Treatment of the dairy industry wastewater in constructed wetland systems cropped with forages / Tratamento de Água Residuária de Laticínios em Sistemas Alagados Construídos Cultivados com Forrageiras

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Taking into account the lack of information on the dimensioning, construction and operational methods, as well as the efficiency of the Constructed Wetland Systems (SACs) in purifying the dairy industry wastewater, this study was carried out to evaluate the influence of either the cropped vegetative species and average organic load applied in each unit area (TCOs) upon the performance of the pilot-systems. Each SAC consisted of one waterproof tank measuring 0.40 x 0.73 x 3.00, infilled with crushed stone (zero), 0.5% longitudinally basic declivity, and 0.33m filtering bed depth. The affluent of the SACs was subsuperficially flowing at an average flow of 60 L d-1 and hydraulic residence time of 4.8 days. The control treatment consisted of one SAC without vegetation (SV) to which a TCOs of 130 kg ha-1 d-1 BOD was applied, whereas in other SACs either cropped with elephant grass, Napier cv. (Pennisetum purpureum) and those cropped with grass tifton 85 (Cynodon spp.) the following TCOs were applied: 66, 130, 190, 320 and 570 kg ha-1 d-1 BOD. To evaluate the performance of those systems, six samplings of both affluent and effluent waters of each SAC were obtained during the experimental period, in order to measure the electric conductivity (CE) and pH as well as to quantify the concentrations of BOD, COD, ST, SST, Total-N, Total-P, K and Na. The aerial biomass of the vegetative species were also removed in order to quantify the green matter, dry matter and the concentrations of Total-N, Total-P, K and Na in the vegetal tissue. In general, both vegetative species showed a good adaptation to the systems, relative to the substrate saturation condition and the different TCOs applications. The systems showed to be efficient in removing BOD, COD, SST, ST and nitrogen, but were nonefficient in the removal of potassium and sodium. Although the results of this research are preliminary, they showed the Constructed Wetland Systems can be appropriate to the treatment of dairy industry wastewaters.

ASSUNTO(S)

Águas residuárias wastewater indústria de laticínios engenharia de agua e solo wetlands dairy products industry alagadiços

ACESSO AO ARTIGO

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