Main-stream Partial Nitritation/Anammox process coupled to a membrane bioreactor. Start-Up and Operation
In this project, a two-stage (Partial Nitritation-Anammox; PN/A) deammonification pilot plant was operated with municipal wastewater to investigate the long-term stability of the PN/A process at mainstream conditions and the impact of low temperature on the anammox process. The pilot plant with suspended biomass was operated at the WWTP in Simmern, Germany, for 214 days with the start-up in winter, and 80 days with a start-up in autumn. The piilot plant layout consisted of an influent finescreen, followed by a PN reactor, Anammox reactor, membrane bioreactor (MBR) (with ultrafiltration (UF) membranes) and a sieve for the waste sludge to retrieve anammox bacteria and return it to the system. The dissolved oxygen (DO) concentration was used to control the aeration in PN reactor.
During the experimental period, the pilot plant showed a stable COD removal efficiency between 90 and 95%. The nitrogen removal of the pilot plant was unstable due to issues with influent wastewater and in air supply caused by fine sieve, influent pump and blower failures.