Avaliação de sistema para monitoramento de gás amônia em galpões avícolas com ventilação negativa

• Autor(a) principal: Amaral, Maíra Freire Pecegueiro do
• Data de Publicação: 2007
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/3688
• topic: Qualidade do ar; Bem-estar animal; Monitoramento de gases; Air quality; Animal welfare; Gases monitoring; CNPQ::CIENCIAS AGRARIAS::ENGENHARIA AGRICOLA::CONSTRUCOES RURAIS E AMBIENCIA

The industrial growth and economical activities in the world contribute to the increase of gases and pollutant production that compromises the air quality. One of the main gases produced inside of broiler houses is ammonia and exposure to a high concentration of ammonia can cause serious damages to animal s and worker s health. Therefore, controlling ammonia concentration is extremely important for animal welfare. Also, the quantification of ammonia emission from animal houses is important in order to study environmental pollution caused by animal production, its contribution to inventories of gas emission, and must be understood if we are to reduce environmental impacts. However, instruments for continuous monitoring of ammonia gas are expensive, not portable and need instrumentation support. It is necessary to develop a simplified and cost effective instrumentation, in order to achieve a feasible system for ammonia gas monitoring in animal houses. Thus, the general objective of this research was to evaluate the efficiency of low cost equipment for continuous ammonia monitoring in animal houses with negative ventilation system. The evaluated equipment, denominated PMU (Portable Monitoring Unit), was developed by researchers of the University of Kentucky, Iowa State University and Pensylvania State University, United States. The research reported here was accomplished in two similar broiler houses, near the town of Madisonville, Kentucky, USA. Air samples were collected from three places in each house, denominated 1, 2 and 3, referring respectively to the place between two of the four sidewall exhaust fans used for minimum ventilation (related with the initial phase of the animals), and for moisture control, between other two minimum ventilation fans (related the phase of initial growth) and among the tunnel ventilation fans (related with the phase of final growth) and hot weather. The concentrations and emission values of ammonia obtained by the PMU equipment were compared to the values obtained by MAEMU (Mobile Air Emission Monitoring Unit) which was considered the reference in this study. Four different methods for computing hourly averages of ammonia concentration were evaluated based on the concentration reading directly from the PMU, considering that final concentration value and sampling intervals directly affect the computation of ammonia emission. The methods studied were denominated AT, A2, A4 and AMX, in which they were considered, respectively, all the values during a sampling period; values from last two minutes, excluding the last value; values from de middle four minutes; and the maximum concentration value. For comparison between instruments for ammonia emission monitoring, the final values of ammonia concentration were multiplied by the appropriate ventilation rate to obtain the ammonia emissions designated as BT, B2, B4, and BMX. Under the conditions in which this experiment was conducted and the results obtained, it can be affirmed that the four studied methodologies for ammonia concentration of PMU presented values similar to those by the reference instrument MAEMU. From the methodologies studied for PMU, those which best approximated results of MAEMU were methodologies AT and BT, for ammonia concentration and ammonia emission, respectively. The highest ammonia concentration level was found on the initial phase, and the highest ammonia emission rate level was found on the final growth phase. No influence of high levels of emission rate or concentration were found in the PMU accuracy. In conclusion, the evaluated PMU instrument proved to be an efficient alternative for continuous monitoring of concentration and emission of ammonia. However, its prediction should be adjusted according to the equations presented in this thesis.