Effect of salinity on nitrogen removal by simultaneous nitrification and denitrification in a sequencing batch biofilm reactor

Abstract

AbstractA sequencing batch biofilm reactor (SBBR) was operated at different salinities with focus on reactor performance and nitrogen removal by simultaneous nitrification and denitrification (SND). The SBBR contained suspended-growth sludge and biofilm attached to synthetic fibrous carriers. When salinity increased from 1.4 to 4.2 g NaCl/L, it increased the -N and total nitrogen removal efficiencies, the nitrification rate (NR), and denitrification rate (DNR). A slight drop in nitrogen removal, NR, and DNR was observed, when the salinity was increased from 4.2 to 9.8 g NaCl/L. Efficient SND occurred in the reactor and the SND efficiency was above 90.7%. Nitrification was the main contribution of the suspended sludge, while the major role of biofilm was denitrification in the SBBR at the salinity of 9.8 g NaCl/L.