Projeto de biodigestor para geração de bioenergia em sistema de produção de suínos: um estudo de caso da região de Icolo e Bengo - Angola

A tecnologia da biodigestão anaeróbia tem sido comprovada como uma das mais eficientes no tratamento dos dejetos de suínos, esta tecnologia, encontra-se num crescimento tímido em Angola facilitando assim uma poluição maior dos Rios, solos e o ar atmosférico, por falta de tratamento adequado da biomassa produzida por milhares de suínos existentes neste País. O emprego do biogás como fonte de energia para o funcionamento dos equipamentos ainda encontra limitações de ordem tecnológica e por falta de informação, organização e em muitos casos apoios tecnológicos e de instituições governamentais ou Não Governamentais. Este trabalho avaliou a viabilidade técnica, na implantação de Biodigestores na Região de Icolo Bengo em Angola. Foi estudada a implantação de Biodigestores, Modelo Indiano, na fazenda Menga assim como o potencial de geração de energia elétrica existente na produção de Biogás. O tratamento anaeróbio dos resíduos de Suínos como fonte renovável de energia, dentro de um conceito de desenvolvimento sustentável e de racionalização da produção sem agressão ao Meio-Ambiente também são referenciados mostrando que esta tecnologia pode ser apropriada como estratégia de conservação e uso eficiente da energia elétrica que é muito escasso em Angola. O emprego da biodigestão anaeróbia neste caso é possível e desejável, uma vez que contribui para preservação do Meio Ambiente, viabiliza os modernos sistemas de confinamento e reduz o custo da produção assim como ajuda na produção de energia elétrica e de fertilizantes. Um sistema integrado foi proposto e será aplicado na Fazenda Menga, como um dos projetos pioneiros em Angola.

Modelling soil erosion and transport in the Burrishoole catchment, Newport, Co. Mayo, Ireland

The Burrishoole catchment is situated in County Mayo, on the northwest coast of the Republic of Ireland. Much of the catchment is covered by blanket peat that, in many areas, has become heavily eroded in recent years. This is thought to be due, primarily, to the adverse effects of forestry and agricultural activities in the area. Such activities include ploughing, drainage, the planting and harvesting of trees, and sheep farming, all of which are potentially damaging to such a sensitive landscape if not managed carefully. This article examines the sediment yield and hydrology of the Burrishoole catchment. Flow and sediment concentrations were measured at 8-hourly intervals from 5 February 2001 to 8 November 2001 with an automatic sampler and separate flow gauge, and hourly averages were recorded between 4 July 2002 and 6 September 2002 using an automatic river monitoring system [ARMS]. The authors describe the GIS-based model of soil erosion and transport that was applied to the Burrishoole catchment during this study. The results of these analyses were compared, in a qualitative manner, with the aerial photography available for the Burrishoole catchment to see whether areas that were predicted to contribute large proportions of eroded material to the drainage network corresponded with areas where peat erosion could be identified through photo-interpretation.

Aproveitamento da água de chuva para fins não potáveis em uma atividade industrial: estudo de caso de uma edificação a ser construída, Rio de Janeiro, RJ

A escassez de água é um dos maiores desafios do nosso século. Parece mentira, uma vez que do planeta são ocupados por água. Essa abundância aparente leva-nos a considerar a água como um elemento barato, farto e inesgotável. Contudo, desse total, 97,5% são de água salgada, restando 2,5% de água doce, dos quais 1,75% formam geleiras, sendo, portanto, inacessíveis. E o pior: a exploração irracional da água doce armazenada nos lençóis subterrâneos, rios e lagos está ameaçando a magra fatia de 0,75% da água que pode ser usada pelo homem. Se a escassez e a poluição já são problemas concretos em muitos países, os quais já instituíram um efetivo gerenciamento de seus recursos hídricos, no Brasil a preocupação de cientistas e ambientalistas nem sempre é levada a sério. Afinal, temos mais de 12% da água potável do globo. No entanto, esta riqueza é extremamente mal distribuída: cerca de 80% estão na região amazônica; os 20% restantes distribuem-se desigualmente pelo país, atendendo a 95% da população. Cada vez que chove, milhões de litros de água, que normalmente deveram se infiltrar no solo correm pelos telhados e pelo asfalto até acabar em um rio poluído, sem nenhuma possibilidade de uso. E essa água pode e deve ser aproveitada, tanto para evitar enchentes quanto para economizar recursos hídricos e financeiros. Dessa forma, o objetivo deste trabalho foi o de estruturar um projeto de um sistema de coleta e aproveitamento da água de chuva, para fins não potáveis, para uma edificação a ser construída nas instalações de uma indústria de reparo e construção naval. Para tanto, foi apresentada uma metodologia cuja tecnologia para captação e aproveitamento da água de chuva baseou-se num levantamento bibliográfico e foi validada através da aplicação em um estudo de caso. Espera-se que este trabalho seja o ponto de partida para muitos outros dentro da indústria, procurando incentivar o aproveitamento da água de chuva para consumo não potável e criando assim uma consciência ecológica em todos os níveis da empresa, contribuindo dessa forma para a sustentabilidade.

Pollution and water quality control of the River Tejo. Report on a visit to Portugal, Sep 27th - October 10th, 1987

Fundamental changes in the management of water resources in Portugal are now evolving. Five regional organisations termed Administracaos de Regiao Hidrographic (ARH), will be created to manage water resources within their respective geographical areas. These areas will be catchment based. As a fore-runner to the implementation of the five ARH's a foundation project has been established within the Direcao-Geral do Recursos Naturais to examine the practical implications of the new system. This project has been divided into a number of sub-projects and complementary projects to include the Tejo complementary project. The Tejo complementary project is the focus of this report. The report is to advise on the role of biology in the proposed ARH, to establish priorities for biological studies within the present Projecto de Gestao Integrada dos Recursos Hidricos da Bacia Hidrografica do Rio Tejo (PGIRH/T) and to assist with the planning of laboratory facilities for biology at the new PGIRH/T laboratory at Alges, Lisboa.

