Evaluation of two start‐up strategies to obtain nitrogen removal via nitrite and examination of the nitrous oxide emissions for different nitritation levels during the treatment of slaughterhouse wastewater

Abstract

Abstract BACKGROUND This study investigated the use of a novel start‐up strategy to obtain nitrogen removal via nitrite using real‐time aeration control, in a sequencing batch reactor (SBR 1 ), for the treatment of slaughterhouse wastewater. In addition, another SBR (SBR 2 ) was operated with the same objective, but with a start‐up from seed sludge. Furthermore, analysis of the nitrous oxide (N 2 O) production and emission was conducted for different nitritation levels. RESULTS Through the absence of an inoculum in SBR 1 , the nitrifying population could be regulated from the beginning. Beceause of this, nitrite oxidising bacteria could be prevented. This was proved by the nitritation degree (ND) which was already above 80% from day 28, although it took 59 days to achieve sufficient nitrogen removal efficiency (> 80%). In contrast for SBR 2 , it took 90–110 days to achieve full nitritation, however the nitrogen removal efficiency was above 90% at all times. The maximum N 2 O emission resulted to be 0.12% of the nitrogen load. CONCLUSION This study suggested the importance of seeding sludge for the achievement of full nitritation. Moreover, a strong positive relationship between the ND and N 2 O emission was observed. © 2017 Society of Chemical Industry