Organized industrial estates (OIEs) have been supposed to an alternative to industrial pollution control, in particular, in developing countries. However, a wastewater management strategy should be well established in the planning phase of them to save investment and operational costs of the central wastewater treatment plant in the estate. In this study, a medium-large scale OIE established in Sivas (SOIE), in the north east Turkey where a great number of OIEs settled or under construction is handled to characterize and chemical treatment of its effluent. The wastewater characterization was carried out by taking eleven 2-h composite samples from the end-pipe and five samples from the priority industries localized in the estate during 2002. The measured characteristics were also compared with those obtained based on literature studies to emphasize the importance of the in-situ characterization. Furthermore, those measurements were compared with the values measured during 2005 at the end-pipe. Due to varied wastewater flow and characteristics, coagulation process using aluminium sulphate, ferric chloride and ferrous sulphate salts was evaluated as pretreatment to comply with the discharge limits. All types of coagulants were effective to achieve high removal efficiency of COD (> 70%) whereas none of the coagulant assured required TSS (< 50%) removal. According to required removals of COD and TSS the use of FeSO4 (being the cheapest one) was assessed the optimum coagulation for the present loads as a pretreatment. Recent COD and TSS values measured also were fluctuating in a wide range, however, not increased significantly, therefore, a pretreatment control for metal industries should be considered.