This study dealt with the problem of produced water (PW) at Missan Oil Company (MOC) which results in huge quantities of water annually from different fields of the company and particularly in Alommara oil field .The produced water is discarded to the evaporation ponds outside the field which causes serious problem to the environment. We studied that problem and how to treat the produced water generated from Alammara Degassing Station for reinjection application to increase the secondary oil recovery. A pilot plant (10m3/day) for PW treatment was manufactured based on some bench scale treatment to select the sequence process to treat the targets parameters. Many parameters were selected to be treated based on its effect on water injection specifications .The selected parameters were Oil and Grease , Iron ,Turbidity ,TSS, Particle Size , Dissolved Oxygen , PH and Bacteria. Removing oil by using corrugated plate interceptor technique (CPI) is the first stage of treatment. In some circumstances, the presence of iron in the produced water needs a treatment to meet the reinjected specifications of water. A chemical oxidant (Sodium Hypochlorite) was used in the pilot plant to oxidize the iron and removed later. The total suspended solids (TSS) are decreased to the required concentration by using coagulation – Flocculation process and dual sand filter media .The other target parameters to be treated in the pilot plant are bacteria and dissolved oxygen. Chemical agents, Gluteraldehyde and Sodium Sulfite were used to treat bacteria and dissolved oxygen respectively. Caustic Soda solution was used to obtain a suitable PH value. The specifications of treated water by this piot plant were very proper for safely reinjection to increase the recovery of oil.