A combined technological scheme for purification of undiluted high-strength wastewater produced in the shale oil industry was proposed. The initial values of chemical oxygen demand (COD), biological oxygen demand (BOD7) and phenols in the studied pyrogenic wastewater samples were up to 45, 35 and 1 g/L, respectively. Furthermore, the wastewater had a high toxicity to indicator organism Daphnia Magna (EC50 = 0.34%) and caused inhibition of oxygen uptake rate (IC50 = 3.4%) and nitrification rate (IC50 = 0.7%) in activated sludge treatment. The combination of air stripping, coagulation-flocculation, batch distillation, activated sludge and the Fenton oxidation processes reduced all measured parameters more than 95%. Consequently, a treatment scheme applicable to pyrogenic wastewater was developed.