Luiz Alberto Ribeiro Mendonça

Contaminacao de pocos tubulares em Juazeiro do Norte-CE

A interacao do riacho dos Macacos e de uma bateria de pocos, na sua vizinhanca, em Juazeiro do Norte-CE, foi avaliada segundo parâmetros fisicos, quimicos e bacteriologicos. Foram realizadas tambem analises de oxigenio-18 a fim de avaliar a mistura de aguas subterrâneas com aguas superficiais. Verificou-se que o riacho dos Macacos, na maioria dos parâmetros analisados, nao se enquadra em nenhuma das classes de aguas doces da Resolucao N° 357 do CONAMA e da Portaria N° 518 do Ministerio da Saude. Constatou-se que neste riacho e no lago da Timbauba a concentracao de coliformes totais e termotolerantes e extremamente elevada. Uma simulacao computacional do transporte advectivo do contaminante de particulas do rio para o aquifero com o modelo MODPATH/MOFLOW revela tempos minimos de transito do manancial superficial poluido ate os filtros dos pocos entre 15 e 100 dias. Considerando a meia vida dos coliformes em aguas subterrâneas de aproximadamente 8 dias e sua alta concentracao na agua superficial, contaminacao dos pocos de abastecimento e inevitavel.

Produção de sedimentos em microbacias hidrográficas semiáridas sobre manejos diferenciados

The aim of this study was to evaluate and compare the sedimentological behavior in two small rural watersheds in the semiarid Northeast of Brazil, examining the influence of human activity on the sediment yields. The studied area is sited in the Alto Jaguaribe basin, more precisely in the Iguatu County, Ceara State. The experimental area was composed of two small watersheds denominated B1 and B2. In watershed B1 a treatment (thinning) was applied, eliminating the plant species with diameters lower than 10 cm. The results showed that the Caatinga clearing practice did have an influence in changing the sediment yield during the first events. It was also found that the magnitude of previous events contributed to an increase in the sediment yields by the subsequent events as a consequence of the sediment deposit in the drainage network. The accumulated sediment yields reached at the end of the 2009 rainfall season values of 1.45 and 1.39 tons ha -1 year -1 for B1 and B2, respectively, with no significant difference at 5%. It was concluded that, even when the effect of treatment on the sediment yields at the beginning of the rainy season is measured, the total sediment yields was not changed by the adoption of clearing. Therefore, it is a management system that can be employed in the land use at semiarid regions.

Avaliação da capacidade de infiltração de solos submetidos a diferentes tipos de manejo

Inadequate vegetation and soil management leads to physical changes that affect aquifer recharge. The Araripe Plateau feeds an elevated number of springs on its northern slope; however, there are indications that their yield is decreasing. Through this research, it was studied the infiltration capacity of soils under different types of management. Soil samples from 21 sites were grouped into four groups. Group 1 represents areas of preserved vegetation, the others, anthropized ones. It was observed that soil moisture and infiltration capacity are linearly well correlated with organic matter; mean soil moisture during the dry season was significantly higher for Group 1 than for the other groups, even during the rainy season and anthropized areas show low organic matter contents, soil moisture, and infiltration capacity, indicating modifications in the soils structure that reduce aquifer recharge.

Respostas hidrológicas em pequenas bacias na região semiárida em função do uso do solo

The main goal of this study was to evaluate and to compare the hydrological behavior of small watersheds investigating the influence of the anthropogenic activities and the hydrologic responses due to these activities. The experimental area was composed of two small watersheds denominated B1 and B2. In watershed B1, a treatment (thinning) was applied, eliminating the species with diameters less than 10 cm. The experimental watershed B2 was not submitted to any treatment maintaing the original vegetation. In this investigation a total of 24 rainfall-runoff events were considered, corresponding to the 2009 rainy season as a whole. The results revealed that the thinning of the caatinga generated modifications in the runoff only in the initial rainy season. The growing of herbaceous vegetation attenuated the water flow and reduced the runoff in B1, promoting small changes in response to the applied treatment. There were, however, higher peak discharges in watershed B1 compared with the preserved watershed.

Septic tank combined with anaerobic filter and conventional UASB: results from full scale plants

Anaerobic digestion is an important alternative for domestic wastewater treatment, especially in warm climate regions. Two full-scale anaerobic schemes were investigated: septic tank combined with anaerobic filter (STANF) and conventional UASB reactors. Treated effluents from these systems were subjected to disinfection by chlorination. The operational performance of 56 full-scale plants (36 STANF and 20 UASB) provided a realistic view. Findings showed that the plants operated with low OLR (< 2.0 kg COD/m3.day). Despite this, the removal of organic material was below values suggested by the literature (around 60% for COD). A removal of 4.0 Log10 units of total coliform and E. coli can be reached with residual chlorine (RCL) of at least 2.0 Cl-Cl2/l. Although UASB plants have performed better, improvement of maintenance is needed in both treatment configurations.

