Application of computational fluid dynamics to closed-loop bioreactors: II. Simulation of biological phosphorus removal using computational fluid dynamics.
Based on the International Water Association's (London) Activated Sludge Model No. 2 (ASM2), biochemistry rate expressions for general heterotrophs and phosphorus-accumulating organisms (PAOs) were introduced to a previously developed, three-dimensional computational fluid dynamics (CFD) activated sludge model that characterized the mixing pattern within the outer channel of a full-scale, closed-loop bioreactor. Using acetate as the sole carbon and energy source, CFD simulations for general heterotrophs or PAOs individually agreed well with those of ASM2 for a chemostat with the same operating conditions. Competition between and selection of heterotrophs and PAOs was verified using conventional completely mixed and tanks-in-series models. Then, competition was studied in the CFD model. These results demonstrated that PAOs and heterotrophs can theoretically coexist in a single bioreactor when the oxygen input is appropriate to allow sufficient low-dissolved-oxygen zones to develop.
Littleton
Helen X
HX
Department of Environmental Science, Rutgers University, USA. littletonhx@cdm.com
Daigger
Glen T
GT
Strom
Peter F
PF
D019149:Bioreactors; D003198:Computer Simulation; D010758:Phosphorus / Q000378:metabolism*; D018508:Water Purification
D010758:Phosphorus