Recommendations for olive mills waste treatment in hot and dry climate

Abstract

Global olive oil demand is rising; hence production has been expanding, resulting in a considerable liquid waste known as olive mill wastewater (OMW) or Zibar, which has an adverse environmental impact as it contains a variety of pollutants. Proper control and treatment before disposal are essential. This study reviews the availability of international legislation and alternative techniques implemented worldwide to ensure safe OMW disposal and its applicability in hot climatic regions. Safe OMW disposal provides sustainable waste management throughout the entire chain of olive oil production. Three alternative techniques derived from legislations from high olive oil-producing countries have been evaluated using the strength, weakness, opportunities, and threats (SWOT) analysis by evaluating internal factors and investigating external factors to derive valuable strategies using Jordan as a case study. Those alternatives are switching to a two-phase continuous centrifugation system, land spreading, and lime pretreatment. The SWOT analyses yielded that shifting towards using a two-phase system would be a viable option for attracting funding agencies; the land spreading option can be applied if the risk of groundwater contamination is minimal, such as in the southern region of Jordan. Finally, before the evaporation ponds, lime pretreatment is a good option if the produced OMW is enormous such as the case in the northern region of Jordan, which has the highest mills number and produces a massive amount of OMW of about 66.3% of the total amount generated in Jordan.