Numerical evaluation of direct interfacial uptake by a microbial consortium in an airlift bioreactor

- Karst aquifers are susceptible to pollution that might be caused due to human activity.
- Surface water of sinkholes along Yucatan Peninsula is contaminated with hydrocarbons.
- ALB is a useful tool for the biodegradation of hydrocarbon using microbial consortium.
- 83.6% degradation of 20 g L-1 diesel is obtained in a 7 L Airlift Bioreactor (ALB).
- A direct interfacial uptake model of macroscopic oil droplets was used for experimental validation.

Sinkholes, also called cenotes, are a common feature in the karst aquifers found along the state Quintana Roo in México. Certain aliphatic and aromatic hydrocarbons have been found in the surface water of these sinkholes resulting in health and environmental hazards. In this study, a mathematical model is evaluated based on its predictive capacity on the biodegradation of oil in an airlift bioreactor (ALB). The model describes the oil uptake at the water-oil interface, whereas the previous modeling approaches focused on oil uptake in emulsified form. Biodegradation of 20 g L−1 diesel in an ALB is achieved by using an oil-degrading microbial consortium isolated from a sinkhole located in the urban zone of Playa del Carmen in Quintana Roo. The diesel degraded 83.6% confirming an effective use of ALB for the bioremediation of oil in water. The model is capable of predicting biomass growth and biodegradation by either integrating Monod or Teissier kinetics depending on the inhibitory effect of high concentration of oil on the microbial growth rate. The model is validated against three experimental campaigns performed in ALBs which indicated that it can serve as a valuable tool in the design and scale-up of bioreactors for the biodegradation of oil.