Klebsiella oxytoca (EN-B2): A novel type of simultaneous nitrification and denitrification strain for excellent total nitrogen removal during multiple nitrogen pollution wastewater treatment

The poor total nitrogen (TN) removal rate achieved using microorganisms to treat wastewater polluted with multiple types of nitrogen was improved using a novel simultaneous nitrification and denitrification strain (Klebsiella oxytoca EN-B2). Strain EN-B2 rapidly eliminated ammonium, nitrate, and nitrite, giving maximum elimination rates of 4.58, 7.46, and 7.83 mg/(L h), respectively, equivalent to TN elimination rates of 4.35, 6.92, and 7.11 mg/(L h), respectively. The simultaneous nitrification and denitrification system gave ammonium and nitrite elimination rates of 7.14 and 9.17 mg/(L h), respectively, and a TN elimination rate >= 9.0 mg/(L h). Nitrogen balance calculations indicated that 51.22 %, 31.62 % and 46.82 % of TN in systems containing only ammonium, nitrite, and nitrate, respectively, were lost as nitrogenous gases. The ammonia monooxygenase, hydroxylamine oxidoreductase, nitrate reductase and nitrite reductase enzyme activities were determined. The results indicated that strain EN-B2 can be used to treat wastewater polluted with multiple types of nitrogen.

Automated summary

The use of a novel strain (Klebsiella oxytoca EN-B2) improved the poor total nitrogen (TN) removal rate achieved when treating wastewater polluted with multiple types of nitrogen using microorganisms. Strain EN-B2 showed rapid elimination of ammonium, nitrate, and nitrite, with maximum elimination rates equivalent to TN elimination rates. The simultaneous nitrification and denitrification system using strain EN-B2 achieved high elimination rates for ammonium, nitrite, and TN. Nitrogen balance calculations revealed significant losses of TN as nitrogenous gases in systems containing only ammonium, nitrite, and nitrate. The enzyme activities of ammonia monooxygenase, hydroxylamine oxidoreductase, nitrate reductase, and nitrite reductase were determined, indicating the suitability of strain EN-B2 for treating wastewater polluted with multiple types of nitrogen.