Avaliação de aspectos da colmatação e descolmatação de sistemas alagados construídos de escoamento horizontal subsuperficial

• Ano de defesa: 2014
• Autor(a) principal: Miranda, Suymara Toledo
• Orientador(a): Matos, Antonio Teixeira de
• Banca de defesa: Monaco, Paola Alfonsa Vieira Lo , Rezende, Ana Augusta Passos , Fia, Ronaldo
• 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: Águas residuais - Tratamento biológico; Escoamento; Nitrogênio; Alagadiços; Suíno - Criação
• Palavras-chave em Inglês: Wastewater - Biological treatment; Flow; Nitrogen; Wetlands; Pig - Creation
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::ENGENHARIA AGRICOLA
• Link de acesso: http://locus.ufv.br/handle/123456789/3664

Constructed wetland systems of horizontal subsurface flow (CW-SSHF) are systems used in wastewater treatment. The main operational problem of these systems is the clogging of the porous medium, a phenomenon called "clogging". With this study, we aimed to characterize the composition of the material responsible for clogging the porous medium, CWs-SSHF and evaluate reverse clogging in these systems by adding nutrient solution nitrogen-based. To make possible this study, we used six CWs-SSHF that were completely clogged after being used in the treatment of swine wastewater. The operating conditions of these systems were called: CW-C (CW-SSHF 1 and CW-SSHF 4, uncultivated, ie controls); CW-T (CW-SSHF 2 and CW-SSHF 5 cultured with tifton 85 (Cynodon spp.)) and CW-A (CW-SSHF 3 and CW-SSHF 6 cultured with alternantera (Alternanthera philoxeroides)). The characterization of clogging material of porous medium from each experimental indicated that, for the most part, was composed of fixed solids (95, 84 e 82% in CW-C, CW-T e CW-A, respectively). It was observed that the cultivated CWs accumulated/produced more volatile solids that not cultivated systems, and the contribution of dead plant tissue may have been the main source of clogging in SACs-EHSS studied. To evaluate the effects of application of nutrient solution in the reverse clogging CWs-EHSS process, we carried out a comparison between sets of solids (total solids -TS, volatile solids - TVS and fixed solids -TFS) and readily oxidizable carbon (OCFO), before and after treatment, and performed hydraulic conductivity tests in saturated porous media, and monitoring the runoff in the gravel of the systems. The results indicated that the passage of the nutrient solution for 55 days, in the gravel of the SACs-EHSS provided reductions of 11 and 33%, respectively TVS content of fine material from clogging CW-T and CW-A. With respect to gross material, the reduction was even greater, being 33% for the CW-T and 62% for a CW-A. The hydraulic conductivity of saturated medium, made over the beds (1st, 2nd and 3rd thirds) before and after the passage of the nutrient solution in SACs, indicated, respectively, increases of 7%, 13% and 0,1% in CW-C, 21%, 11% and 7% CW-T. In the CW-A increase was evidenced only in 1st third (52%) and in the 2nd third (6%), while in the 3rd third there was a decrease in hydraulic conductivity in porous media. The reduction in the length of the gravel that had runoff nutrient solution occurred gradually, over time of treatment and were not observed any more runoff from the fourth week of the passage of the nutrient solution, the CW-C , and from the fifth week, the CW-T. In the CW-A, despite 72% reduction was observed in the seventh week of therapy, did not occur during the evaluation period, cessing, altogether, the runoff in these beds. Based on the results obtained, it was found that the passage of the nutrient solution based nitrogen contributed to reduction in surface runoff in the gravel, having been the reduction in the concentration of dead organic material present in the superficial layers, one of the main factors for this decrease.