Arsenic, antimony and selenium in urban soils: potential risks for human health in urban gardening

The benefits of urban agriculture are many and well documented, ranging from health improvement to community betterment, more sustainable urban development and environment protection. On the negative side, urban soils are commonly enriched in toxic trace elements that have accumulated over time through the deposition of atmospheric particles (generated by automotive traffic, heating systems, historical industrial activities and resuspended street dust), and the uncontrolled disposal of domestic, commercial and industrial wastes. This in turn has given rise to concerns about the level of exposure of urban farmers to these elements and the potential health hazards associated with this exposure. Research efforts in this field have started relatively recently and have almost systematically omitted the influence of Sb and Se, and to a lesser extent of As, although all three have proven toxic effects.

Estudo da durabilidade de painéis de partículas de bagaço de cana de açúcar e resina poliuretana a base de óleo de mamona para aplicação na construção civil

O presente trabalho tem por objetivo avaliar o desempenho físico-mecânico e a durabilidade de painéis de partículas de bagaço de cana-de-açúcar com resina bicomponente a base de mamona (BCP) e compará-los com painéis de partículas de madeira comerciais (Medium Density Particleboard - MDP). Os painéis de bagaço de cana de açúcar foram fabricados com um teor de resina poliuretana a base de óleo de maona de 15%. O desempenho físico e mecânico dos painéis particulados foi analisado com base nas prescrições dos documentos normativos vigentes. Ambos os materiais foram revestidos superficialmente com resina poliuretana bicomponente à base de óleo de mamona. Avaliou-se a influência do tratamento das bordas na deterioração e no desempenho dos painéis. O acompanhamento das propriedades físico-mecânicas foi realizado antes e após os ensaios de envelhecimento por exposição natural durante 3, 6 e 12 meses, envelhecimento acelerado e de intemperismo artificial. Foi feita a avaliação, da suscetibilidade ao crescimento gerada pelo ataque de fungos emboloradores e apodrecedores nos materiais durante o envelhecimento natural e no ensaio acelerado. Foi realizada a análise colorimétrica para a identificação de mudanças de cor e brilho nos materiais após os ensaios de deterioração. Foram utilizadas as técnicas de densitometria de raios X, espectroscopia por infravermelho próximo (NIR). Os resultados obtidos indicaram a selagem lateral permitiu avaliar a superfície exposta do material permitindo a entrada da água pela superfície avaliando o efeito dos agentes de deterioração. A porcentagem de retenção para o Módulo de ruptura após o ensaio de envelhecimento por imersão em agua e secagem (APA D1) foi de 87% e 3% para BCP e MDP sem revestimento respectivamente e de 90% e 3% para BCP e MDP com revestimento. A porcentagem de retenção das propriedades mecânicas em ambos os submetidos à exposição natural diminuiu em função do tempo. Entretanto o porcentagem de retenção para os materiais BCP e MDP com revestimento superficial foi de 76% e 60% para MOR. A exposição natural mostrou que os fungos emboloradores foram predominantes em ambos os materiais. Ambos os materiais com revestimento superficial apresentaram entre 1-10% de colonização com um 70% de probabilidade. Revestimento de resina de óleo de mamona reduz o crescimento de fungos em ambos os materiais no ensaio acelerado. O perfil de densitometria permitiu analisar o processo de fabricação dos painéis e permitiu identificar a deterioração gradativa do ambos os materiais após os ensaios de envelhecimento. A intepretação mediante a analise de componentes principais (ACP) na aplicação do NIR comportou a classificação das características relacionadas a cada ensaio de deterioração de ambos os materiais sem revestimento superficial. Com base nos resultados deste trabalho, foram propostas contribuições para ajustes de metodologias para a avaliação da durabilidade e do desempenho físico e mecânico dos painéis particulados, tendo em vista a sua viabilidade técnica, em sistemas construtivos da construção civil.

Denitrification Enzymes-Based Biosensors: the Case of Haloarchaeal Enzymes

In the last two decades, the increase in the use of artificial fertilizers and the disposal of industrial wastes have been the main factors responsible for the progressive increase in nitrate and nitrite levels in groundwater and soil. A variety of analytical strategies have been developed for nitrate and nitrite detection but electrochemical biosensors, which are simple, cheap, easily miniaturized and suitability for real-time detection, are proved to be a powerful tool. Various types of biosensors based on the use of whole cells or on the immobilization of denitrification enzymes have been developed, but their use is limited in environmental analysis under extreme conditions such as brines, acidic or basic wastewaters, salted soils, etc. Extremophilic denitrifying microorganism are good candidates for the development of new nitrate and nitrite biosensors and, in particular, haloarchaeal based biosensors would have advantages over bacterial based biosensors since the microorganisms and the purified denitrifying enzymes tolerate a wide range of temperature and salinity. This work summarizes new highlights on the potential uses of denitrifying haloarchaeal enzymes to make enzyme-based biosensors.

