B shows the biomass concentration (VSS) in bioreactors
throughout operation. The addition of 12 mg/L rhamnolipid in the
feeding or directly into the reactor had no effect on the VSS
concentration, which remained virtually the same in both
bioreactors. Average VSS concentrations of 2068 241 mg/L and
2188 279 mg/L were obtained in Control and Test bioreactors,
respectively, with no significant difference in the Studentttest. The
increase of biosurfactant concentration in the Test reactor to
24 mg/L had an effect contrary to expectations, contributing to a
greater biomass growth. At this concentration, average VSS
concentrations of 2166 190 mg/L and 2469 287 mg/L were
obtained in the Control and Test bioreactors, respectively, with
significant difference in the Student t test. These values resulted in
an 11% increase in the sludge disposal (measured in mg TSS