How Wastewater Is Made to Be Safely Drinkable

In an transforming TED-Ed lesson written by Francis de los Reyes and animated by JodyPrody, narrator Addison Anderson explains how wastewater can be made safely drinkable through two different, yet equally thorough, treatment processes. One of these processes was adopted by Singapore in 2003 and increased their water stores by over 50%.

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.

Now researchers are looking at ways to bring this process to areas around the world in need of potable water through the use of direct potable reuse.

One common process includes micro-filtration, where membranes with pores one millionth of a meter across filter out small particles and larger microorganisms. Next, the water passes through an even finer reverse osmosis membrane, … After this stage, UV lamps are plunged into the water, emitting radiation that permanently damages the genetic material of any lingering life forms….This approach is called direct potable reuse….Researchers are investigating smaller scale technologies to recycle sewage into potable water on site.

Most systems use indirect potable reuse, which requires connection to a sewage system, meaning that it may not address those who need potable water the most.

Most places opt for indirect potable reuse, where the treated wastewater is discharged to an environmental buffer, such as a reservoir, lake, wetland, or groundwater aquifer. … Then, the water can be extracted and enter the drinking water pipeline…. But this system is only feasible in places with centralized sewer systems and infrastructure for pumping water into people’s homes. This means it can’t help communities dealing with the most serious sanitation issues, where access to clean water is a daily struggle. 

How Wastewater Becomes Drinkable