Influence of Activated Carbon–Remediated Olive Mill Wastewater on Germination and Early Growth of Barley and Fenugreek

Abstract

The disposal of olive mill wastewater (OMW) poses significant environmental challenges because of its high organic load and phytotoxic compounds. This study focused on treating OMW from a modern oil mill using a filtration-percolation technique and evaluated its impact on the germination of barley and fenugreek seeds. Filters were prepared using lime and charcoal derived from the mill’s pomace. Four distinct treatments were applied: (1) raw OMW (T0), (2) a lime layer (1.0 cm) sandwiched between two layers of sand (T1), (3) an activated charcoal layer (1.0 cm) derived from pomace sandwiched between two layers of sand (T2), and (4) a combination of lime and activated charcoal derived from pomace, sandwiched between two layers of sand (T3). Extensive physicochemical analyses, including pH, electrical conductivity (EC), total suspended solids (TSS), moisture content (MC), dry matter (DM), total Kjeldahl nitrogen (TKN), biochemical oxygen demand (BOD₅), phosphorus (P), polyphenol (PP), and exchangeable cation content (Ca, Na, and K) were performed. The results revealed significant differences between treatments, with substantial reductions in polyphenols, EC, organic matter (OM), total organic carbon (TOC), and BOD₅. Treatments T2 and T3 were the most effective depollution of OMW, and T3 exhibited the highest germination rate. These findings highlight the potential of this filtration technique for treating OMW and promoting its reuse in sustainable agriculture.