Assessment of the impact of the three different methods of crushing olives on the microbiological and physicochemical properties of wastewater in olive mills

Abstract

Liquid olive waste presents one of the major problems for the environment in olive oil-producing countries. The goal is to identify the crushing method that decreases the environmental impact, particularly in terms of the organic loading and microbial contamination to guide the future treatment and recovery strategies. The results obtained from the chemical oxygen demand (COD) have shown that the continuous three-phase system exhibited the highest COD value, reaching 31 × 10⁴ mg O₂/l, and a concentration of 13 × 10³ mg/l for polyphenols and 2137.4 mg/l for hydroxytyrosol. The microbiological study is yeasts, fungi, and bacteria in the three methods. The two-phase method had the highest microbial load with great concentrations of nitrogenous compounds. As a result of the preservation of our environment, we see that the two-phase method represents the least polluting method, compared to the other methods.