Treating industrial wastewater represents a serious problem nowadays; it requires a strong understanding of the particular systems and (in most of cases) ad hoc solutions. This work describes the use of Fenton's reagent (reaction between H2O2 and Fe(II)) for removing total organic carbon (TOC) from a particular chemical laboratory's lab-scale batch reactor wastewater. Some operating variables (hydrogen peroxide and ferrous ion concentration, temperature and pH) were evaluated regarding final TOC removal. An economic optimisation was made by means of a second order polynomial model representing these variables' behaviour regarding TOC removal (0.94 R2). The highest experimentally reached TOC removal was 88.8% at 50 mg/L [Fe(II)]0, 50 mM [H2O2]0, pH=2.8 at 80ºC, while 53.9% was obtained in optimised conditions, i.e. 36 mg/L [Fe(II)] 0,45.5 mM [H2O2]0, pH=2.6 at 20oC. It was found that the Fenton process could achieve 41% removal, even in adverse conditions (pH close to 6). It was noted from the analysis that both H2O2 concentration and temperature had a powerful effect on organic matter degradation efficiency, as well as on total treatment cost.