Chlorinated Sea Water is a vital utility service which provides uninterrupted supply of seawater for non-contact process cooling applications to the industries in the Sohar Industrial Port Area.
The Sea Water Intake and Return System-1 (SWIRS-1) is designed to produce approximately 334,000 cubic meters per hour of screened chlorinated seawater for distribution at the pumping station.
With SWIRS-1 almost fully allocated to off-takers we are on the way to build SWIRS-2 to produce approximately an additional 324,000 cubic meters per hour of chlorinated sea water. SWIRS-2 is expected to be commissioned by mid 2009.
For smaller volume customers a delivery network is being built through which sea water will be pumped and made available at the battery limit of industries.

The SWIRS design allows for smooth flow of seawater through a dredged canal built between two break water with a total length of 1800 meters and stretched 600 meters into the sea .Approximately 1 million tone of stones has been used in the construction of the break water and about 380,000 cubic meter of dredged material was removed from the intake. Due to the rapid development in the Sohar Industrial Port Area, provision for future demand was considered by way of widening the channel during the construction of the break water to accommodate another pumping station. The existing Intake capacity is approximately 700,000m3/hr which is sufficient to satisfy projected demand requirements.

An oil boom barrier placed at the mouth of the intake prevents the ingress of any spilled oil along with the seawater boom entering the pumping station.

The design allows a smooth inflow of seawater through screening chambers. These act as filters to keep marine life out of the pumping station. As a backup measure, Hypo chlorite solution is continuously injected into the inflow of water. The strong solution kills any marine life that escapes the screening chambers.

They have 10 screening chambers each with one rake bar and one band screen. Four screen bays are placed in the centre while three are on either side.

The water passes through rake bars and reaches a section fitted with screen bars spaced at 30 millimeters, which block passage of dead marine life and waste material.

Distribution bays supply water to 48 pump chambers allotted to 13 Users in 12 different corridors. Each pump chamber can draw water up to a maximum of 16,000 cubic meters per hour. The width of each chamber is 4 meter.
Water enters the four distribution bays where baffle walls eliminate the formation of eddies and swirls and regulates the water flowing towards pump chambers.

A Chlorine production and injection station with a production capacity of 702 kg/Hour of hypochlorite solution is constructed to provide the required chlorine for the processing and disinfection of the seawater. The station is equipped with 8 lines of hypochlorite production generators consisting of a transformer, rectifier and electrolyser.

The hypochlorite solution is injected automatically as per the required concentration. Online measurement and monitoring equipment are installed and connected to the control room to allow proper data management.

The pumping station is equipped with buildings to facilitate the operations of the facility. Administration offices, control and inspection rooms are in place together with a special structure to maintain giant dam board that could weigh up to 7400 Kg.

The system is equipped with instrumentation facilities to allow continuous monitoring of the difference in the level of natural seawater.

The return is by way of routing through a Open Seawater Canal to the Return System(s) at the coastline. Environmental Impact assessment studies have been carried out to ensure that there are no adverse effects to the environment. In compliance with environment rules and regulation, Industries are not allowed to discharge water at temperature higher then 10°C from intake water, or to discharge any other water different in its specification from the seawater quality.

As an integral part of the development of the design for the intake pumping station an investigation involving the use of a physical model was carried out in order to evaluate the hydraulic performance of the proposed pumping arrangement. Studies also include computational modeling of sediment transport and wave disturbance in the intake. Assessment of the impact on the local shoreline as a result of the construction of the SWIRS and a thermal dispersion simulations was carried out in order to assess compliance of the discharge with the Oman environmental standard.

The project faces sudden attacks continually from hundreds of tons of jellyfish. Colonies of jellyfish clog the screens and mechanical parts leading to a total shutdown of the pumping station as well as the industries. But the unique design of this project provides a contingency plan to prevent such jellyfish ingress. During an attack, the speed of the rake bar screens is increased according to its intensity. Like all other waste, the jellyfish are collected in the trash channel and are chopped and collected in the solid handling area. The waste is then disposed off in a pre-designated area.