Aerated lagoon/adsorption combination method for the treatment of olive mill wastewater: optimizing parameters using study design.

Abstract

The current study focuses on investigating how to improve the efficacy of the combined process of aerated lagooning and adsorption for the treatment of olive mill wastewater (OMWW) from the olive industries in the Loukkos region using the design of experiments approach. The latter made it possible to optimize the experimental conditions, such as the mass concentration of lime, the mass concentration of powdered activated carbon (AC), and the speed of agitation (Va), which are required for the envisaged treatment, in order to control the results after the evaluation of the necessary physicochemical parameters, namely pH, total suspended solids (TSS), chemical oxygen demand (COD), rate of discoloration, and content of polyphenols. The experimental conditions necessary to carry out this study were between 1.4 and 1.75 g/l for AC, between 23 and 32 rpm for the stirring speed, and between 0.88 and 1.3 g/l for the mass concentration of lime. The results of this experiment showed that treating OMWW with the prototype II after adding lime to the mixture resulted in an estimated 85% reduction in the analyzed parameters. The pH, TSS, COD, discoloration rate, and polyphenol content were all reduced from initial values of 4.87, 0.63 (g/l), 80.3 (g (O2/l)), 0.8%, and 1.45 (g/l), respectively, to final values of 6.92, 0.12 (g/l), 12, 0.16%, and 0.25 (g/l). These results are highly significant when compared to those obtained during the treatment of prototype I using only powdered activated carbon, which showed a reduction rate of around 70%.