Nitrifyers in constructed wetlands
treating landfill leachates
Carina Sundberg
Linköping University Medical Dissertations No. 1067
Linköping 2008
Landfill leachate will be produced many years after a land-fill is closed. Hence, treatment by “natural methods”, as e.g. constructed wetlands, with low management require-ments is attractive. Constructed wetlands usually provide both shallow and deep areas with aerobic and anaerobic zones, which is perfect for nitrification followed by denitri-fication of the ammonium-rich leachates. Full-scale treat-ment systems will be influenced by climatic variables that affect the microbial community. Also, the operational stra-tegy can have a considerable impact on both activity and composition of the microorganisms. This study investiga-ted the microbial community involved in nitrogen removal in treatment wetlands with a focus on ammonia oxidising bacteria. Variations in full-scale systems were investigated, using short-term incubation and molecular methods. A sta-ble community composition and potential ammonia oxida-tion were detected in a system with a year-round operaoxida-tion. All systems supported diverse ammonia oxidising bacterial community, represented by several Nitrosomonasand Ni-trosospirapopulations. The number of different populations detected in these wetlands was much higher than reported in municipal wastewater treatment plants, and differed from those in a parallel area treating municipal wastewater.
Carina Sundberg received her graduate education at the
Department of Medical Microbiology, IKE, LinköpingUni-versity. She received her undergraduate Master of Sci-ence in Biology at LinköpingUniversity.
