Seyed Masoud Tayefeh Cheraghali - Graduate Faculty of Environment, University of Tehran, P.O.Box ۱۴۱۵۵-۶۱۳۵, Tehran, Iran.
Amin Sarang - Graduate Faculty of Environment, University of Tehran, P.O.Box ۱۴۱۵۵-۶۱۳۵, Tehran, Iran.
Mohammad Ali Zahed - Department of Civil Engineering, Auburn University, Auburn, AL ۳۶۸۴۹, United States of America.
Hossein Vahidi - Department of Industrial Ecology, Academic Center of Education, Culture and Research(ACECR),Sharif University Branch, Tehran, Iran.

One of the main problems in the quality control of rivers is the high control cost imposed upon pollutant units. The cooperative policy approach in the treatment process between two or more pollutant units is a new and economic perspective in the environmental management of catchment basins. Origins of large amounts pollutants which require a high cost to control pollution are trying to start partnerships with smaller units in establishing joint refineries in order to reduce their own and the whole system s costs. In this study, considering the one way direction of the river s water, the Streeter – Phelps equations were used to simulate the river. The Ant Colony Optimization was used as an efficiency model in order to acquire the best scenario of cooperation based on the maximum elimination of pollution and reduction of treatment costs without straying from the river s quality standards. Also the ratio – trade system was used for commercial purposes. After this the cost of the depleting units was split evenly between them using the cooperative game theory. The efficiency of the model was evaluated by qualitative and quantitative analysis of the Zarjub River in Gilan province of Iran. Three main scenarios were taken to mind for cooperative trading to take place. Carrying out the trade – partnership model could play positively large role in sufficing the quality the control of river water.

partnership model, Ratio – trade system Ant Colony Optimization Theory of cooperative game