Cristina Moisescu, Ana-Valentina Ardelean, Marinela Cîrnu, Ioan I. Ardelean
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activated sludge, ammonium oxidizing microorganisms, nitrification, recirculating aquaculture system.
In the last decades there are reports concerning attempts to try to increase the amount and activity of a given physiological group of microorganisms from the activated sludge, in order to increase the overall yield of wastewater purification. In this paper we report our original results concerning the selective cultivation of microbial populations in growing media specific for ammonia oxidizing microorganisms (AOM), in order to increase the oxidation of ammonia from artificial wastewaters, model for those related to recirculating aquaculture systems. Different microbial populations were cultivated in batch systems at 20°C, in aerobic conditions, in media with ammonium as sole electron source and carbon dioxide as sole carbon source. The results show that, after appropriate selective cultivation, there is a significant increase in the activity of AOB, in agreement with the increase in cell densities of AOB estimated by MPN technique. The improved populations thus obtained are good candidates for enhancing the removal of ammonia, firstly at laboratory level, from (synthetic) waste waters. However, the stability/resilience of these populations in true life conditions remains to be evaluated.
