Startup and Pilot Testing of MBBR and IFAS Partial Denitrification/Anammox Processes

This study was conducted to investigate the startup requirements of a partial denitrification/anammox (PdNA) moving bed biofilm reactor (MBBR) and the carbon demand and nitrogen removal capabilities of a two-zone MBBR process and a PdNA integrated fixedfilm activated sludge (IFAS) process. The MBBR process consisted of a PdNA zone followed by an anammox zone. During the startup experiment, anammox activity was detected less than 2 months after startup in MBBRs containing either preliminary biofilm or virgin carriers, demonstrating that anammox could be grown in a mainstream polishing PdNA MBBR without seed, and with low effluent ammonia and nitrite concentrations. Operation of the PdNA MBBR and IFAS processes showed that both a mainstream polishing PdNA MBBR and PdNA IFAS reactor can produce low effluent TIN concentrations with relatively low carbon requirements compared to the conventional nitrification/denitrification nitrogen removal process, even with relatively low and unstable partial denitrification (PdN) efficiencies in both.