The combination of advanced oxidation processes (AOPs) and electrochemical process is gaining growing popularity for use in wastewater treatment. The present work explores for the first time, treatment of leachate wastewater from landfill waste using a combination of sonication (US), ozonation (O-3) and electrocoagulation (EC) process expressed by % color removal, % Chemical Oxygen Demand (COD) removal and its associated electrical energy consumption. The results revealed that, the combined process (US/O-3/EC) is highly successful in the treatment of leachate wastewater from landfill in terms of % color removal (100 %) and % COD removal (97.50 %) with low electrical energy consumption (8kWhr/m(3)) than the other hybrid and single process such as O-3/EC, US/EC, US/O-3 and EC, O-3, US. The influence of different process parameters such as electrolyte concentration (1.50-7.50 g/L), current density (1.25-7.50 A/dm(2)), initial effluent pH (2-11), COD concentration (2000-6000 ppm), O-3 production (0.75-3.75 g/hr) and sonication power (20-100 Watts) were studied on the efficiency of pollutant removal evaluated by reduction of % color and % COD and electrical energy consumption using hybrid US/O-3/EC process. Overall, the analysis clearly showed that the approaches to integrated treatment technologies could synergistically remove the pollutant from the wastewater. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.