Kinetics of hydrolysis, oxidation, and adsorption during olive oil degradation by activated sludge

Kinetics of the degradation of olive oil by an acclimated activated sludge were studied. Kinetic constants for the lipid removal from the mixed liquor and for that from the supernatant and for the hydrolysis step were evaluated using Michelis-Menten equations. The maximum specific reactions rates (v(max)) and the saturation constants (K(m)) were v(max) = 1.20 mg lipid mg(-1) MLVSS day(-1) and K(m) = 1290 mg/L for lipid removal from the mixed liquor; v(max) = 1.54 mg lipid mg(-1) MLVSS day(-1) and K(m) = 801 mg/L for that from the supernatant; v(max) = 1.57 mg olive oil mg(-1) MLVSS day(-1) and K(m) = 1750 mg/L for the hydrolysis of olive oil (where MLVSS refers to mixed liquor volatile suspended solids). The adsorption of olive oil by the activated sludge contributed to the lipid removal from the supernatant. The specific rate of this adsorption was also estimated. The hydrolysis, rather than the oxidation of free fatty acids, was the rate limiting step in the degradation of olive oil when the concentration of olive oil was lower than about 800 mg/L.