Improvement of biological process using biocoagulation–flocculation pretreatment aid in olive mill wastewater detoxification

AbstractOlive mill wastewaters (OMWW) are a significant source of potential or existing environmental pollution in the Mediterranean countries. Treatment and reuse of OMWW present significant challenges, both due to the nature of olive oil production (seasonal and concentration in a small scale) and due to the characteristics of the wastewater (high chemical oxygen demand (COD) and high phenolic content). In the present work, experiments of different pretreatment methods were undertaken and compared in order to select the most adequate process to be applied before biological treatment of OMWW. In fact, three different pretreatments were tested and compared: two different coagulants (alginate and Kim2120) and electrocoagulation (EC) process. At the second stage, biological treatment (using white-rot fungus) was investigated. Tests were conducted with raw OMWW and with OMWW diluted in 50% tap water and adjusted to a neutral pH with lime. The raw effluent presents high COD (178 g O2 l−1), about 6.4 g l−1 of ...