The influence of the inoculum and the use of zeolite as a support in the start-up of an anammox sequential batch reactor (SBR)

The main disadvantage of the anammox process is the slow growth of biomass, with the subsequent slow start up the reactor. Due to the fact that there are no anammox bacteria available in Chile, the first objective of this study was to determine from which inocula, anammox bacteria could be obtained. Additionally, the inclusion of a microbial support, such as zeolites, is studied to determine whether they help in the start-up and operation of the anammox process. The results showed that four inocula were studied, two of them from aerobic plants and the other two from anaerobic plants, only the inocula from an aerobic plant (where aerobic degradation of organic material occurs and nitrification) contained anammox bacteria. This inoculum achieved 68.4% removal of ammonia nitrogen (fed sub-stoichiometric amount) and 96.3% for nitrite, working with NLR of 0.1 kgN/m3/d. The maximum SAA obtained was 0.30 gN/gVSS/d. Furthermore, there not is evidence of the influence of the zeolite in the anammox bacteria growth.