Characteristics of a heterotrophic nitrogen removal bacterium and its potential application on treatment of ammonium-rich wastewater

- Nitrogen and organic carbon removal capability of A. faecalis NR were optimized.
- Novel aerobic bioreactor inoculated with A. faecalis NR was successfully applied.
- Fate of nitrogen and organic carbon in the bioreactor was discussed.
- The bioreactor presents possibility to develop innovative treatment technologies.

Nitrogen and organic carbon are major pollutants in wastewater causing environmental problems. Alcaligenes faecalis strain NR, isolated from activated sludge, exhibited the ability to remove ammonium and organic carbon from wastewater simultaneously under sole aerobic conditions in batch culture. Changes in carbon type, C/N ratio, oxygen concentration and inorganic ions significantly affected the treatment efficiency. Furthermore, a continuous bioreactor, solely inoculated with A. faecalis strain NR, was conducted to assess its feasibility for simultaneous nitrogen and organic matter removal in a single aerated reactor. Approximately 66.7-78.3% of NH4+-N and 85.8-92.2% of TOC were removed by using synthetic wastewater with 150-200 mg/L of NH4+-N and 1350-2000 mg/L of TOC. This research would be valuable to develop an innovative treatment method for ammonium-rich wastewater under aerobic conditions.