ABSTRACT This study aimed to fit mathematical models to whey foam drying processes in different air temperature conditions, to determine the effective diffusion coefficient and to obtain the activation energy. For foam formation, 5.0% Emustab® was added to the serum in mass and subjected to stirring in a domestic shaker for 15 min. After, it was spread onto trays to form a thin layer of about 1 cm in which the drying conditions were: 40, 45, 50, 55 and 60 °C, 5.6 m s-1 and 60%. The Logarithm and Midilli models describe the kinetics of serum foam drying; the effective diffusion coefficient increased with the elevation of drying temperature and activation energy of 50.84 kJ mol-1.

RESUMO Neste estudo, teve-se por objetivo avaliar a remoção de fósforo e obter coeficientes cinéticos em sistemas alagados construídos (SAC) utilizados no tratamento das águas residuárias da suinocultura (ARS), sob diferentes taxas de carregamento de fósforo (TCP). Para isso, foram utilizados oito tanques de 2,0 × 0,5 × 0,6 m. Em SAC3, SAC5, SAC7 e SAC9, foi plantado o capim tifton-85 (Cynodon spp.) e, em SAC2, SAC4, SAC6 e SAC8, foi plantada a taboa (Typha latifolia). As TCP médias aplicadas foram de 6,2 (SAC2 e SAC3), 12,4 (SAC4 e SAC5), 17,5 (SAC6 e SAC7) e 21,5 kg.ha-1.d-1 (SAC8 e SAC9). As eficiências de remoção de fósforo variaram entre 65 e 78%, valores que podem ser considerados satisfatórios, visto que a remoção de fósforo total nesses sistemas é baixa e varia entre 40 e 60%. Em relação aos ajustes de modelos cinéticos, verificou-se que o de primeira ordem não se ajustou bem aos dados obtidos neste trabalho, enquanto os de Brasil et al. (2007) e Kadlec & Wallace (2008) proporcionaram bom ajuste e descreveram com precisão a cinética de remoção de fósforo nos SAC avaliados, apresentando R2 superior a 90%.

ABSTRACT The objective of this study was to evaluate phosphorus removal and to obtain kinetic parameters in SACs used in the treatment of swine wastewater (ARS), under different phosphorus loading rates (TCP). For this, eight tanks of 2.0 × 0.5 × 0.6 m were used. SAC3, SAC5, SAC7, and SAC9 were planted with Tifton-85 bermudagrass (Cynodon spp.) and SAC2, SAC4, SAC6, and SAC8 were planted with cattail (Typha latifolia). The average TCP applied were 6.2 (SAC2 and SAC3), 12.4 (SAC4 and SAC5), 17.5 (SAC6 and SAC7) and 21.5 kg ha-1 d-1 (SAC8 and SAC9). The efficiency of phosphorus removal ranged between 65 and 78%, values which can be considered satisfactory, since the removal of phosphorus in these systems is low and ranges between 40 and 60%. Regarding adjustment of the kinetic models, it was found that the first order model did not fit well to the data obtained in this work, while the models of Brasil et al. (2007) and Kadlec & Wallace (2008) provided good fit and accurately described the kinetics of phosphorus removal in the evaluated SACs, with R2 greater than 90%.