which might be of mayor impact on the stripping performance. It is well known that the concurrent CO2 removal influences the carbonate buffer system (alkalinity) in the course of stripping and leads to improved ammonia stripping due to the pH raise (Budzianowski and Koziol, 2005 and Ni, 1999). Change of alkalinity as a major parameter of influence was monitored in many studies on ammonia stripping (Bonmatí and Flotats, 2003, De la Rubia et al., 2010 and Wäger et al., 2009). It can be generally perceived that higher CO2 concentration provide less efficient CO2 stripping. However, no reports quantifying the effect of CO2 rich strip gases on the course of alkalinity during ammonia stripping are found.