Water Air Soil Pollut (2016) 227:135 DOI 10.1007/s11270-016-2837-8 Treated Olive Mill Wastewater Effects on Soil Properties and Plant Growth Munir J. M. Rusan · Ammar A. Albalasmeh · Hanan I. Malkawi Received: 24 January 2016 / Accepted: 28 March 2016 © Springer International Publishing Switzerland 2016 Abstract Olive-oil production has a vital impact on the socioeconomic development in most Mediter- ranean countries, where 97.5 % of the world oil is produced. However, the olive-oil extraction process generates considerable quantities of an agro-industrial effluent, olive mill wastewater (OMW), which has negative impact on the environment and biological life. The objective of this study was to evaluate the potential use of OMW treated by different technolo- gies in irrigation and determine its effect on the plant growth and soil quality parameters. Different tech- nologies were used to treat the OMW, the resultant treated OMW was used to irrigate the maize planted in the pot experiment. The results indicated that UOMW increased soil salinity and reduced plant growth, while the treated OMW by different technologies improved plant growth and resulted in lower soil pH. The impact on other soil properties varied depending on the tech- niques used for treatments. Although treated OMW enhanced plant growth compared with the untreated, the plant growth remained lower than that obtained M. J. M. Rusan () · A. A. Albalasmeh Department of Natural Resources and The Environment, Faculty of Agriculture, Jordan University of Science and Technology, Irbid, Jordan e-mail: mrusan@just.edu.jo H. I. Malkawi Hamdan Bin Mohammed Smart University, Dubai, United Arab Emirates using the potable water with fertilizers, indicating lack of some essential plant nutrients. Keywords Olive mill wastewater · Plant growth · Reverse osmosis 1 Introduction Olive-oil production has a vital impact on the socio- economic development in most countries of the Mediterranean basin, where 97.5 % (more than 30 million cubic meters) of the world oil is produced with annual growth of 6 % between 2007 and 2012 (Marinelli and Oreggia 2013; Mekki et al. 2006). The olive-oil extraction process generates a considerable quantities of agro-industrial effluent known as olive mill wastewater (OMW). Olive extraction process nor- mally generates olive-oil (20–32 %), aqueous phase (40–50 %), and solid byproduct (30 %) (Borja et al. 1992). OMW contains a large supply of organic matter and toxic phenolic compounds. Because of the high lev- els of polyphenols concentrations (0.5 to 25 g l -1 ) and other toxic organic load, OMW is considered a toxic such that the improper disposal of OMW imposes seri- ous problems to the environment and public health (Azam et al. 2002). Polyphenols in OMW are phy- totoxic and known to have a plant growth inhibition properties and antibacterial effect thus prohibiting its