Airlift bioreactors for bioremediation of water contaminated with hydrocarbons in agricultural regions

The superficial gas velocity (Ug) values of 1.0, 1.5 and 2.0 cm s−1 showed a diesel consumption of 59.70, 58.20 and 65.20 %, respectively. The productivity of the airlift bioreactors (ALBs) was 0.030, 0.026 and 0.034 g L−1 d−1, respectively. During 10 days of operation, the emulsification index (E 24 %) values for Ug 1.0, 2.0 and 2.0 cm s−1 were 15.79, 15.07 and 12.85 %, respectively. Likewise, an increase in the degradation and suspended solids was observed when increasing the Ug from 1.0 to 2.0 cm s−1 of the ALBs, whereas a decrease in emulsification index E 24 % was observed for an Ug of 2.0 cm s−1. According to the results, the Ug of 2.0 cm s−1 was the most effective for increasing the degradation of diesel and growth of the consortium among the Ug evaluated. Furthermore, the reduction of E 24 % in this Ug suggests that the consortium uses a mixed form of hydrocarbon consumption, both by direct contact and in emulsified form.