MODEL-BASED ANALYSIS OF THE EFFECTS OF RECYCLE RATIOS ON THE PERFORMANCE OF AN A²O PROCESS

Authors : Neslihan MANAV DEMİR, Selami DEMİR

Pages : 1741-1751

View : 47 | Download : 5

Publication Date : 2021-10-05

Article Type : Research Paper

Abstract :This study presents findings of a modeling work in which the effects of internal recycle insert ignore into journalissuearticles values(IR); and return activated sludge insert ignore into journalissuearticles values(RAS); ratios on the treatment performance of an A²O process were investigated. Simulations were performed using activated sludge model no.3 extended with biological phosphorus removal processes at an influent wastewater temperature of 20°C. The results showed that not only IR ratio but also RAS ratio affects both nitrogen and phosphorus removal processes. The removal efficiencies for total nitrogen insert ignore into journalissuearticles values(TN); and total phosphorus insert ignore into journalissuearticles values(TP); changed between 71%–83% and 53%–80%, respectively, at different IR and RAS ratios. On the other hand, chemical oxygen demand insert ignore into journalissuearticles values(COD);, total Kjeldahl Nitrogen insert ignore into journalissuearticles values(TKN);, and total suspended solids insert ignore into journalissuearticles values(TSS); removal efficiencies stayed relatively constant at around 90%, 96%, and 93%, respectively, with varying IR and RAS ratios. Results indicated that an optimum set of IR and RAS ratios can be found out by activated sludge modeling. For A²O process, an IR ratio of 2.5 to 3.5 at a RAS ratio of 0.75 to 0.90 offer the best performance in terms of both TN and TP removal efficiencies.
Keywords : A²O process, internal recycle, return activated sludge, activated sludge modeling

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