Utilização de lírio amarelo (Hemerocallis flava) em sistemas alagados construídos para tratamento de esgoto doméstico / Use of yellow lily (Hemerocallis flava) in construtect wetlands for treatment of domestic sewage

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The objective of the present study was to evaluate the performance of four constructed wetlands subsurface flow systems (CW), operated with different rates of application in the treatment of domestic sewage. The experiment was conducted at the Experimental Area for Treatment of Municipal Waste, Department of Agricultural Engineering, Federal University of Viçosa, in Viçosa - MG. The domestic sewage, after passing through preliminary treatment (sand box, oil and grease separator, sieve and mixing tank), and by primary treatment (septic tank), was directed to secundary treatment. In the CWs 1, 2 and 3, was applied, respectively, 44 kg.ha-1.d-1, 98 kg.ha-1.d-1 and 230 kg ha-1.d-1 of BOD. The SAC 4 received domestic sewage that passed only by prior treatment resulting in a rate of 395 kg ha-1.d-1 of BOD. In all CWs Hemerocallis flava (yellow lily) was used in all CWs to remove the domestic sewage depuration. To evaluate the performance of CWs cultivated with lily analysis were carried out on total suspended solids (TSS), biochemical oxygen demand (BOD5), chemical oxygen demand (COD), nitrogen, phosphorus, sodium, potassium, pH, redox potential, electrical conductivity, total coliform and E. coli in the inffluents and effluents of the CWs. Regarding to yellow lily plants, the production of dry matter and the concentrations of N, P, K and Na in the leaf tissue were quantified. In all CWs there were the predominance of the anoxic/aerobic environment. Had a tendency that the lowest rates of application provided higher efficiencies on removal of N, P, K and Na. Higher efficiencies in removal of total coliform and E. coli in CWs were obtained with higher hydraulic detention time (HDT) values. The CWs showed high efficiencies in the removal of BOD: 90.1%, 83.6%, 81.1% and 90.8% and COD: 72.1%, 63.7%, 72.2% and 70.0 % in CWs 1, 2, 3 and 4, respectively, given the patterns of releasing of effluents set by Deliberation Normative COPAM/CERH N 1 (MINAS GERAIS, 2008). The equation adjusted with the data from COD was obtained according to the model proposed by BRASIL et al. (2007a), C/C0 = exp (- 0.832.t0,324) with R2 = 0.977. It was concluded that the use of higher rates of application didnt cause problems in the development of lily, plants and also there were no significant differences in the removal of nutrients at different rates used.

ASSUNTO(S)

taxa de aplicação application rate flow systems escoamento matéria orgânica engenharia agricola organic matter

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