Process for Separating and Recovering Ammonium (NH₄⁺) from Wastewater Using a Centrifugal Rotating Packed Bed Device

Utility Solution Patent No. 3400: “Process for Separating and Recovering Ammonium (NH4⁺) from Wastewater Using a Centrifugal Rotating Packed Bed Device”
Authors: Dr. Do Van Manh, Assoc. Prof. Nguyen Viet Thoan
Institution: Institute of Energy and Technology for Energy and Environment (formerly the Institute of Environmental Technology)

Assoc. Prof. Dr. Do Van Manh, Institute of Energy and Technology for Energy and Environment

The patented process enables the separation and recovery of ammonium (NH4⁺) from wastewater under high-pH conditions, utilizing a centrifugal rotating packed bed device combined with air stripping. By adjusting the wastewater pH to an alkaline level and using the rotating packed bed with a suitable air-to-water flow ratio, the process effectively removes ammonium from wastewater. This not only reduces total Kjeldahl nitrogen (TKN) but also recovers nitrogen from ammonium for agricultural use, thereby generating both environmental and economic benefits..

In Vietnam, over the past 15 years, research and practical applications for ammonium removal have mainly focused on ammonia stripping towers used in leachate treatment. However, these towers have low treatment efficiency and require long processing times. Therefore, developing a high-efficiency, rapid, and energy-saving ammonium removal solution with compact equipment and minimal installation space has become an urgent need.

The Utility Solution Patent No. 3400 was granted by the Intellectual Property Office of Vietnam under Decision No. 92027/QĐ-SHTT dated November 1, 2023.

The patented process for separating and recovering ammonium (NH4⁺) from wastewater using a centrifugal rotating packed bed device includes the following steps:

1. pH Adjustment: Increase the wastewater pH to 10.5.
2. Ammonia Separation: Remove ammonia (NH3) from the high-pH wastewater using the centrifugal rotating packed bed device. The device structure and operating mode promote a phase transfer process, where NH3 transitions from liquid to gas.
   • The wastewater flows through fine droplets within the packed material.
   • Counter-current air flow carries the released NH3 gas toward the central outlet of the device.
   • Treated water, now free from ammonia, exits through the discharge pipe.
3. Neutralization: Lower the pH of the treated water to 7.5 before discharge.

The process offers significant advantages and broad application potential. It achieves a high ammonium removal efficiency within an extremely short treatment time, reducing both operational costs and energy consumption. The compact design of the centrifugal rotating packed bed device minimizes equipment size and installation space requirements, making it suitable for facilities with limited area. In addition, the process allows for the recovery of nitrogen from wastewater in the form of ammonia, which can be reused in agriculture, thereby transforming waste into a valuable resource. Beyond its technical efficiency, the solution provides a novel and sustainable approach to nitrogen management in wastewater, contributing to pollution reduction, promoting the circular economy, and supporting long-term sustainable development in environmental engineering and wastewater treatment.