Engenharia Agrícola
URI permanente desta comunidadehttps://locus.ufv.br/handle/123456789/11733
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Resultados da Pesquisa
Item Variação na pressão estática de ar insuflado em diferentes vazões específicas em colunas de material orgânico com diferentes estádios de degradação bioquímica(Acta Scientiarum. Agronomy, 2008-04) Silva, Nara Cristina Lima; Matos, Antonio Teixeira de; Sartori, Márcia Aparecida; Moreira, Débora Astoni; Barros, Renata Tâmara Pereira de; Luiz, Fátima Aparecida RezendePouco se sabe sobre as necessidades de potência do ventilador, com o tempo, na na compostagem do material em leiras estáticas aeradas. Objetivou-se, com a realização deste trabalho, ajustar curvas de variação na pressão estática do ar, quando forçado em pilhas de material orgânico em diferentes estádios de degradação bioquímica. Para a condução do mesmo, montou-se uma pilha de compostagem com bagaço de cana-de-açúcar (BC) e cama de frango (CF), preparando-se a mistura de forma a se obter uma relação C/N inicial de 30/1. O material foi revolvido a cada três dias, durante o primeiro mês e a cada cinco dias, nos dois meses posteriores. No BC, nas condições tal como foi utilizado na mistura, e no material da mistura BC + CF, nas condições em que se encontravam após 30, 60 e 90 dias de compostagem, foi medida a perda de carga, em 1 m de altura de coluna. Quanto maior a vazão específica de ar e o tempo de degradação bioquímica do material, maior foi o decréscimo na pressão estática do ar nele insuflado. O modelo de Shedd se ajustou bem aos dados experimentais, na faixa de vazão específica de ar investigada, podendo ser usado para predizer os gradientes de pressão estática no composto orgânico.Item Performance of constructed wetlands in the treatment of aerated coffee processing wastewater: Removal of nutrients and phenolic compounds(Ecological Engineering, 2012-12) Rossmann, Maike; Matos, Antonio Teixeira de; Abreu, Edgar Carneiro; Silva, Fabyano Fonseca e; Borges, Alisson CarraroGiven the scarcity of studies on the behavior of constructed wetlands (CWs) when operating with previously aerated wastewater, the objective of the present study was to evaluate the influence of artificial aeration and vegetation on removal of nutrients and phenolic compounds from coffee processing wastewater (CPW) treated in CWs cultivated with ryegrass (Lolium multiflorum Lam.) For this reason, CWs were constructed measuring 0.6 m × 0.5 m × 2.0 m (H × L × W) and filled with pea gravel to a height of 0.55 m. The experiment was carried out considering a completely randomized design (CRD). Each variant of the experiment was replicated 10 times for each one of two replicates, implying in a total of 20 replicates, and 4 CWs characterized as follows: (i) ryegrass cultivated systems operating with an aerated influent (aiCWc), (ii) non-cultivated systems operating with an aerated influent (aiCW*), (iii) ryegrass cultivated system operating with a non-aerated influent (CWc), and (iv) non-cultivated systems operating with a non-aerated influent (CW*). For oxygenation of the CPW which would be supplied as aerated CPW in two treatments, an aeration system was implanted in the storage tank, consisting of a submerged Sarlobetter S520 pump with a flow of 0.52 m^3 h^−1, a gravel filter and tulle. The CPW was applied at an average flow rate of 0.020 m^3 d^−1, corresponding to a hydraulic retention time of 12 days. Efficiencies of 69, 72, 30 and 72% were obtained for the removal of total nitrogen (NT), total phosphorus (PT), total potassium (KT) and total phenolic compounds (FT), respectively, in the aiCWc. Aeration resulted in improved efficiency of pollutant removal such as N, P and phenolic compounds. The cultivated plant species (L. multiflorum) influenced the removal efficiencies of total-N, total-P and total-K in the systems, however, the best results were obtained by means of combination of vegetation with artificial aeration. Artificial aeration does not totally compensate the absence of plants, suggesting that the role of plants goes beyond the addition of oxygen to the medium, permitting the development of a more active and diverse microbial community near the root zone.Item Resistance to forced airflow through layers of composting organic material(Waste Management, 2014-12-20) Teixeira, Denis Leocádio; Matos, Antonio Teixeira de; Melo, Evandro de CastroThe objective of this study was to adjust equations to estimate the static pressure gradient of airflow through layers of organic residues submitted to two stages of biochemical degradation, and to evaluate the static pressure drop of airflow thought the material layer. Measurements of static pressure drop in the layers of sugarcane bagasse and coffee husks mixed with poultry litter on day 0 and after 30 days of composting were performed using a prototype with specific airflow rates ranging from 0.02 to 0.13 m^3 s^−1 m^−2. Static pressure gradient and specific airflow rate data were properly fit to the Shedd, Hukill & Ives and Ergun models, which may be used to predict the static pressure gradient of air to be blown through the organic residue layers. However, the Shedd model was that which best represented the phenomenon studied. The static pressure drop of airflow increased as a power of the material layer thickness and showed tendency for decreasing with the biochemical degradation time of the organic material.