Tratamento de água residuária da suinocultura em sistemas alagados construídos: desempenho e modelagem hidráulica-cinética

• Ano de defesa: 2011
• Autor(a) principal: Ramos, Nilton de Freitas Souza
• Orientador(a): Borges, Alisson Carraro
• Banca de defesa: Monaco, Paola Alfonsa Vieira Lo , Fonseca, Sandra Parreiras Pereira
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Engenharia Agrícola
• Departamento: Construções rurais e ambiência; Energia na agricultura; Mecanização agrícola; Processamento de produ
• País: BR
• Palavras-chave em Português: Wetlands; Efluente agro-industrial; Ecotecnologia; Argila expandida
• Palavras-chave em Inglês: Wetlands; Agro-industrial effluent; Ecotechnology; Expanded clay
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::ENGENHARIA AGRICOLA
• Link de acesso: http://locus.ufv.br/handle/123456789/3598

Pig activity has been increasing in the last years and the main form of creation is in confinement barns. As a result, there has been an increase on generation of swine manure in small areas, which increases the environmental risk of activity. Under these conditions, the use of constructed wetlands (CWs) presents as an alternative to be studied, because it has a low-cost of implementation and it s easy to be operated. The objectives of this study were to evaluate the removal of pollutants from swine wastewater by CWs, the contribution of plants species for this, the hydrodynamic behavior in the CWs and the setting of mathematical models of first-order kinetics to determine the coefficients of organic matter degradation in the CWs. Three CWs was implanted, using expanded clay as a support media, one was cultivated with Polygonum punctatum (CWE), another was cultivated with Chrysopogon zizanioides (CWV) and one was uncultivated (CWC) used as a control. The system was installed on the Água Limpa Farm, countryside of Viçosa-MG. Each CW was composed of three units (troughs of high density polyethylene) in series, each unit having dimensions of 0.35 x 0.49 x 1.95 meters. The swine wastewater influent was deriving from a hybrid anaerobic reactor and had organic matter load average of 270 kg ha-1 d-1 COD. For a nominal hydraulic retention time (τ) of 3.21 days, we obtained the removal of COD, BOD, total N (NT) and total P (PT) over the experimental period, with average efficiencies of 80 , 85, 38 and 51% (CWC), 83, 89, 48 and 69% (CWE) and 80, 81, 36 and 45% (CWV), respectively. In the CW cultivated with Polygonum punctatum (CWE), we observed the best performance in the removal of pollutants. Based on dry matter, the productivity obtained was 2.79 g m-2 d-1 and 1.91 g m-2 d-1, the removal of the total N applied load was 1.54 and 1.01 % and total P was 0.81 and 1.19% for Polygonum punctatum and Chrysopogon zizanioides, respectively. In two samples collected along the length of CWs was observed: increase in pH, EC values decreased, reducing the turbidity concentration and the total Kjeldahl-N concentration decay along the systems length. To study the hydrodynamic, tracers were added in order to determine the degree of dispersion of pollutants within the CWs and the experimental retention time (τR). Observing τR, can be noted the reduction on the time retention to 3.12 days in the CWC, whereas in the CWE and CWV observed increased to 4.14 and 4.11 days, respectively. The dispersion value was high in all wetlands. The concentrations of COD along the length of the SACs were used to adjust the kinetic models that describe a first-order decay of organic matter over the CWs. The models that showed a better fit to the experimental data were the plug flow model with residual concentration, the model of continuous stirred tank reactor and the model of Shepherd et al. (2001).