Aeration control for simultaneous nitrification-denitrification in a biological aerated filter using internal model approach

Abstract

Experience has shown that simultaneous nitrification/denitrification in a biological aerated filter is possible. However these systems react very sensitively to the aeration control strategies applied. Poorly adapted control strategies induce a strong decrease in treatment efficiency. A new control strategy for simultaneous N/DN is developed. The strategy proposed makes use of ammonia measurements and the inlet and outlet: a Feedback/Feedforward block. Passing by a calculation of the load to be eliminated, an estimation of the air flow velocity to be applied is carried out dynamically. A retroactive loop corrects this prediction in order to reach exactly the desired set point. This control approach has been implemented and tested at pilot plant scale for a period of 18 months. The pilot plant consists of two coupled BAF cells, reflecting closely industrial scale situations. Comparative studies reveal clearly the improved performance of the developed FF/FB control strategy compared to classical controllers. The benefits include 5% increase in nitrogen removal performance and a reduction of 15 to 20% in air requirement, offering a rapid return of investment costs.

Effects of reduced aeration in a biological aerated filter

“…Efficiency was higher for higher organic influent loading. Lemoine et al (2006) did an extensive study to find the amount of aeration for a simultaneous nitrification and denitrification system by using an internal model approach.…”

Simultaneous nutrients and carbon removal from low-strength domestic wastewater with an immobilised-microorganism biological aerated filter

“…It is better than the activated sludge systems in terms of system stability and compactness, because high concentration of active biomass can be maintained and suspended solids in the influent can be captured physically. Moreover, by reason of the gradient of dissolved oxygen (DO) from the interior to the exterior of the carrier, it is effective in removing carbon and nitrogen concurrently (Lemoine et al 2006;Rogalla et al 2006). In particular, phosphorus removal can be achieved in BAF systems operated under alternated anaerobic/aerobic conditions (Shanableh et al 1997;Zheng & Long, 2008).…”

Experimental Study on Simultaneous Nitrification and Denitrification in Municipal Wastewater

“…Many techniques and methods have been developed to remove nitrogen efficiently and economically [2][3][4][5][6]. According to the traditional denitrification theory, nitrification and denitrification can not be in the same process at the same time, however, according to the recent abroad papers, the phenomena of simultaneous nitrification and denitrification, especially the anti-aerobic denitrification phenomenon existed in various biological treatment systems [7][8][9][10]. The phenomena of simultaneous nitrification and the denitrification effect in SBR process was studied in this paper.…”