Aproveitamento de biomassa residual no semiárido para a produção de compostos orgânicos

A região semiárida nordestina abrange uma área de 106 km2 com características climáticas marcantes como a escassez e irregularidade das precipitações pluviométricas. Os sistemas de produção agrícola são predominantemente de pequena propriedade e sua sustentabilidade é afetada pela baixa fertilidade natural dos solos. O uso de biomassa residual para a produção de compostos orgânicos é uma alternativa importante para o desenvolvimento da região. Com isso, o objetivo desta dissertação foi avaliar o uso de diferentes biomassas residuais, como a poda de espécies vegetais arbóreas e estercos animais, como matérias-primas para a produção de compostos orgânicos. A presente dissertação foi dividida em dois capítulos, no primeiro avaliou-se o efeito da adição de diferentes podas vegetais na compostagem com esterco bovino e pó de rocha MB-4, no tempo de maturação e qualidade dos compostos orgânicos. Para isso, montou-se um experimento no pátio de compostagem na Fazenda Tamanduá PB, nos meses de janeiro a abril de 2008, com pilhas de compostagem de 100 kg no formato cônico em delineamento inteiramente casualizado com três tratamentos: T1: esterco bovino + poda de mangueira + MB-4; T2: esterco bovino + poda de jurema-preta + MB-4 e T3: esterco bovino + poda de algaroba + MB-4, com quatro repetições. Com os compostos orgânicos produzidos foi realizado experimento em casa de vegetação, com quatro tratamentos e cinco repetições, no Departamento de Energia Nuclear - UFPE para avaliar o acúmulo de nutrientes pelo milho. No segundo capítulo, foram avaliados as adições de biomassa de gliricídia, como fonte de N orgânico, e o MB-4 como fonte Ca e Mg na compostagem de podas de mangueiras com esterco bovino e seu efeito no tempo de maturação e qualidade final dos compostos orgânicos. Para isso, montou-se experimento no pátio de compostagem na Fazenda Tamanduá PB, nos meses de maio a agosto de 2009, com pilhas de compostagem de 100 kg no formato cônico em delineamento inteiramente casualizado com três tratamentos: T1: esterco bovino + poda de mangueira; T2: esterco bovino + poda de mangueira + biomassa de gliricídia; T3: esterco bovino + poda de mangueira + biomassa de gliricídia + MB-4 e T4: esterco bovino + poda de mangueira + MB-4, e quatro repetições. A fim de testar a qualidade dos compostos orgânicos produzidos realizou-se um ensaio em casa de vegetação no Departamento de Energia Nuclear UFPE, com cinco tratamentos e cinco repetições, utilizando a planta de milho como indicadora do acúmulo de nutrientes. Os resultados do primeiro capítulo indicaram que o tempo de maturação dos compostos orgânicos para os diferentes resíduos de podas vegetais, poda de mangueiras e algaroba foi de 90 dias, e o composto que apresentou os maiores teores médios totais de N, P, K, Ca e Mg foi produzido com poda de algaroba, esterco bovino e MB-4 e o maior acúmulo de nutrientes pela planta de milho em ensaio em casa de vegetação foi verificado quando adubado com composto orgânico produzido com poda de mangueira, esterco bovino e MB-4 . Os resultados do segundo capítulo demonstraram que a adição de biomassa de gliricidia e do pó de rocha MB-4 na compostagem de podas de mangueiras e esterco bovino não afetaram o tempo de estabilização dos compostos orgânicos. O composto orgânico que apresentou as maiores concentrações totais de N, P, K, Ca e Mg foi produzido com poda de mangueira, esterco bovino e biomassa de gliricídia e o maior acúmulo de N, P, K, Ca e Mg pela planta de milho em casa de vegetaçã

Determinação multiresíduo de pesticidas em água utilizando XAD-4 e florisil

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Determinação multiresíduo de pesticidas em água utilizando XAD-4 e florisil

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Energetic and Economic Analysis of Spineless Cactus Biomass Production in the Brazilian Semi-arid Region

The Brazilian semi-arid region is marked by a variable spatial-temporal rainfall distribution, concentrated over a 3 to 4 month season. Limited water availability is the main obstacle to the production of forage plants of C3 metabolism (such as corn and soybeans) and C4 metabolism (such as sugarcane), as well as livestock. To mitigate this forage supply, the spineless cactus (SC) has been cultivated in the region, producing high biomass amounts in this harsh environment. Recently, this remarkable capacity to produce biomass has drawn the attention of the renewable energy sector, supported by recent studies demonstrating the feasibility of its biomass as a raw material for bioenergy production. However, before moving to commercial scale, it is necessary to demonstrate that large-scale production has energy and economic viability for clean energy investors. Thus, the objective of this article was to analyze the energetic and economic viability of forage cactus cultivation systems in the Brazilian semi-arid region. The data used were extracted from the literature, based on forage production. For the energy evaluation, the energy balance was performed and the energy efficiency, energy productivity, specific energy, and net energy metrics were applied. The financial feasibility analysis used the Net Present Value (NPV) and Internal Rate of Return (IRR). The energy balance revealed that the SC cultivation is viable for biomass commercial-scale production, with an energy efficiency of 3.36, an energy productivity of 0.25 kg MJ−1, a specific energy of 13.5 MJ kg−1, and an energy balance of 127,348 MJ ha−1. For the economic aspect, considering an attractive minimum rate of return of 8%, production also proved to be viable, in a time horizon of three years. The Net Present Value and IRR metrics were USD 2196 and the IRR was 46%, respectively. The results found are important to encourage new investments in rural properties in the semi-arid region, and cultivation in new areas proved to be an efficient alternative from an energy and economic point of view, in addition to collaborating for the energy transition to sustainable sources and in the mitigation of regional environmental impacts

