In 2003, Singapore’s national water agency launched an unprecedented program to provide more than 50% of their nation’s water supply by recycling wastewater. The program had been planned for decades to ensure the island nation never ran out of clean water. But is it really safe to reuse anything we flush down the toilet? Francis de los Reyes explains the science of wastewater treatment. Lesson by Francis de los Reyes, directed by JodyPrody, The Animation Workshop.