Paper Title
High Nitrite Concentration Inhibits Nitrite-Adapted Granular Anammox Biomass Less Compared to Biofilm

Abstract
Anaerobic ammonium oxidation (anammox) processis developed for nitrogen removal from nutrient- rich wastewater treatment. It has been testedintensively, but the process lacks optimized values of nitrite inhibition, whichneeds to be defined. In following research, spikingof nitrite (fastly inclining NO2−- content in the biofilm (MBBR) or sequencing reactor (SBR)above 20 mg NO2−-NL−1) wasresearched on anammox bacteria.Research was done on three setups: MBBR, SBR and onupflow anaerobic sludge blanket (UASB). Inhibitingvalues and contentsinhibiting 50% of anammox activity (IC50) was defined in the batch assays. Spiked- added nitrite content on anammox biomass was less affected by nitrite inhibition. The results of border values causinginhibitionand IC50 concentrations beingnot different for non-nitrite spiked biomass (81 and 98 mg NO2−-NL−1, respectively, for SBR. IC50 was importantly differentin UASB nitrite spiked and for non-nitrite spiked biomass(83 and 240 mg NO2−-NL−1, respectively). A very high total nitrogen removal beingdeterminedforpreviousborder values suggestedastrong limitation effect byNO2− on anammox biomassas earlier depicted. The quantitative polymerase chain reaction (qPCR)testselucidated similar values of copies of anammox 16S rRNA in SBR, MBBR and UASB systems, the least were represented within SBR and the most in the MBBR (3.98 × 108 and 1.04 × 109 copies g−1 TSS, respectively). Keywords - Anammox, Autotrophic Nitrogen Removal, Nitrite Inhibition, Suspended Sludge