Abstract: The present disclosure describes a method for the revaluation of aqueous waste streams generated in the propylene oxide and styrene co-production processes. In particular, it discloses a method of reducing the organic contaminant load from a highly contaminated aqueous stream and recovery from said stream of organic compounds that may be recirculated or used as fuel in the co-generation of energy, and which comprises: acidification of said aqueous stream with inorganic acid at a pH less than 4.5; separation of the two resulting phases at a temperature greater than 40° C.; washing of the organic phase produced in the previous step with an aqueous solution of excess acid and separation of the two resulting phases.