Analysis of soils and sediments for organic pollutants

20 samples of soil or sediment (7 of which were predominantly sand) from various locations were received for analysis of their content of organic pollutants. These analyses were performed using a capillary column gas chromatograph equipped with an electron impact (E.I.) mass spectrometer as detector and using computerised data storage. In addition to the target compounds, the full scan data were examined to determine the composition of natural organic products and a series of diagnostic fragment ions was used to search for additional anthropogenic products. Organic-rich environmental samples are notoriously difficult to analyse for pollutant organics owing to the presence of high concentrations of many natural organic compounds. A single procedure for extraction and clean-up was adopted. It was designed for chlorinated aliphatic and aromatic hydrocarbons and other pesticides containing acidic functional groups and was based on published methods for the determination of organic pollutants in soils and sediments. 4 soils and 2 sands showed levels of one or two groups of PCBs slightly in excess of the detection limit, one sample showed a similar level of 2,4-D and 3 samples contained dieldrin at or just above the detection limit.

Applications of plasticity theory to selected problems in soil mechanics

Two topics in plane strain perfect plasticity are studied using the method of characteristics. The first is the steady-state indentation of an infinite medium by either a rigid wedge having a triangular cross section or a smooth plate inclined to the direction of motion. Solutions are exact and results include deformation patterns and forces of resistance; the latter are also applicable for the case of incipient failure. Experiments on sharp wedges in clay, where forces and deformations are recorded, showed a good agreement with the mechanism of cutting assumed by the theory; on the other hand the indentation process for blunt wedges transforms into that of compression with a rigid part of clay moving with the wedge. Finite element solutions, for a bilinear material model, were obtained to establish a correspondence between the response of the plane strain wedge and its axi-symmetric counterpart, the cone. Results of the study afford a better understanding of the process of indentation of soils by penetrometers and piles as well as the mechanism of failure of deep foundations (piles and anchor plates).

The second topic concerns the plane strain steady-state free rolling of a rigid roller on clays. The problem is solved approximately for small loads by getting the exact solution of two problems that encompass the one of interest; the first is a steady-state with a geometry that approximates the one of the roller and the second is an instantaneous solution of the rolling process but is not a steady-state. Deformations and rolling resistance are derived. When compared with existing empirical formulae the latter was found to agree closely.

Molecular biomarkers and toxic consequences of impact by organic pollution in aquatic organisms

Organic contaminants are readily bioaccumulated by aquatic organisms. Exposure to and toxic effects of contaminants can be measured in terms of the biochemical responses of the organisms (i.e. molecular biomarkers). The hepatic biotransformation enzyme cytochrome P4501A (CYP1A) in vertebrates is specifically induced by organic contaminants such as aromatic hydrocarbons, PCBs and dioxins, and is involved in chemical carcinogenesis via catalysis of the covalent binding of organic contaminants to DNA (DNA-adducts). Hepatic CYP1A induction has been used extensively and successfully as a biomarker of organic contaminant exposure in fish. Fewer but equally encouraging studies in fish have used hepatic bulky, hydrophobic DNA-adducts as biomarkers of organic contaminant damage. Much less is known of the situation in marine invertebrates, but a CYPlA-like enzyme with limited inducibility and some potential for biomarker application is indicated. Stimulation of reactive oxygen species (ROS) production is another potential mechanism of organic contaminant-mediated DNA and other damage in aquatic organisms. A combination of antioxidant (enzymes, scavengers) and pro-oxidant (oxidised DNA bases, lipid peroxidation) measurements may have potential as a biomarker of organic contaminant exposure (particularly those chemicals which do not induce CYP1A) and/or oxidative stress, but more studies are required. Both CYP1A- and ROS-mediated toxicity are indicated to result in higher order deleterious effects, including cancer and other aspects of animal fitness.

Understanding Micro- and Macro-Mechanics of Soil Liquefaction: A Necessary Step for Field-Scale Assessment

Liquefaction is a devastating instability associated with saturated, loose, and cohesionless soils. It poses a significant risk to distributed infrastructure systems that are vital for the security, economy, safety, health, and welfare of societies. In order to make our cities resilient to the effects of liquefaction, it is important to be able to identify areas that are most susceptible. Some of the prevalent methodologies employed to identify susceptible areas include conventional slope stability analysis and the use of so-called liquefaction charts. However, these methodologies have some limitations, which motivate our research objectives. In this dissertation, we investigate the mechanics of origin of liquefaction in a laboratory test using grain-scale simulations, which helps (i) understand why certain soils liquefy under certain conditions, and (ii) identify a necessary precursor for onset of flow liquefaction. Furthermore, we investigate the mechanics of liquefaction charts using a continuum plasticity model; this can help in modeling the surface hazards of liquefaction following an earthquake. Finally, we also investigate the microscopic definition of soil shear wave velocity, a soil property that is used as an index to quantify liquefaction resistance of soil. We show that anisotropy in fabric, or grain arrangement can be correlated with anisotropy in shear wave velocity. This has the potential to quantify the effects of sample disturbance when a soil specimen is extracted from the field. In conclusion, by developing a more fundamental understanding of soil liquefaction, this dissertation takes necessary steps for a more physical assessment of liquefaction susceptibility at the field-scale.