The sewage has a lot of pollutants. The existence of high density nutrients and organic materials are the most problematic issues of sewage. This research deals with the purification of organic materials and nitrogen from sewage by the use of biological and electro fenton processes at the same time. In biological process, one anoxic reactor and three oxic reactors are used. The volume of each reactor is 6 liter. In this process, recycling from oxic to anoxic reactor is substituted by recycling from the sludge of settling tank to the anoxic reactor. After 70 days of startup the system, the anoxic reactor location was changed, and it was placed in the oxic reactor. In each stage, the removal efficiency of Chemical Oxygen Demand (COD), ammonia was investigated. In the pre-anoxic, the efficiency of COD and ammonia removal from wastewater were 75% and 95%, respectively. The COD and ammonia removal efficiency from wastewater in the post-anoxic were 78% and 94%, respectively.In the next step of this experiment, to investigate the treatability of raw wastewater by electrofenton process and improvement of biological removal efficiency, effluent from the biological process were studied by electro fenton process. In electro fenton process, some parameters such as H 2 O 2 volume, current density and pH were considered in three levels, also time was considered in four level as effective and important. The effect of these parameters on COD and ammonium and nitrate removal efficiency were studied. This process was done by the use of Response Surface Methodology (RSM) and Design-Expert Sofware version 10.0.3.1and all the effective parameters were detected. In The optimization process, raw wastewater removal efficiency of COD, nitrate, and ammonia were measured 83%, 50%, and 46%, respectively. Also in the optimized condition of the process in treated wastewater the efficiency of COD, nitrate were equal to 71% and 23% respectively.At the end of the process, the coliform test is done in order to study the effect of coliform removal from sewage on the wastewaters of biologic and combined processes. The result showed that the amount of coliform in raw sewage reduced from 230000 MPN/100ml to 360 MPN/100 ml in biological process and 61 MPN/100 ml in electro fenton process. Key Words: Anoxic, Oxic, Electro Fenton, Nitrate, Ammonium, COD, Response Surface Methodology (RSM)