An activated sludge aeration control concept was developed utilizing off‐gas nitrous oxide concentrations as a surrogate for autotrophic nitrifying bacterial inhibition and aeration air as a master control variable. The control concept was evaluated using a simulated pilot scale bioreactor (mathematically calibrated liquid phase process model and a model to link off‐gas nitrous oxide generation to liquid phase conditions) as a data generator. When applied to the simulated system, the process controller was successful at maintaining the process at the desired operating setpoint and promoting stable operation by minimizing periods of significant inhibition. Furthermore, it provided a more efficient use of the air supplied to the bioreactor during periods of varying feed loading by matching the air supply to the metabolic demands, substantially reducing periods of over and under‐aeration. The findings of this research demonstrate the potential for off‐gas nitrous oxide monitoring as a completely non‐invasive alternative to liquid phase monitoring used in conventional dissolved oxygen control. Investigations are currently underway at the laboratory scale to evaluate the benefits and limitations associated with this control concept, with particular emphasis on implementation issues and the quantification of potential aeration and cost savings.

Item Type:	Refereed Article
Keywords:	wastewater treatment, nitrification, process control
Research Division:	Engineering
Research Group:	Chemical engineering
Research Field:	Wastewater treatment processes
Objective Division:	Commercial Services and Tourism
Objective Group:	Water and waste services
Objective Field:	Water recycling services (incl. sewage and greywater)
UTAS Author:	Sivret, E (Dr Eric Sivret)
ID Code:	140883
Year Published:	2008
Web of Science® Times Cited:	12
Deposited By:	Engineering
Deposited On:	2020-09-14
Last Modified:	2020-10-21
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