Pilot 10 – Nitrate removal using IEMB reactor

Location: Chennai (Tamil Nadu)
Pilot Leaders: BGU/IITM
Pilot Status: One pilot module with a capacity 2 m3/day was installed at IIT Madras campus sewage treatment plant (STP) in January 2022 and been monitored since the installation. Automation of the first pilot module was finished recently and now it is running completely automated. Second pilot module will be installed in a municipal STP at Nesepakkam, Chennai by 15th August 2022.

Water challenge in this location: Tamil Nadu is a drought prone area where it is difficult for residents to get sufficient drinking water. Secondary wastewater is considered today a promising source for potable applications, but nevertheless there is a need for additional treatment steps to overcome the social stigma of using this source for potable use. For this purpose, it is stored in water bodies, followed by treating to meet the stringent drinking water standards During the surface water recharging, nitrate removal to a sufficiently low level is required to avoid the eutrophication and further toxification of the water.

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;
  • 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;
  • More energy efficiency compared to other existing methods as no external energy is required for the separation process.

Potential for India: Greatly reduce health risks of using recycled water for drinking – many supplies are presently compromised, and this would help to provide safe drinking from these supplies

Scope of replication/upscaling across India: Treated wastewater has a great potential for reuse as a drinking water source. Currently, membrane processes such as reverse osmosis (RO) are used for treating wastewater for drinking purposes which results in a lot of reject and high maintenance costs. Hence, such a system can be used as an add on units to any existing wastewater treatment plant with excess nitrate and nitrite levels.

Main outcomes: Increase in the reuse potential of treated wastewater, cope up with increasing drinking water demand and solution to prevent to eutrophication of the water bodies.

Public deliverables: Pilot scale system, performance report and standard operating procedure (SOP).

Other public materials: Technological details.