The present work has established the utility of ultrasound assisted interesterification process for the production of biodiesel and triacetin from WCO. The process can be a useful alternative to the more commonly used transesterification as it generates triacetin instead of glycerol which is an important additive to improve the properties of biodiesel particularly in cold conditions. The presented results are very important in the current context as it has focused on one of the cheaper synthesis routes for biodiesel production based on the use of waste oils with significant degree of intensification using ultrasound. Higher biodiesel yield has been observed in the case of ultrasonic technique as compared to the conventional method and also the properties of the synthesized biodiesel are better. The excess of reactants required is also lower as compared to the conventional routes and supercritical oxidation route which gives benefits in terms of lower separations costs. The work has confirmed for the first time that significant process intensification is obtained for the synthesis of biodiesel based on the interesterification approach. To summarize, the main advantages offered due to the use of sonochemical reactors, as revealed by optimization studies related to the various operating parameters such as molar ratio, catalyst concentration, and reaction temperature, are a reduced reaction temperature (savings in the energy required for heating of the process streams), a lower reaction time (energy savings in reactor), and the requirement of a smaller amount of excess methyl acetate for equivalent levels of equilibrium conversion (considerable energy savings in the separation units). The kinetics of the conversion of triglycerides through interesterification follows a second-order reaction scheme and it was observed that the rate constant increased with an increase in the operating temperature. The properties of biodiesel produced from both methods match the ASTM standards with superior properties for the ultrasound assisted approach. Overall, it can be said that use of ultrasonic irradiations considerably enhances the rates of biodiesel synthesis and would also lead to a substantial energy savings, because of various process improvements such as use of lower temperature and lower excess of reactants, as observed in the present work.