MODIFICAÇÕES NAS PROPRIEDADES DOS SOLOS DE UMA ÁREA DE MANEJO FLORESTAL NA CHAPADA DO ARARIPE

The Araripe Plateau in the tropic semi-arid region is characterized by great environmental diversity. The Araripe National Forest and several forest management units (FMU) are located in this area with mostly red-yellow Oxisols. The goal of this study was to identify a basic indicator that could represent a set of physical, chemical and biological properties of soils of the Plateau. Multivariate analysis was used to indicate changes in soil properties of a FMU. Soil samples were analyzed in triplicate (0-20 cm layer), from 15 points of the FMU and four points of the National Forest. Nine soil properties were selected to characterize differences between preserved and exploited sites, including those in recovery phases. The results show that two principal components account for approximately 76 % of the variance of the data: the first indicator of biological, chemical and physical soil quality and the second indicator of soil compaction. Multivariate cluster analysis of the first principal component group showed the formation of three sub-groups: the National Forest sub-group and two sub-groups of the FMU in different recovery stages. The Tukey test (5 % significance) applied to the grouping of organic matter content of soils agreed with results from multivariate cluster analysis. This indicates that this organic matter can be used as main indicator of changes in soil properties for the study area.

Análise morfométrica e ambiental da microbacia hidrográfica do rio Granjeiro, Crato/CE

Abstract Human activity in the micro basin of Granjeiro river,in the township of Crato/ Cariri, Ceara causes excessiverunoff, producing sediment deposition in watercoursesand causing floods along the river. In this investigationwe try to understand the environmental impacts on thehydrology of the area through: (i) a morphometriccharacterization of the Granjeiro river micro basin andtwo adjacent ones, (ii) a comparison of themorphometric parameters for the three micro basins,(iii) an environmental evaluation of the Granjeiro microbasin and (iv) a correlation of environmental impactsand morphometric parameters. Morphometriccharacterization is made through parameters thatdescribe the geometry of the basin, its drainage systemand its relief. Environmental evaluation is based on thespot diagnoses. According to morphometry, theGranjeiro micro basin should be less floods prone thanthe outher two. However, antropic environmentalproblems invert this order transferring a higherincidence of floods to the first. In order to minimizeenvironmental impacts, actions through structural andnon-structural measures, in accordance with social-environmental local reality, are proposed.

Problemas de cálcio na água de abastecimento de Nova Olinda - CE

The township of Nova Olinda, south of Ceara, is supplied with waters from four deep wells exploiting a confined sandstone aquifer. Calcite and gypsum rock outcrop and are being exploited commercially in the watershed where three of the wells are located. Since 2006, public supply pipelines are damaged due to a sheet-like precipitation causing frequent obstruction of the pipes. In this investigation we used chemical analyses, physical chemistry, X-ray analyses and determination of the calcite saturation index - CSI for studying possible causes for the deposits identified, basically, as calcite. Calcium concentrations and CSIs indicate that the water disinfection process adopted increases the tendency of calcite precipitation due to calcium contained in the chemicals used.

Análise estatística multivariada aplicada em amostras de água subterrânea da região do Cariri, sul do Estado do Ceará

Na area constituida por parte dos municipios de Barbalha, Crato e Juazeiro do Norte, sul do Estado do Ceara, os recursos hidricos subterrâneos sao a unica fonte de abastecimento publico e privado e a superexplotacao ja e evidenciada na intermitencia da antiga rede de drenagem perene, hoje perenizada por lancamentos de esgotos. A evolucao quimica das aguas subterrâneas foi estudada identificando similaridades entre variaveis fisico-quimicas, discriminando as mais significativas, atraves da metodologia da analise estatistica multivariada para explicar possiveis processos responsaveis pela qualidade das aguas na area. A analise fatorial identificou tres componentes responsaveis por aproximadamente 85% da variância total; o primeiro como indicador da dissolucao dos minerais presentes na Formacao Rio da Batateira e Formacao Santana; o segundo e o terceiro fatores como indicadores de uma possivel mistura entre as aguas naturais do aquifero com aguas poluidas. A analise de agrupamento multivariada por componente, apresentou quatro grupos no fator 1 e dois grupos nos fatores 2 e 3, identificados por amostras com diferentes faixas de concentracoes. Na analise discriminante, as variaveis mais significativas nos processos responsaveis pela evolucao hidroquimica da area foram o Mg 2+ e K + , podendo estar relacionados a processos de troca ionica e intemperismo de feldspatos.

Desenvolvimento de equações Intensidade-Duração-Frequência sem dados pluviográficos em regiões semiáridas

Neste estudo foram feitas a validacao da metodologia de desagregacao de chuvas das isozonas e sua utilizacao no desenvolvimento de equacoes IDF (Intensidade-Duracao-Frequencia) para tres municipios da Regiao Metropolitana do Cariri, Ceara, desprovidos de pluviografos. Na validacao utilizaram-se dados de estacoes localizadas em zonas climatologicas distintas da Regiao Metropolitana do Cariri e de uma estacao localizada na mesma zona. As precipitacoes maximas diarias anuais foram ajustadas e testadas pelas distribuicoes de probabilidade de Gumbel, Log-Normal II-P, Log-Normal III-P, Gama II-P e Gama III-P. As intensidades de chuvas estimadas pelo metodo das isozonas apresentaram altos indices de concordância e desempenho de Willmott, quando comparadas com as estimadas pelas respectivas equacoes IDF. As precipitacoes maximas diarias anuais utilizadas na aplicacao do metodo das isozonas se ajustaram, respectivamente, as distribuicoes Gama III, Log-Normal II e Gama II; entretanto, verificou-se que outras funcoes podem ser utilizadas sem perda significativa na precisao das estimativas; esses resultados indicam a viabilidade da utilizacao do metodo das isozonas como alternativa na elaboracao das equacoes IDF em regioes nao monitoradas.