Energetic and Economic Analysis of Spineless Cactus Biomass Production in the Brazilian Semi-arid Region

The Brazilian semi-arid region is marked by a variable spatial-temporal rainfall distribution, concentrated over a 3 to 4 month season. Limited water availability is the main obstacle to the production of forage plants of C3 metabolism (such as corn and soybeans) and C4 metabolism (such as sugarcane), as well as livestock. To mitigate this forage supply, the spineless cactus (SC) has been cultivated in the region, producing high biomass amounts in this harsh environment. Recently, this remarkable capacity to produce biomass has drawn the attention of the renewable energy sector, supported by recent studies demonstrating the feasibility of its biomass as a raw material for bioenergy production. However, before moving to commercial scale, it is necessary to demonstrate that large-scale production has energy and economic viability for clean energy investors. Thus, the objective of this article was to analyze the energetic and economic viability of forage cactus cultivation systems in the Brazilian semi-arid region. The data used were extracted from the literature, based on forage production. For the energy evaluation, the energy balance was performed and the energy efficiency, energy productivity, specific energy, and net energy metrics were applied. The financial feasibility analysis used the Net Present Value (NPV) and Internal Rate of Return (IRR). The energy balance revealed that the SC cultivation is viable for biomass commercial-scale production, with an energy efficiency of 3.36, an energy productivity of 0.25 kg MJ−1, a specific energy of 13.5 MJ kg−1, and an energy balance of 127,348 MJ ha−1. For the economic aspect, considering an attractive minimum rate of return of 8%, production also proved to be viable, in a time horizon of three years. The Net Present Value and IRR metrics were USD 2196 and the IRR was 46%, respectively. The results found are important to encourage new investments in rural properties in the semi-arid region, and cultivation in new areas proved to be an efficient alternative from an energy and economic point of view, in addition to collaborating for the energy transition to sustainable sources and in the mitigation of regional environmental impacts

Potentialities and Impacts of Biomass Energy in the Brazilian Northeast Region

In Northeast Brazil, the use of biomass for energy generation is settled on traditional productive arrangements, such as a sugarcane production system in the humid Atlantic coastal area and firewood extraction from native tropical dry forests in the west. In parallel, substantial amounts of other biomass sources, such as residues from agricultural or urban processes, are still little used or wholly wasted, fudging the opportunity to generate new value chains based on these biomass sources. We hypothesize that using these non-traditional biomass sources to produce biofuels would significantly increase the regional bioenergy supply. In this context, this article discusses the potential for the production and use of biofuels and bioenergy in Northeast Brazil and its effects on regional development, which may be useful for both private actors and policymakers in the energy sector. The use of biomass sources for energy in the region is significant, reaching approximately 8.8 million tons of oil equivalent (toe) per year, emphasizing the already consolidated production of sugarcane and its derivatives. The use of all biomass resources in the Northeast region could supply around 4% of the Brazilian national electrical energy demand, with an environmental footprint of 0.055 tCO2eq per toe, which would contribute to reducing emissions from the Brazilian energy matrix generation. Regarding the spatial distribution of biomass sources, sugarcane prevails on the coast, firewood and livestock manure in the dryland area towards the west, and municipal solid waste is distributed throughout the region within urban areas. Different from what we expected, the potential energy recovery from municipal waste and animal manure would increase by only 17% the current bioenergy supply. In the future, since the majority of the region presents a semi-arid climate with limited rainfall, to increase the use of biomass as an energy source, there is a need to increase the supply of biomass sources with high efficiency in water use and good yields in drylands. For this, the cultivation and use of cacti and agave, for example, could contribute to making biorefineries viable in the region. Above all, public policies for harnessing bioenergy in NE Brazil must seek opportunities associated with the carbon/decarbonization economy, with studies being needed to assess the technical, economic, social, and environmental viability of future productive arrangements

Cotton Growth and Nutrient Uptake after Rock Phosphate, Gliricidia Prunings or Chemical Fertiliser Application in Soils of Semiarid Northeast Brazil

Several studies have demonstrated that organic fertilisers or ground rocks may be a viable alternative to industrialised chemical fertilisers in some agricultural systems. The present study aimed to compare the effects of ground phosphate rocks, gliricidia prunings and chemical fertilisers as nutrient sources to cotton (Gossypium hirsutum L.) cultivated in two types of soil (Fluvic Entisol and Oxisol) of the Brazilian semiarid northeast region. The experiment was conducted in a greenhouse at the Federal University of Pernambuco, in a completely randomised design with twelve treatments and four replications, consisting of three phosphate sources (MB-4 rock powder, Bahia rock powder and triple superphosphate), two nitrogen sources (urea and gliricidia) and a control without fertilisation. The aboveground biomass of cotton plants in the second growing cycle showed higher values of nitrogen with the combined use of gliricidia and MB4. The results indicated that the uses of green manure combined with natural phosphate may be a viable alternative to supply phosphorus and nitrogen to cotton plants in the Brazilian semiarid region. This can be a potential source of phosphorus and nitrogen in familiar agriculture and can replace mineral fertilisation