Biogas Production from Olive Mill Wastewater: Biotechnological Development for Circular Economy

Author(s): Uri Marchaim, Dan Levanon

This study presents a full-scale approach to treat olive mill wastewater (OMW), reducing pollution through thermophilic anaerobic fermentation, yielding biogas for electricity and heat, slurry to substitute for peat moss, and partially purified wastewater for irrigation. These outputs align with the EU’s Green Deal strategy by supporting energy independence, wastewater valorization, and climate change mitigation. As a result of the pilot treatment, 93% reduction in chemical oxygen demand (COD) levels and 91% reduction in polyphenols was achieved. OMW slurries can substitute at least 30% of the peat moss in lettuce cultivation. In the economic theoretical analysis performed, we estimated the costs and profit, based on pilot expenses, and found that a full-scale regional central facility can achieve a positive net present value (NPV) (€1,239,234) and high internal rate of return (IRR) (42.49%). In the context of the circular economy out-lined here, collaboration among olive oil producers and the local wastewater utility, using OMW for bioenergy and utili-zation of all outputs, can lead to innovative regional business models. We offer a framework for developing sustainable, regionally adapted bioenergy business models and assesses critical variables affecting stakeholder cooperation and pro-ject viability.