Paulo Armando Victória de Oliveira

Análise econômica da geração de energia elétrica a partir do biogás na suinocultura

The demand for alternative sources of energy has grown in recent years in line with the variation of petroleum prices coupled with the recent energy crisis. Through anaerobic digestion swine manure can be converted into biogas. In the present study it was evaluated the economic viability of using biogas as an alternative source for the production of electricity, for different periods of generation. The method used for the economic evaluation was the Net Present Value (NPV). The time of return on invested capital was also calculated taking into account the discount interest rate on cash flows. The study proved to be economically viable use of biogas from swine manure as a source for generating electricity. The increased demand for electricity in the property increases the Net Present Value and decreases the time required for return of the investment.

Avaliação da amônia emitida de camas sobrepostas e piso concretado utilizados na criação de suínos

Swine production in deep bedding appeared as an alternative to the excessive use of water in the activity, however the problem of emission of pollutant gases appeared, mainly ammonia. This research aimed at evaluating the amount of ammonia emitted by wood shavings and rice husks deep beds and concrete floor, compared to acceptable levels for swine production in beds, during December 2002 to April 2003, in Concordia, Santa Catarina State. Three constructions with dimensions of 12.0 x 10.0 m, divided in 4 boxes with 5.0 x 6.0 m were used, each with a total of 216 animals (Landrace X Large White). The evaluation of air quality was based on the quantification of the ammonia emission, daily measurements, at 10:00 a.m. and 2:00 p.m. The wood shaving bed presented better efficiency in the absorption of the wastes compared to the rice husk, which presented the lowest values of ammonia emission. In the concrete floor the highest values were observed for the gas. As such, the wood shaving bed is indicated as the most appropriate for the swine production in summer conditions for the South of Brazil. For the statistical analysis an entirely randomized experimental design, with 4 replicates for each treatment was used.

Concentração de macronutrientes e metais pesados em maravalha de unidade de suínos em cama sobreposta

The swine production industry in Brazil has been severely criticized due to pollution, mainly in water, that has been noticed in regions where swine production is concentrated. This fact puts in question the current production model. Deep bedding system for swine production appears as a promising alternative, because it reduces the risks of contamination by converting manure management from liquid to solid phase. Additionally, it makes possible the production of organic compost, which can generate extra income or can be applied in the same farm to implement an organic agricultural production. This study evaluated the increase of macronutrients, copper and zinc concentrations in wood shavings used as a substrate in four stalls during a period when 8 groups of 70 animals were raised. Each stall had animals installed during 35 days, according to their age of entrance (nursery = 21, S1 = 56, S2 = 91 and S3 = 126 days). Results have shown that average concentrations of nutrients in beds are in compliance with legislation for simple organic fertilizer. The concentration of zinc in the nursery bed was about 5 times higher than other stalls, which shows the influence of diet on the composition of the compost.

Reduction emissions of CO2, CH4 and H2S through composting of swine manure

In conjunction with the development of technologies for the production of swine meat, a strong exploration and degradation of the environment occurred and the activity became a source of pollution in the producing regions. Therefore, there is a need for alternative technologies that minimize the pollutant potential of the current system of production. The proposed work was to analyze and to compare the emission of carbon dioxide (CO2), methane (CH4) and hydrogen sulfide (H2S) between the management of swine manure in solid form (composting) and liquid manure (deep pit), and assess the efficiency of the process of composting through the physical and chemical parameters. The test was implemented in the experimental field of Embrapa Suinos e Aves, located in Concordia (SC). The results have showed that composting reduces 7 times the CH4 emission comparing to deep pit, and emission of CO2 represented 78.5% of total mineralized carbon. Considering that the emission of H2S was significant only in the management of waste in liquid form, then management of waste in solid form can reduce the environmental impacts, which tends to be beneficial in terms of mitigation of greenhouse effect and may contribute to the reduction of odors.

