Results show that the new plant design performed
significantly better in open-loop compared to the old open
loop. The Effluent Quality Index (EQI) decreased by 44%,
mainly because of better TN removal. Effluent SNH (SNH,e)
violations, being the percentage of time SNH,e exceeds
4gNm23, are reduced by 85% and the average effluent SNH
is reduced as well. Moreover, this improvement does not
deteriorate the level of SNO,e as was observed to be the
trade-off (either sacrifice on SNH,e or on SNO,e) in Jeppsson
et al. (2007). Furthermore, the increased anoxic volume