Nutrient removal in the effluent of manufacturing company is considered to be the major control parameter to prevent and reduce the risk of eutrophication and red tide problems occurring in lakes, reservoir, and coastal area. Twenty eight companies out of three industrial complex(Chungju, Yeochon, Iksan) producing more than 60㎎/L of total nitrogen(T-N) in the effluent were selected for detailed study. Existing treatment processes, concentrations of wastewater, and flowrate were throughly investigated. Mean values of T-N concentration from Chungju, Yeochon, and Iksan industrial complex were 297, 204, 1,613㎎/L, respectively. However, those concentrations were mostly influenced by one or few companies discharging significantly high nitrogen effluent Optimum treatment processes were proposed to bring the effluent nitrogen concentration below the regulated level using market-available technologies.