Seasonal Influence in the Performance of Growing and Finishing Pigs Raised in Deep Bedding System in South of Brazil

Deep bedding is an alternative housing system that has some economical and environmental advantages compared with conventional buildings. However, there are some research questions that need to be answered, most of them related to animal health and feed conversion. This work evaluated during one year, a deep-bedded facility for the production of pigs in growing and finishing phase. The building was divided into three pens with different dimensions in order to supply an appropriate area per animal as the pigs grew. The sanitation statuses of the animals placed in each group were previously evaluated to reduce the risk of infections or diseases introduction. After one year (8 groups of 70 animals), samples of the bed were collected and analyzed to assess their potential as organic fertilizer. The statistical analysis of the results demonstrated that there was a smaller proportion of gastric ulcers and death loss in animals raised in winter than in summer. On the other hand, although numeric differences were detected, it was not possible to conclude that there are differences between summer and winter in the average results found for daily weight gain, feed conversion, pneumonia index, progressive atrophic rhinitis, and paracheratosis. For lymphadenitis, it was not possible to find any correlation between disease occurrence and deep bedding system. At the end of the experiment, the bed contained high levels of macronutrients (N, P, K), but an additional period of composting is recommended to complete the stabilization, reduce humidity, and turn the material into a suitable product for application as organic fertilizer.

Fator de emissão de metano em depósitos abertos utilizados para armazenar dejetos suínos no Sul do Brasil

The objective of this work was to contribute to the establishment of a baseline for the methane emission factor for the management of swine manure, considering the current practice of raw manure storage in two open deposits in parallel, in Southern Brazil. Methane (CH4) emissions were continuously measured in three PVC tanks of 3 m3, during 180 days, in the summer. As the content of volatile solids of pig slurry ran out in approximately 130 days, the CH4 emission factor was calculated as B0= 0.48 m3 kg-1 VS. Although this value is higher than the B0 estimated by Intergovernmental Panel on Climate Change for Latin America (0.29 m3 kg-1 VS), it is in agreement with the B0 estimated for developed countries (0.45 and 0.48 m3 kg-1 VS, for the US and EU, respectively). The graphic of accumulated CH4-C emission x time fitted a sigmoidal, kinetic model (r2= 0.998) that showed a good correlation when tested with the emission data collected from a slurry deposit, under field conditions, in winter. This suggests that the model reproduces the CH4 emission kinetics in the region. By applying the reviewed state law rules (retention time of 50 instead of 120 days), estimates by the sigmoidal equation show that it is possible to reduce in more than 80% methane gas emission.

The influence of the season of the year and of dilution on the development of swine manure and wood shaves co-composting

O presente trabalho buscou estudar a influencia de fatores relacionados ao manejo adequado dos dejetos de suinos (reducao da diluicao) e a sazonalidade, no desempenho da co-compostagem de dejetos de suinos com maravalha e na qualidade final dos compostos resultantes dos tratamentos. No primeiro estudo, foram utilizados dois tipos de dejetos de suinos: um diluido (2% Materia Seca - MS), tipico do manejo usualmente empregado no Brasil, e outro concentrado (6% MS). Os dejetos foram sendo incorporados a maravalha (6 L: 1 kg) no decorrer de 4 semanas. O desenvolvimento da compostagem foi acompanhado atraves dos monitoramentos das temperaturas no interior das pilhas e da emissao dos gases CO2 e CH4, durante 65 dias, incluindo o periodo da incorporacao. Os resultados demonstraram que o dejeto diluido nao fornece as condicoes minimas para o desencadeamento do processo, nao tendo sido observados o aquecimento da biomassa nem a respiracao aerobia ou anaerobia dos microrganismos apos o periodo de impregnacao, resultando em um composto de baixa qualidade. No segundo estudo, no qual se avaliou a compostagem no inverno e no verao, durante 85 dias, constatou-se que a troca de calor com o ambiente tem influencia na temperatura desenvolvida no interior das pilhas. As baixas temperaturas reduzem significativamente a atividade metanogenica na biomassa.