Performances of Anammox-EGSB bioreactors started up with three different seeding sludges

Abstract:

In order to select better seeding sludge and promote start-up of Anammox reactors, we studied the start-up performances of three Anammox-EGSB bioreactors inoculated with anaerobic methanogenic sludge (AMS) (R1), Fresh Anammox sludge (FAS) (R2) and stored Anammox sludge (SAS) (R3), respectively. Results showed that these three seeding sludges could start up Anammox-EGSB bioreactors successfully, but the start-up progresses showed different characteristics. The start-up course of R1 could be divided into three phases including autolysis phase (15 d), lag phase (54 d) and activity elevation phase (40 d). However, the start-up courses of R2 and R3 only included lag phase (2 d and 12 d, respectively) and activity elevation phase (15 d and 57 d, respectively). Besides, the performance of R3 was better than that of R1, but worse than that of R2. Furthermore, bathing the Anammox sludge in the effluent of bioreactors was a convenient and effective way to keep the activity of the Anammox sludge. The ammonia removal efficiency, percentage of denitrification and the stoichiometric ratios of NH4+-Nr/NO2?-Nr and NO3?-Np/NH4+-Nr could serve as indicators to monitor the start-up of Anammox bioreactors.