Introduction

Isfahan Water Supply Company (IWASCO) plans to build seawater intake facilities and desalination plants with a production capacity of 1,800,000 cubic meters per day (equivalent to 600 million cubic meters per year) in its long-term plan. The selected desalination system for this project is reverse osmosis (RO), which will be built in 3 phases and in each phase, three desalination plants will be built in 3 different stages consecutively. The system of seawater intake and discharging waste water is considered independently for each phase, which consists of three desalination plants. The raw water required for phase one is 1,850,000 cubic meters sea water per day (77,000 cubic meters per hour), which is taken from the sea of Oman and after desalination, it is transported to Isfahan province through pipelines. The production capacity of each stage of each phase is 200 thousand cubic meters per day of product water, thus at the end of each phase 600 thousand cubic meters per day (equivalent to 200 million cubic meters per year) of product water will be produced and in the final horizon of the plan at the end of phase 3, The amount of product water production will reach 1,800,000 cubic meters per day (more than 600 million cubic meters per year). The seawater intake system, which will be built at a designated location 10 kilometers north of Sirik city in Hormozgan province, will supply the raw water needed for desalination plants. The main method considered for seawater intake is the gravity-based sub- surface extraction method, using semi-buried pipelines on the seabed and suction chambers. The seawater intake system consists of marine suction chambers, submarine intake pipelines and an onshore pumping basin. The sea water enters the basin by gravity through marine suction chambers and submarine pipelines, and after chlorination and passing through the filters of the intake facilities, it is transferred to the pumping pond and delivered to the desalination plants by vertical pumps. Product water is produced by reverse osmosis (RO) method and with drinking water standards. A storage tank and a common pumping station will be built for all three desalination plants, and finally, the product water will be transported to consumption centers in Isfahan province through a pipeline with a length of approximately 1200 km. At this stage, i.e. the first stage of phase- I of the project, the employer has the construction of the following facilities in his implementation plan:

• Construction of seawater intake facilities based on the water required for three desalination plants
• Construction of one desalination plant with daily production capacity of 200,000 cubic meters of product water (according to drinking water standards)