ABSTRACT Removal of the organic load, cyanides and lubricating oils, from liquid effluents of a specific chemical industry is investigated, where the wastewater is characterised by a high value of the chemical oxygen demand (COD) and high content of oils and cyanides. Such an effluent is usually treated by the (coagulation/chlorination) technique which has numerous disadvantages, of which the cyanogen chloride evolution and the possible leakage of chlorine are known to be very dangerous for human being. In the present work the Fenton and Fenton – like processes were employed to remove the majority of organic matters, cyanides and oils. Experimental tests were conducted to determine the effectiveness and the optimum operating conditions for wastewaters. The treatment train was found to be capable of lowering the wastewater (COD) from 16660 mg/l to 333 mg/l by the Fenton process and to 800 mg/l by the Fenton-like one, Cyanides from 9.11 mg/l to 0.18 mg/l and to 1.17 mg/l, and oils from 32910 mg/l to 65.82 mg/l by using both methods. Kinetic studies showed that the reaction is first order for COD measurements and cyanide removal. The ratios of BOD5/COD values obtained indicate that both Fenton and Fenton like treatments can enhance the biological treatment since they can convert the pollutants to easily biodegraded compounds. Results proved that the Fenton process is much better than the currently used methods because of its safety, efficiency and low comparative costs.