In this study, the electrostatic separation process was employed to recover biowaste from waste mixtures. The recovered biowaste is a potential source of alternative renewable energy (e.g. biomass energy). Taguchi’s methodology of experimental design was used for a robust design of both system and random factors. Robust design attempts to analyze the influence of respective factors towards the separation process and, meanwhile, limits the negative impact of the hard-to-control random factors. The effects of four factors, namely voltage level, rotation speed, water content, and particle size diameter were determined. It was noticeable that voltage level has a maximum effect (39.44%) on effective recovery of biowaste, followed by size diameter, water content, and rotation speed within design range. On the other hand, the minimal middling product was mostly influenced by the voltage level (79.78%). The water content has a negligible effect (0.78 %) if compared to rotation speed and size diameter. This paper concluded the appropriate operational range to have less error from the variations of noise.