Skip to main content
Article thumbnail
Location of Repository

Feasibility of biological aerated filters (BAFs) for treating landfill leachate

By Tom Stephenson, Simon J. T. Pollard and Elise Cartmell


Ammonia can be removed from landfill leachate through aerobic biological processes. The biological aerated filter (BAF) combines biological treatment and subsequent biomass separation in one reactor providing a small footprint alternative to conventional systems. Leachate from an operational landfill was found to be aerobically treatable using the OECD recommended Modified Zahn- Wellens test. This leachate was used as feed to a pilot-scale BAF at influent COD and ammoniacal-nitrogen concentrations of 765 mg/l and 568 mg/ l respectively. During an initial period of stable operation without pH control, 33 % of influent ammonia was removed. The reactor pH was 9.2 with little conversion to total oxidized nitrogen (<45 mg/l). Therefore this removal was accounted for primarily by air stripping. In a second period of stable operation, the reactor pH was reduced to pH 7.2 by addition of hydrochloric acid. Ammonia removal was increased to 97 % with a concomitant increase in effluent nitrite concentration to an average of 524 mg/l. Biological aerated filters can therefore be used to nitrify landfill leachates

Year: 2004
OAI identifier:
Provided by: Cranfield CERES

Suggested articles


  1. (1998). A comparison of floating and sunken media biological aerated filters for nitrification. doi
  2. (1999). A review of biological aerated filters for wastewater treatment. doi
  3. (1996). Aeration investigations of biological aerated filters using off-gas analysis. doi
  4. (1992). Anaerobic-aerobic treatment of high-strength ammonium waste-water – nitrogen removal via nitrite. Water Sci.
  5. (1999). BAF media: ideal properties and their measurement. doi
  6. (1998). Biological nitrogen removal from municipal landfill leachate in a pilot scale suspended carrier biofilm process. doi
  7. (1986). Biological treatment of a landfill leachate in a sequencing batch reactor. doi
  8. (1976). Inhibition of nitrification by ammonia and nitrous acid.
  9. (1992). Leachate collection, treatment and disposal. doi
  10. (1977). Nitrification and nitrogen removal. doi
  11. (1988). of the Environment doi
  12. of the Environment (1981a) Ammonia in waters. Methods for the Examination of Waters and Associated Materials.
  13. of the Environment (1981b) Oxidised nitrogen in waters. Methods for the Examination of Waters and Associated Materials.
  14. of the Environment (1981c) Determination of alkalinity and acidity of waters. Methods for the Examination of Waters and Associated Materials.
  15. of the Environment (1981d) Chloride in waters and sewage effluents. Methods for the Examination of Waters and Associated Materials.
  16. (1981). Organisation for Economic Co-operation and Development doi
  17. (1998). Performance of an on-site UASB reactor treating leachate at low temperature. doi
  18. (1997). Phosphorus removal by chemical precipitation in a biological aerated filter. doi
  19. (1972). Removal of ammonia by air stripping.
  20. (1989). Stability of nitrite build-up in an activated sludge system. doi
  21. (2001). The effects of media size on the performance of biological aerated filters. doi
  22. (1991). Treatment of landfill leachate with rotating biological contactors: bench-scale experiments.

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.