Safety in wastewater works.

1st ed. (1944) published under title: Occupational hazards in the operation of sewage works.

Water & sewage works.

Vols. 76 include Reference and data section for 1929 (1929- called Water works and sewerage data section)

Dam break wave of thixotropic fluid

Thixotropy is the characteristic of a fluid to form a gelled structure over time when it is not subjected to shearing, and to liquefy when agitated. Thixotropic fluids are commonly used in the construction industry (e.g., liquid concrete and drilling fluids), and related applications include some forms of mud flows and debris flows. This paper describes a basic study of dam break wave with thixotropic fluid. Theoretical considerations were developed based upon a kinematic wave approximation of the Saint-Venant equations down a prismatic sloping channel. A very simple thixotropic model, which predicts the basic theological trends of such fluids, was used. It describes the instantaneous state of fluid structure by a single parameter. The analytical solution of the basic flow motion and theology equations predicts three basic flow regimes depending upon the fluid properties and flow conditions, including the initial degree of jamming of the fluid (related to its time of restructuration at rest). These findings were successfully compared with systematic bentonite suspension experiments. The present work is the first theoretical analysis combining the basic principles of unsteady flow motion with a thixotropic fluid model and systematic laboratory experiments.

An Investigation of the destruction of ion exchange resins

Ion exchange resins are used for many purposes in various areas of science and commerce. One example is the use of cation exchange resins in the nuclear industry for the clean up of radioactively contaminated water (for example the removal of 137Cs). However, during removal of radionuclides, the resin itself becomes radioactively contaminated, and must be treated as Intermediate Level Waste. This radioactive contamination of the resin creates a disposal problem. Conventionally, there are two main avenues of disposal for industrial wastes, landfill burial or incineration. However, these are regarded as inappropriate for the disposal of the cation exchange resin involved in this project. Thus, a method involving the use of Fenton's Reagent (Hydrogen Peroxide/soluble Iron catalyst) to destroy the resin by wet oxidation has been developed. This process converts 95% of the solid resin to gaseous CO2, thus greatly reducing the volume of radioactive waste that has to be disposed of. However, hydrogen peroxide is an expensive reagent, and is a major component of the cost of any potential plant for the destruction of ion exchange resin. The aim of my project has been to discover a way of improving the efficiency of the destruction of the resin thus reducing the cost involved in the use of hydrogen peroxide. The work on this problem has been concentrated in two main areas:-1) Use of analytical techniques such as NMR and IR to follow the process of the hydrogen peroxide destruction of both resin beads and model systems such as water soluble calixarenes. 2) Use of various physical and chemical techniques in an attempt to improve the overall efficiency of hydrogen peroxide utilization. Examples of these techniques include UV irradiation, both with and without a photocatalyst, oxygen carrying molecules and various stirring regimes.

The durability of cement bound minestone

The demand for road making materials continues to pressurise the supply of traditional good quality aggregates. Over the years, therefore, consideration has been given to alternative materials including industrial wastes. This thesis is concerned with potential use of Minestone, the by-product of coal mining, for the lower structural layers of pavement construction. Because of their clay like nature, Minestones do not merit consideration for such applications in an unbound state and, therefore, some form of stabilisation is necessary. Previous research has demonstrated that certain cement bound minestones, containing between 5 and 10 per cent cement, satisfy current Department of Transport requirements for use in pavement construction and, furthermore, they are not frost susceptible. However, doubts concerning the durability of cement bound minestones still remain. The thesis includes a review of both the cement and lime stabilisation techniques and also traces the origin and development of the methods used to assess the quality and durability of stabilised materials. An experimental study is described in which cement bound minestone specimens were subjected to a programme of tests which examined compressive strength, resistance to immersion, and resistance to freezing and thawing. The results of the tests were related to the properties of the raw materials. It was discovered that the response to cement stabilisation was governed mainly by the source of the minestone and, to a lesser degree, the cement content. It was also found that resistance in the durability tests was generally improved when the initial moisture content was raised above the optimum value. The result suggest that current methods for assessing cement stabilised materials are not appropriate to cement bound minestones. Alternative methods and criteria, based on volume change and retained strength following immersion and freeze-thaw tests, have been proposed. It is believed that these methods and criteria should also apply to other cement bound materials.

