A novel process for low-sulfur biodiesel production from scum waste

•A new process was developed to convert scum to low sulfur biodiesel.•Solvent extraction combined with acid washing was used to clean the scum oil.•Activated carbon was integrated with reflux distillation to reduce sulfur content.•70% filtered and dried scum was converted to biodiesel with sulfur content ⩽15ppm.•Biodiesel from new process showed better properties than that from other processes.