Master’s thesis

Monitoring of microbial activities in total anaerobic nitrogen removal processes


The actual nitrogen removal step in conventional and future nitrogen removal systems at wastewater treatment plants (WWTPs) are all anaerobic. At conventional municipal WWTPs heterotrophic denitrifiers convert nitrite into dinitrogen gas. The autotrophic anaerobic ammonium oxidising (anammox) bacteria has been implemented for nitrogen removal in warm and highly concentrated sludge liquors and industrial wastewaters at nearly 100 full-scale applications worldwide. The next challenge is to implement fully autotrophic nitrogen removal (i.e. nitritation-anammox) in the mainstream of municipal wastewater treatment plants.

At Sjölunda WWTP in Malmö, most of the denitrification is performed in moving-bed biofilm reactors (MBBRs) as a post-treatment step with methanol as a carbon source. In 2016, a pilot project called Nanammox (acronym for Nitritation-anammox) will be operated at Sjölunda WWTP for investigating the possibility to implement the nitritation-anammox process in a two-stage MBBR process.

Stefansdottir (2014) developed a manometric method for ex-situ batch test measurements of activities of denitrifiers and anammox bacteria. This method has not been used to study the variability of denitrifying capacities in different reactors of the full-scale post-denitrifying MBBR at Sjölunda. Also, it is interesting to follow the anammox activity in the anammox reactor of the Nanammox project.


The main objective of the master´s thesis is to monitor possible variations in activity of anaerobic nitrogen transforming bacteria in the full-scale post-denitrifying MBBRs and in the Nanammox pilot and couple these variations with the operational results. This evaluation is aimed to be used for identify good operational strategies.


The student will be involved in the project group of the Nanammox project. Simple ex-situ manometric laboratory batch tests will be used to specify denitrifying and anammox activities. All laboratory work will be performed at Sjölunda WWTP.


David Gustavsson, research leader at VA SYD/Sweden Water Research


Spring 2016


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