Low-Carbon Nitrogen Removal from Actual Landfill Leachate Achieved through Heterotrophic-Autotrophic Coupled Biological Treatment System

Strategic Insights -

A new study from Shandong University has revealed a novel biological treatment system that effectively removes nitrogen from actual landfill leachate while minimizing carbon emissions. The heterotrophic-autotrophic (H-A) coupled system, composed of an anaerobic-anoxic-oxic (A2O) process, an anaerobic membrane bioreactor (AnMBR), and a sulfur-driven autotrophic denitrification filter (SADF), demonstrated high total nitrogen (TN) and ammonia nitrogen (NH4+-N) removal efficiencies of 97.6% and 99.6%, respectively, with carbon emissions as low as 20.97 kg CO2-eq/m3.

Key Takeaways:

  • The H-A coupled system achieved high nitrogen removal efficiencies through the synergistic action of heterotrophic and autotrophic microorganisms.
  • The system's heterotrophic units efficiently depleted biodegradable dissolved organic matter (DOM), facilitating heterotrophic denitrification driven by Truepera and Caldilineaceae.
  • The autotrophic unit utilized sulfur-oxidizing bacteria (SOB) such as Thiobacillus and Castellaniella to continuously reduce nitrate (NO3--N) to nitrogen gas (N2).
  • The system maintained the stability of influent water quality for the autotrophic unit and effectively avoided carbon emissions associated with external carbon supplementation.
  • The study provided a basis for optimizing the combinations between autotrophic and heterotrophic processes in actual landfill leachate treatment.

Statistics:

  • Total nitrogen (TN) removal efficiency: 97.6%
  • Ammonia nitrogen (NH4+-N) removal efficiency: 99.6%
  • Carbon emissions: 20.97 kg CO2-eq/m3
  • Sulfur-oxidizing bacteria (SOB) utilized: Thiobacillus (21.6%) and Castellaniella (21.2%)

Sources:

  • Low-carbon Nitrogen Removal From Actual Landfill Leachate By Heterotrophic-autotrophic Coupled Biological Treatment System and Its Functional Mechanisms. Journal of Cleaner Production, 2025;525. (Elsevier Sci Ltd, 125 London Wall, London, England - www.elsevier.com, Journal of Cleaner Production - www.journals.elsevier.com/journal-of-cleaner-production/)
  • Zhen Hu, Shandong University, School of Environmental Science and Engineering, Shandong Key Lab Environm Proc & Hlth, Qingdao 266237, People's Republic of China.