IIT Guwahati develops energy-efficient ammonium removal technique for wastewater

Guwahati, Nov 18:  A research team from the Indian Institute of Technology (IIT) Guwahati, led by Prof. Kannan Pakshirajan of the Department of Bioscience and Bioengineering, has developed a groundbreaking method to remove ammonium from wastewater by using a combination of microalgae and bacteria.

This approach not only offers a sustainable solution but also drastically cuts down on energy consumption compared to traditional wastewater treatment methods.

The research, supported by the Department of Science and Technology—Fund for Improvement of S&T Infrastructure (DST-FIST) programme, has been published in the prestigious Chemical Engineering Journal. The paper was co-authored by Prof Pakshirajan and Prof G Pugazhenthi from the Department of Chemical Engineering, alongside post-doctoral and research scholars Dr Arun Sakthivel, Dr Surjith Ramasamy, and Sumeet Kheria of IIT Guwahati.

Ammonium in wastewater, derived from sources like domestic sewage, industrial waste, agricultural runoff, and landfills, poses serious environmental risks. It can lead to harmful algal blooms, increased water acidity, and oxygen depletion in aquatic ecosystems.

Traditional ammonium removal methods involve oxygenation, which accounts for up to 90 percent of a treatment plant's energy consumption.

Prof. Pakshirajan's team designed a photo-sequencing batch reactor (PSBR), where microalgae produce oxygen during photosynthesis, which is then utilised by nitrifying bacteria to convert ammonium into nitrate, followed by denitrification under anoxic conditions using denitrifying bacteria to form nitrogen as the end product. This eliminates the need for external oxygen aeration, making the process significantly more energy-efficient.

"Our system offers a sustainable solution for treating wastewater while cutting down on energy costs. By harnessing the oxygen naturally produced by microalgae, we can make the process not only more efficient but also highly cost-effective," Prof. Pakshirajan said.

The research combines scientific modelling with real-world data to ensure high ammonium removal rates under various conditions. The system demonstrated an energy savings of up to 91.33 percent in comparison to conventional aeration methods used in wastewater treatment plants, making it an eco-friendly and cost-effective alternative.

Prof. Pakshirajan said that the method marks a significant step forward in sustainable wastewater treatment, offering practical applications for reducing the environmental impact of wastewater across industries.

By-

Staff Reporter