the level of water of 1.80 m was the most efficient of mass transfer, guaranteeing for these measure, into of the column in study, most quantity of dissolved oxygen.