en Environmental Health, Sciences, and Engineering Environmental Health, Sciences, and Engineering Review Review Article <div style="text-align: justify;"><span style="line-height:1;"><span style="font-size:14px;"><span style="font-family:Times New Roman;"><b><span style="color:black">Background:</span></b><span style="color:black"> The olive production industry is experiencing rapid growth owing to its health advantages. Nevertheless, a major challenge it encounters is the highly variable wastewater generated from olive oil mills (OMW). To tackle this issue, a range of treatment methods has been adopted, which include physical, thermal, biological, physicochemical, and biophysical treatments, as well as sedimentation, advanced oxidation processes, and combined approaches. This review emphasizes recent studies concerning techniques aimed at eliminating contaminants from OMW.</span><br> <b><span style="color:black">Methods:</span></b><span style="color:black"> This review paper provides an overview of the approaches and technologies used to treat and recover OMW, based on an analysis of 50 peer-reviewed articles published between 2000 and 2025. </span><br> <b><span style="color:black">Results:</span></b><span style="color:black"> OMW is characterized by high concentrations of salts (10 dSm^-1), organic matter (130,000-200,000 mgL^-1), suspended solids (2170-3480 mgL^-1), and particularly phenols (360 mgL^-1). It also exhibits high biological oxygen demand (18,000-77,000 mgL^-1) and chemical oxygen demand (160,000-180,000 mgL^-1). Typically, OMW is dark brown with a foul odor and contains significant amounts of organic and inorganic compounds, such as potassium (2700-7200 mgL^-1), phosphorus (300-1100 mgL^-1), and lipids (3.0-23 mgL^-1).</span><br> <b><span style="color:black">Conclusion:</span></b><span style="color:black"> The complexity of OMW shows that the scientific community has yet to determine a definitive treatment method. Combining technologies such as precipitation, adsorption, advanced oxidation, and membrane filtration</span> <span style="color:black">has been shown to enhance the treatment of OMW.</span></span></span></span></div> Advanced oxidation processes, Filtration, Electrocoagulation, Aerobic treatment, Anaerobic treatment, Adsorption, 13 24 http://jhehp.zums.ac.ir/browse.php?a_code=A-10-122-10&slc_lang=en&sid=1 Mohammad Reza Shojaei shojaei@znu.ac.ir 100319475328460016217 0009-0008-5798-1555 No Department of Environmental Sciences, Faculty of Science, University of Zanjan, Zanjan, Iran. Abbasali Zamani Zamani@znu.ac.ir 100319475328460016218 100319475328460016218 Yes Department of Environmental Sciences, Faculty of Science, University of Zanjan, Zanjan, Iran. Armin Fashi arminfashi@alumni.znu.ac.ir 100319475328460016219 0009-0008-5741-3355 No Research and Development Unit, Glucosan Company, Alborz Industrial City, Qazvin, Iran. Mehdi Shojaei mehdishojaei@ut.ac.ir 100319475328460016220 100319475328460016220 No Aran Zino Mahan Company, Zanjan, Iran.