Kinetic modeling of carbon and nutrients removal in an integrated rotating biological contactor-activated sludge system

Abstract

In this study, kinetics of biological carbon, nitrogen, and phosphorous removal from a synthetic wastewater in an integrated rotating biological contactoractivated sludge system was investigated. The experimental data obtained from varying four significant independent factors viz., hydraulic retention time, chemical oxygen demand for nitrogen to phosphorus ratio, internal recirculation from aerobic to anoxic zone and disks rotating speed were used for the process kinetic modeling. In order to obtain the bioprocess kinetic coefficients, Monod, firstorder and Stover-Kincannon models were employed. As a result, Monod and Stover-Kincannon models were found to be the appropriate models to describe the bioprocess in the rotating biological contactor-activated sludge system as the determination coefficient for the first-order model obtained less than 0.79. According to the Monod model, growth yield, microbial decay rate, maximum specific biomass growth rate, and half-velocity constant coefficients were found to be 0.712 g VSS/g COD, 0.008/d, 5.54/d and 55 mg COD/L, respectively. From Stover-Kincannon model, the maximum total substrate removal rate constant and half-velocity constant were determined as 15. 2, 10.98, 12.05 g/L d and 14.78, 7.11, 6.97 mg/L for chemical oxygen demand, nitrogen and phosphorus removal, respectively. The kinetic parameters determined in this study can be used to improve the design and operation of the biological contactor-activated sludge system in full scale.

Kinetics of nutrient removal in an on-site domestic wastewater treatment facility

“…The saturation constant (KB) and the maximum utilization rate (Umax), the rate constant in Stover-Kincannon model, were found to be 316.33 mg/L.d and 166.66 mg/L.d, respectively. Comparing with the results found by Akhbari et al (2012) [12], in this study, KB and Umax values was much lower, but the correlation coefficient was in the similar value. The correlation coefficient (R 2 ) in this model was 0.97 which consider as higher precision than the firstorder model.…”

“…Therefore, the higher the k2(s), the faster the pollutant can be removed. k2(s) (0.1522 d -1 ) obtained in this study was lower than the one obtained by Akhbari et al (2012) [11].The k2(s) will be increased as substrate removal rate increased depending on initial substrate concentration and microorganism inside the reactor.…”

“…This expression can be solved for either the effluent substrate concentration (12) or the removal efficiency of the reactor (13) by substituting kinetic constants Umax and KB.…”

“…Akhbari et al (2012) [12].The k2(s) will be increased as substrate removal rate increased depending on initial substrate concentration and microorganism inside the facility. Simplified models are formed a few variables and can be used to determine the kinetic of the reactions.…”

Post-aerobic digestion of waste sludge: performance analysis and modelling of nitrogen fate under alternating aeration

“…According to the IWA task group on modelling (Henze et al 1987;Akhbari et al 2012), a Michaelis-Menten-like kinetics was assumed and the limiting effect of dissolved oxygen has not been included in the kinetic equations being the oxygen furniture ensured in excess during the aerobic batch tests. It is worth noting that as it is common practice for biological processes, proposed models are based on ''lumped'' (or apparent) parameters, that is, parameters accounting (besides the kinetics) different phenomena such as mass transfer resistances for substrates and oxygen, and inhibition phenomena.…”