Salalah is gearing up to meet the future requirements on all fronts due to the fact that large scale development is happening across all sectors. The trend suggests arrival of new industries and much more touristic activities with the broadening of transport networks. An important initiative has been taken by the Salalah Sanitary Drainage Services Company (SSDC), a wholly owned government entity of the Sultanate of Oman, to upgrade Salalah's drainage facility from existing 35,000 cubic metres per day to 69,000 cubic metres of waste by 2021.
The facility is being developed by Turkish company STFA, an investment holding group providing services in the construction, energy and construction equipment sectors, while consultants are Al Manarah Engineering Consultancy. This is an emergency marine outfall facility which is useful in case of failure of a water reclamation plant, failure in the network or overflow in case of storms or any other reasons. "The dredging underwater project is closer to the Port of Salalah in which about 4,500 metres of various range size (1,200mm diameter to 800mm diameter) high-density polyethylene (HDPE) pipes would be installed under water and 1,500 metres on the ground," said Ediz Dundar, Project Manager of STFA.
"The emergency marine outfall project would work as a support to an established sewer network and treatment facility which is operational since 2002. The domestic sewage wastewater has an average hydraulic load of about 23,000 to 27,000 cubic metres per day. During the Khareef the average load can reach 35,000 cubic metres per day. However, the load is expected to increase due to the demographic development and an increase in tourism," said Dundar.
This is a good initiative on the part of the Salalah Sanitary Drainage Services Company to increase the capacity of the sewage treatment plant to meet the demand for treatment of the future waste water flows.
The first phase of expansion works has recently been completed to increase the capacity up to 35,000 cubic metres per day. A second phase of expansion work shall increase the capacity to 60,000 cubic metres per day by year 2021.
Incorporating changes required to the design provided to reflect any requirements that may be raised by any of the concerned authorities, or to accommodate site conditions that are not reflected in the design drawings.
Upgrading of the main pumping station (MPS-1), while keeping the pumping station operational is also the part of the project. This will include construction of twin force mains from the main pumping station MPS-1, connecting to the emergency marine outfall.
Interface between emergency outfall and replacement of MPS-1 twin force mains is part of Package II contract. The Package II contract is aimed at upgrading the current DN600 DI twin force mains from MPS-1 to the water reclamation plant with twin OD710 HDPE force mains.
As part of procurement and installation of surge vessels there would be construction of chambers for valves, air valves and flow metres. It also involves construction of air trap chambers, air trap pipe and valves and installation of crane in the pump room.
The project will undertake offshore trenching (maximum trench depth approximately 2.5m) to a water depth of minimum 12 m to cover the offshore marine outfall in the surf zone and installation of the off-shore marine outfall pipe on the seabed outside of the surf zone and stabilising the pipeline with concrete ballast.
"There would be installation of a diffuser system at the end of the off-shore marine outfall pipe and marking (no anchoring zone) and protection of the outfall pipe. The project would establish connection to an existing SCADA system, protection works around wadi crossings and protection works around existing utilities," he said.
The project also aims at repairing and re-instatement of road surfaces back to original conditions, testing and commissioning of the works and providing on-the-job training to Omani staff to make them capable of managing the outfall.