EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

The fate of nitrification and urease inhibitors in simulated bank filtration 

Muhammad Zeeshan1,2, Marco Scheurer3,4, Christina Förster5, Christine Kuebeck6, Aki Sebastian Ruhl1,2, and Sondra Klitzke7
Muhammad Zeeshan et al.
  • 1German Environment Agency, Section II 3.3, Schichauweg 58, 12307, Berlin, Germany
  • 2Technische Universität Berlin, Water Treatment, KF4, Str. des 17. Juni 135, 10623, Berlin, Germany
  • 3TZW: DVGW-Technologiezentrum Wasser, Karlsruher Str. 84, 76139 Karlsruhe, Germany
  • 4Landesanstalt für Umwelt Baden-Württemberg, Griesbachstr. 1-3, 76185 Karlsruhe
  • 5German Environment Agency, Section II 3.5, Heinrich-Heine-Straße 12, 08645 Bad Elster, Germany
  • 6IWW Water Centre, Water Resources Management, Justus-von-Liebig-Str. 10, 64584 Biebesheim am Rhein, Germany
  • 7German Environment Agency, Section II 3.1, Schichauweg 58, 12307, Berlin, Germany

Nitrification and urease inhibitors (NUI) are used in conjunction with nitrogen (N) fertilizers on agricultural soils to improve the efficiency of N fertilizers and reduce the emission of greenhouse gases. After application, NUI might transfer to aquatic environments through leaching or surface runoff. Nowadays, NUI such as 1,2,4-triazole, 3,4-dimethylpyrazole (3,4-DMPP) and dicyandiamide (DCD) are frequently found in surface waters with concentrations in the magnitude of µg/L. The fate of NUI in bank filtration (BF) is currently poorly known. BF is a sustainable water treatment system providing high quality water by efficiently removing numerous organic micropollutants from the source water. Herein, sorption and degradation of NUI in simulated BF under near-natural conditions was investigated. Besides, the effect of NUI on the microbial biomass of slowly growing microorganisms and the role of microbial biomass on NUI removal was investigated. Duplicate sand columns (length 1.7 m), fed with surface water were spiked with a pulse consisting of four nitrification (1,2,4-triazole, DCD, 3,4-DMPP and 3-methylpyrazole) and two urease inhibitors (n-butyl-thiophosphoric acid triamide and n-(2-nitrophenyl) phosphoric triamide). The average spiking concentration of each NUI was 5 µg/L. The flow velocity was adjusted to 0.2 m/d. Breakthrough curves of tracer (sodium chloride) and the NUI appeared at same time; therefore, sorption may be ruled out. Additionally, experimental and modeled breakthrough curves of NUI suggested no retardation for any of the inhibitors. Therefore, biodegradation was identified as the main elimination pathway for all substances and was highest in zones of high microbial biomass. N-butyl-thiophosphoric acid triamide was completely removed within a hydraulic retention time (HRT) of 24 hours and proved to be a highly degradable substance. Nitrification inhibitors showed 50% mass recovery (except for 3,4-DMPP) after an HRT of 4 days. A slight effect of NUI on microbial biomass was observed. This study highlights that hydraulic retention time and microbial biomass are key indicators for the degradation of NUI.

How to cite: Zeeshan, M., Scheurer, M., Förster, C., Kuebeck, C., Ruhl, A. S., and Klitzke, S.: The fate of nitrification and urease inhibitors in simulated bank filtration , EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-9942,, 2023.