Evaluating the Effect of the Wastewater Treatment Process in Water Treatment Plants (Case Study: Tehran's Seventh Drinking Water Treatment Plant)

Document Type : Research Paper


1 Department of Water Engineering and Sciences, Science and Research Branch, Islamic Azad University, Tehran, Iran.

2 Ministry of Energy Water Research Institute, Tehran, Iran.



The metropolis of Tehran has seven drinking water treatment plants, which according to the water needs, ‎more than one billion cubic meters of water treated by the treatment plants are provided to the customers ‎annually. Five percent of the volume of water entering the treatment plants is converted into wastewater, ‎which is estimated at 50 million cubic meters per year. If managed in the recycling process, it will play an ‎important role in balancing water resources and preventing water loss. Therefore, this study seeks to evaluate ‎the recycling process of water treatment in the field of drinking water supply in Tehran to increase the ‎stability of water supply and demand cycle. For this purpose, in order to effectively regenerate this cycle, it ‎was evaluated in the treatment plant No. seven in Tehran with an incoming water volume of 155 million cubic ‎meters per year. In this regard, the results of evaluation of the recycling process change in the treatment plant ‎showed that by changing the wastewater treatment process and the use of polyelectrolyte, the amount of ‎effluent decreased by 95%. The results showed that the volume of effluent decreased from 7.7 million cubic ‎meters per year to 310,000 cubic meters per year, which in fact, Five percent efficiency of effluent production ‎to three tenthe of percent of effluent production in this process change. This change in the effluent system ‎produced in the drinking water treatment plant can greatly contribute to the sustainability of water resources, ‎especially groundwater, given the volume of water resources required by Tehran.‎


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