Puigagut Jaume, Salvadó Humbert, García Joan
Environmental Engineering Division, Department of Hydraulics, Coastal and Environmental Engineering, Technical University of Catalonia, c. Jordi Girona 1-3, Mòdul D-1, 08034 Barcelona, Spain.
Water Res. 2005 Nov;39(18):4397-404. doi: 10.1016/j.watres.2005.08.008. Epub 2005 Oct 6.
The response of activated sludge microfauna in terms of abundance and diversity has been analysed to evaluate both the toxic effect of ammonia nitrogen and the acclimatisation capacity of these microorganisms to its toxicity. The harmful effect of ammonia nitrogen was studied by means of two toxicological tests. The ammonia concentrations tested were: 9, 20, 30 and 50mg NH4+-N/l in the first toxicological test and 30, 40, 50 and 80 mg NH4+-N/l in the second. The results suggest that ammonia nitrogen causes a clear but reversible toxic effect on microfauna abundance when its concentrations are around three times higher than that which the microfauna is used to. Chilodonella uncinata and Acineria uncinata were the ciliates least affected by the ammonia nitrogen toxicity. Furthermore, the majority of microfauna groups analysed (gymnamoebae and ciliates) showed capability for acclimatisation to ammonia nitrogen in terms of abundance.
