Water challenge in this location: The SBR plant at IIT Madras features a tertiary treatment system consisting of ultra-filtration and ozonation. Though anoxic system is provided in the SBR, the treated water is still having significant levels of nitrate (10-25 ppm) and nitrite (7 – 9 ppm). As a result of residual nutrients, the storage ponds are having significant amount of eutrophication. This also limits the reuse potential of the treated water. Providing a treatment system to reduce the residual nutrients will increase the treated water reusability significantly.
Benefits of the technology: Providing a treatment system that reduces the residual nitrogen-based nutrients significantly increases usability of the treated secondary and tertiary effluents. The main advantages of the technology include:
- Bioreactor kept separate from the water treated – so no need to remove back-contamination of bacteria or organic load;
- Simple to operate – just two process flow streams and simple controls for pH; and
- It is flexible in that multiple modules in parallel allow increase in capacity and multiple modules in series allows to reach whatever extent of nitrate/nitrite removal that is required.
Potential for India: Greatly reduce health risks of using recycled water for irrigation and drinking – many supplies are presently compromised, and this would help to provide safe drinking and irrigation water from these supplies.
Scope of replication/upscaling across India: Nutrient pollution is a major problem in India. Most of the existing sewage treatment plants do not have the facility to remove nutrients. Hence, such a system can be used as add on units to any existing wastewater treatment plant with excess nitrate and nitrite levels. Hence there is significant potential for replication and upscaling across India.