A new tracer gas method to measure oxygen transfer and enhancement factor on RBC

Dimensional analysis for modeling oxygen transfer in rotating biological contactor

“…Attempt was also made to predict K L a for the three reactors used in this study using models available in the literature. Kim and Molof model significantly overestimated the experimental K L a values obtained in the reactors utilized by Bintanja et al (1975), Zeevalkink et al (1979), Paolini (1986), Boumansour and Vasel (1998), Kubsad et al (2004) and for the reactors utilized in this study. Kim and Molof model could fit the experimental K L a observed for their reactor while none of the other models could provide a good fit to the experimental values reported for the reactor used by Kim and Molof (1982).…”

“…The model was found to underestimate the experimental K L a for the reactor utilized by Boumansour and Vasel (1998) at various rotational speeds. The model proposed by Sant' Anna (1980) underestimated the values of K L a for the reactors utilized by various researchers, i.e., Zeevalkink et al (1979), Paolini (1986), Boumansour and Vasel (1998) and Kubsad et al (2004). On the other hand, the model was found to overestimate the values of K L a for the reactors used by Bintanja et al (1975).…”

Model for oxygen transfer in rotating biological contactor

“…As the molecular diffusion of dissolved gases is quite rapid, the dissolved gases would have the same concentration in the turbulent zone of RBC, even though there may be insufficient mixing occurring with respect to other pollutants. Further, studies on hydraulic regime indicate that complete mixing in RBC occurs which has been supported by tracer studies (Boumansour and Vasel, 1998;Shamaraja, 1997). Thereby the modified Kim and Molof model takes into consideration, the tank liquid volume and the actual disc surface area exposed to air.…”

“…Experimental parameters given by Sant' Anna (1980) are K=1.7; l=0.8; m=0.13; n= 0.74. Further the parameters (K, l, m and n) for Sant' Anna's model were also estimated by Boumansour and Vasel (1998) by using their own experimental data and results reported by Bintanja et al (1975), Zeevalkink et al (1979), Sant' Anna (1980), Poalini (1986) and Wuidar (1994) and they found the values to be K=2.673, l=0.769, m=0.135 and n=0.865. The coefficient of determination (R 2 ) obtained was 0.96 and they concluded that the difference between values obtained in their study and those obtained by Sant' Anna (1980) were not significant.…”

“…Kim and Molof (1982), suggested that the possible mechanism for the enhancement is due to direct oxygen absorption by the microorganism during the air exposure of the discs, whereas, Zeevalkink et al (1979), suggested that enhancement was due to increased oxygen diffusion in the liquid film induced by the oxygen consumption in the biofilm. The estimation of enhancement factor has been done by several researchers (Poalini, 1986;Radwan and Ramanujam, 1995;Boumansour and Vasel, 1998). In general, the previous researchers have suggested application of enhancement factor term (E) on the physical oxygen transfer to account for the increased oxygen transfer by the biomass.…”