Led by Chair of Process Engineering Vivek Ranade, a research collaboration between CSIR National Chemical Laboratory (NCL), Pune, India and the Bernal Institute, UL has demonstrated a cost-effective green methodology to remove ammoniacal nitrogen from effluent streams. Ammoniacal nitrogen is a measure for the nitrogenous matter as ammonia, a toxic pollutant that can directly poison humans and upset the equilibrium of water ecology systems. It cannot be treated using conventional biological and physico-chemical methods. Industries such as dyes and pigment, nitrogenous fertilizers and specialty chemicals generate wastewaters with high ammoniacal nitrogen (1500–3000 mg/L), which demand specific solutions for wastewater treatment. Similarly, industries such as fisheries generate huge volumes of wastewaters with ammoniacal nitrogen levels of 400–600 mg/L.

The collaborating research groups from UL and NCL used hydrodynamic cavitation for removing toxic pollutants from water. Hydrodynamic cavitation is a process of in situ generation of strong radicals which destroy pollutants. These in-situ generated radicals were harnessed for wastewater treatment. The research group developed novel, vortex based hydrodynamic cavitation devices to optimise utilisation of generated radicals for removing pollutants. In addition to hydrodynamic cavitation, the process was further improved by using simple aeration. This simple trick improved the removal of toxic pollutants like ammoniacal nitrogen by an order of magnitude. The developed vortex-based cavitation devices and aeration may be used alone or in combination with existing established effluent treatment processes to facilitate water recycling and reuse. Further research on scale-up/scale-out (numbering up instead of scaling up) of these cavitation devices is in progress.

The findings of this study are published in ULTRASONICS SONOCHEMISTRY Journal and is available to read here; “Improving efficiency for removal of ammoniacal nitrogen from wastewaters using hydrodynamic cavitation”