AskNature

The Challenge

Indoor plumbing improves sanitation in human settlements, but produces vast amounts of harmful wastewater. This is especially true in densely populated areas such as Bengaluru, where most sewage has been returned untreated into the environment.

Conventional sewage treatment plants use oxygen-breathing bacteria and chemicals to decompose and detoxify this water. The process uses energy-intensive motors and fans to blow air over open tanks, is expensive to run, and poses noise, odor, and safety problems. Can sewage be treated in a more safe, eco-friendly, and sustainable way––especially in remote or less-developed areas?

Innovation Details

ECOSTP has invented an underground sewage treatment system that requires no power and has no moving parts. Water containing human waste flows via gravity through a series of chambers. Heavier solid materials sink to the bottom of initial chambers, while lighter, more diffuse organic matter and pathogens move progressively through additional  chambers, where they are decomposed by anaerobic bacteria, which don’t need oxygen. A final series of chambers is designed like wetlands, with the increasingly clean water flowing among plants whose roots capture a range of pollutants. Emerging at the end is clear, clean water that, with subsequent processing, can be used for agriculture, bathing, and even drinking.