Wine vinasses treatments by ozone and an activated sludge system in continuous reactors

In this work wine vinasses have been treated separately by means of a chemi cal ozonation and a biological aerobic degradation in an activated sludge s ystem, and later by means of a combined process which consisted of an aerob ic pretreatment followed by an ozonation treatment, in continuous reactors in all cases. In the ozonation experiments, the hydraulic retention time an d the ozone partial pressure were varied leading to substrate removals in t he range 4.4-16%, with increases in this removal when both operating variab les were increased. A kinetic study, which combines mixed flow reactor mode l for the liquid phase and plug flow reactor model for the gas phase, allow s to determine the rate constant for the ozone reaction and the consumption ratio, which are k(O3) = 3.6 1/(g COD.h) and b = 22.5 g COD degraded/mol O -3 consumed. The aerobic degradation experiments were conducted in the acti vated sludge system with variations in the retention time and influent orga nic substrate concentration in the wastewater. A modified Contois model app lied to the experimental results leads to the determination of the kinetic parameters of that model: K-1 = 5.43 1/g VSS and q(max) = 6.29 g COD/(g VSS .h). Finally, the combined process reveals an improvement in the efficiency of the ozonation stage due to the previous aerobic treatment with increase s in the substrate removal reached and in the rate constant obtained, the l ast one being k(O3) = 5.6 1/(g COD.h).