Development of of simultaneous partial nitrification, anammox and denitrification (SNAD) in a non-aerated SBR

The objective of this work was to develop simultaneous partial nitrification, anammox and denitrification (SNAD) process in a twenty liter non-aerated sequencing batch reactor (SBR). Flocculent type activated sludge sourced from a tannery common effluent treatment plant was used as seed biomass. The SBR was operated for 161 days in 23 cycles with initial feed concentrations of NH4-N and COD as 250 t 14.9 mg l(-1) and 250 +/- 4.6 mg l(-1), respectively. The process was developed in a non-mixing condition in a dark room with no temperature control, but the temperature in SBR varied between 30 degrees C and 36 degrees C. The average HRT was 10.5 d with SBR cycle time of 7 d. The last three cycles gave the best average removals of NH4-N (94%), COD (92%) and TN (82%). The conversion ratio Y(NO2-N+ NO3-N)/(NH4-N) during the last 10 cycles remained below Oil. confirming a stable SNAD process. Maximum specific substrate (NH4-N, COD and TN) utilization rates of SNAD biomass were determined as 185 mg NH4-N g(-1) MLVSS d(-1), 153 mg COD g(-1) MLVSS d(-1) and 172 mg N g(-1) MLVSS d(-1). These results contribute towards the application of SNAD process in shallow anoxic ponds/tanks/ditches in the absence of sunlight. (C) 2016 Elsevier Ltd. All rights reserved.