The consumption and medicinal use of olive oil in the Mediterranean region is growing at alarming rate. However, olive mill wastewater threatens both aquatic organisms and human beings. Hence, there is urgent need to develop affordable treatment technology. In the present research, olive mill wastewater (OW) was collected from a three-phase olive production system located in the Karpaz region of Northern Cyprus. The collected OW was preserved and characterized before subjected to treatment. The chemical oxygen demand (COD) and phenolic content of the OW falls in the ranged of reported OW. Pre-treated olive oil solid cake (OC) and fabricated magnetically-responsive olive oil seed cake (MOC) were applied as adsorbents for treatment of OW by batch and column systems. The physico-chemical characteristics of the OC and MOC were evlauted and reported. The COD and colour of the OW were reduced using both OC and MOC under varying experimental conditions. The results herein, showed that MOC comparatively exhibited excellent performance and easy separation after use. Under optimum conditions in a batch and column systems, MOC reduces the COD to 6.5–8.9% and colour to 11.5–15.4%, while OC reduced the COD to 14.5–21.3% and colour to 27.6–33.5%. The MOC was reused severally with no significant loss in performance, suggesting that proposed treatment is technically and economically efficient. Keywords: Magnetic olive seed cake; olive mill wastewater, COD removal