Business case development

Today, focus is shifting to creation of bio-energy, biofuel and bioproducts from cellulosic biomass derived from various sources, including existing and new crops and their residues, trees and forest residues, and municipal or industrial wastes. At present, biomass co-firing in modern coal power plants with efficiencies up to 45% is the most cost-effective biomass use for power generation. Due to feedstock availability issues, dedicated biomass plants for combined heat and power (CHP), are typically of smaller size and lower electrical efficiency compared to coal plants. The financial model discussed in the chapter is suitable for all countries both in the West and in the developing world. From the economic analysis given in the chapter it can be concluded that intermediate pyrolysis technology proves to be very effective in terms of product qualities of the oil produced and also the return on investment is around 4 to 5 years.

Avaliação da potencialidade de incorporação de um lodo de uma indústria de produtos de limpeza como adição mineral em concretos de cimento Portland

The generation of industrial wastes has been increased more and more in recent decades, motivating studies about a correct sustainable allocation and that also represents advantages for their generators. In this context, are included two companies of cleaning products niche, located in São José do Mipibu/RN, that produces industrial sludge at a sewage treatment plant, and that is the main approach of this research. Given this, it was studied the incorporation potentiality of this sludge as a mineral addition in cement matrix for concrete production due it high capacity of wastes immobilization inside this material, which are subsequently used in the company for making precast articles. Were added different sludge concentrations (5, 10, 15 and 20%) in a common trait (1: 2: 3), and evaluated their techniques and microstructural implications via workability test in fresh state and compressive strength, full porosity and scanning electron microscopy (SEM) in the hardened state. The results demonstrated the feasibility of the process both from a technical and environmental view as economical. All concretes produced with residue showed an increase of workability given the nature of the waste that had surfactants substances capable of adsorbing tiny particles of air into the batter. However, for all concentrations were obtained lower compressive resistances than standard concrete, with a reduction of 39% for samples with 20% of sludge. This are attributed mainly to an increase of porosity in the transition zone of these material, resulting from increased formation of ettringite at the detriment to the formation of other compounds, but which still allows the use of these for the manufacture of concrete articles with non-structural nature, such as precast floor. In addition, the water absorption and void ratio increased slightly for all samples, except the concrete with 20% of waste that has a reduction for the last parameter. Given this context, the recommended maximum level is 20%, constituting a significant proportion and able to allocate sustainably all waste generated in the industry.

Produção biológica integrada de hidrogénio e metano a partir de resíduos da indústria do biodiesel

Dissertação de Mestrado Integrado em Engenharia da Energia e do Ambiente

CRESCIMENTO INICIAL DE ACÁCIA-NEGRA COM VERMICOMPOSTOS DE DIFERENTES RESÍDUOS AGROINDUSTRIAIS

A utilização de vermicompostos de diferentes resíduos agroindustriais na produção de mudas de acácianegra pode ser uma alternativa de reutilização de resíduos e aumentar a produção de mudas. Assim, os objetivos deste trabalho foram avaliar o crescimento e a concentração de nutrientes em mudas de acácianegra, cultivadas em substratos com diferentes vermicompostos de resíduos orgânicos agroindustriais. Instalou-se em casa de vegetação 11 diferentes tratamentos: T1) vermicomposto de esterco bovino (EB); T2) vermicomposto de esterco ovino (EO); T3) vermicomposto de lodo de parbolização de arroz (LP); T4) tratamento controle (sem adubação); T5) tratamento controle com adução mineral (NPK); T6) mistura de EB e LP; T7) mistura de EO e LP; T8) mistura de EB e vermicomposto de resíduos de alimentos (RA); T9) mistura de EO e RA; T10) mistura de EB e vermicomposto de resíduos de frutas (RF); T11) mistura de EO e RF. Após 180 dias de cultivo em recipiente com capacidade de cinco litros, foram analisadas a massa seca e a concentração de nutrientes na parte aérea da acácia-negra, e a concentração de nutrientes no solo, após o cultivo. A adição do esterco bovino, bem como a mistura de esterco bovino e resíduos alimentícios favoreceram o incremento de matéria seca das plantas de acácia-negra. Os resultados mostraram que as concentrações de nutrientes nas plantas, com exceção de Fe e Mn, variaram com adição de vermicompostos no solo. Os tratamentos T3 e T6 elevaram as concentrações em P, N, Zn de Cu nas folhas de acácia-negra. Além disso, a adição dos vermicompostos ao solo aumentou a disponibilidade de nutrientes para as plantas, mesmo após o cultivo, especialmente com relação ao fósforo, potássio e magnésio, sendo uma alternativa viável e eficaz na produção de mudas, podendo substituir a utilização de adubação mineral.

Utilização de resíduos de catalisador (ECAT) e cinzas da casca de arroz (CCA) na elaboração de vidros silicatos soda-cal destinados a embalagem

Dissertação (Mestrado em Tecnologia Nuclear)