The Environmental Management and Policy Research Institute (EMPRI) in Bengaluru has unveiled a new gravity-based sewage treatment plant (STP) on January 6, 2025. The STP operates using gravity rather than electricity and can function without maintenance for two years. The facility is capable of treating up to 10,000 litres of wastewater per day, employing a four-stage operating process that harnesses gravitational force to convert wastewater into secondary treated water.
The sludge is extracted during the first two stages through sedimentation filters, after which the water is channelled through a bacterial filter medium in the third stage. In the fourth stage, the treated water flows through a wetland system where vascular plants and algal colonies remove excess nutrients. Maintenance of the STP largely involves desludging, which is required once every two years.