RESUMO
Poultry processing plants generate large amounts of wastewater in the many steps necessary to provide high quality and safe products. Carcass chilling is one of these steps, where the temperature of the carcass is reduced from 40°C to 4°C, for reducing the growth rate of microorganisms and affecting flavour, texture and appearance. In this operation, carcasses are continually displaced through a series of two tanks (called pre-chiller and chiller) filled with cold water, thus being responsible for a considerable amount of wastewater generation. This work aimed to regenerate the wastewater of the pre-chiller tank employing microfiltration (pore size 0.10 and 0.20â µm) and ultrafiltration (UF; MWCO 10 and 50â kDa) polymeric membranes in bench and pilot scales, with the final purpose of reuse. Membrane performance was evaluated in terms of the capacity of removing the contaminants and producing sufficient permeate flux in different working pressures. Bench-scale UF membrane presented the highest initial permeate flux of 112.1â L/m2h at 200â kPa. The four membranes tested presented good retention of microorganisms, with apparent rejection of up to 100%. Pilot-scale membranes presented better apparent rejection, with retentions above 99% for turbidity, apparent colour and fat content. Moreover, organic matter retention was also very high, up to 94% for chemical oxygen demand and 92% for total organic carbon. The use of membranes seems to be a promising approach for recycling and reuse of poultry pre-chiller wastewater.
Assuntos
Galinhas , Purificação da Água , Animais , Membranas Artificiais , Ultrafiltração , Eliminação de Resíduos Líquidos , Águas Residuárias , ÁguaRESUMO
The separation of Jatropha curcas oil from azeotropes of ethyl alcohol-n-hexane and isopropyl alcohol-n-hexane using ceramic membranes with different cutoffs (5, 10 and 20â kDa) is presented. The mass ratios of oil:azeotropes (O:S) studied were 1:3 for feeding pressures of 0.1, 0.2 and 0.3â MPa, and 1:1 for the feeding pressure of 0.1â MPa. Isopropyl alcohol was the best solvent for the membranes conditioning to permeate n-hexane (240â kg/m2â h). In the separation of J. curcas oil and azeotropes of solvents, both membranes showed oil retention and total flux decreases with time. Overall, the lowest decrease in the retentions was reached in the 5â kDa membrane, while the lowest decrease in the total flux was reached in the 20â kDa. In the separation of oil and ethyl alcohol-n-hexane azeotrope, the best retention at 60â min of the process was equal to 17.3â wt% in the 20â kDa membrane at 0.3â MPa and O:S ratio equalled to 1:3. In this condition, the total permeate flux was 17.5â kg/m2â h. Different retentions and permeabilities are provided when changing the O:S ratio, the feeding pressure and the molecular weight cutoff of membranes.