Increased supply of desalination projects in Oman to meet demand

In July 2018 the opening of Oman’s largest seawater desalination plant on the coast west of Seeb marked a major step forward for the water utility sector. Completed in less than 30 months at a cost of $300m, the Barka IV independent water project (IWP) has a capacity of 281,000 cu metres per day. The Barka Desalination Company is a consortium made of Japan’s Itochu, French utility companies Suez Environnement and Engie, and local firm Towell Engineering. Water produced at the plant will be sold to Oman Power and Water Procurement Company (OPWP), the sole buyer of power and water for all IWP projects within Oman, under a 20-year water purchase agreement. While remarkable in its size and the speed with which it was built, this project demonstrates the global reach and singular importance of desalination in the sultanate’s water supply plans. This technology is now the focus of government efforts to combat both aquifer degradation and booming demand as the country’s population and water needs continue to expand.

Resources

As in other Gulf countries, Oman has no permanent surface rivers and experiences relatively little rainfall, with World Bank data showing an average precipitation of 87.3 mm per year from 1991-2015. Although seasonal khareef (monsoon) rains can sometimes fill wadis (valleys), for most of the year Oman is dry and sunny.

The only continuously flowing surface water is carried by a system of 3000 aflaj (irrigation channels) that access water from underground reservoirs and mountain springs, pumping it to local villages and towns. However, due to their age and the often complex local arrangements in place to maintain the channels, many of the aflaj are in need of repair. Indeed, of the average 552m cu metres delivered by these channels per year, around 23%, or 128m cu metres, is lost mainly due to leakage. In addition, recent reductions in rainfall, widely attributed to climate change, have led some 1095 aflaj to dry up, according to a 2017 survey by the Ministry of Regional Municipalities and Water Resources.

Major groundwater aquifers are managed by Diam, formerly known as the Public Authority for Electricity and Water, and contribute around 20% of the water used for domestic, industrial and agricultural purposes. There are 744 wells in the country, with groundwater resources mostly concentrated in the governorates of Al Dhahirah and Al Dakhiliyah, although these resources occur all around Oman. There are six major water basins ranging in size from 100m sq metres to 19.5bn sq metres. Recent projects in the Al Sharqiyah, Massarat and Najd basins have been undertaken to develop well networks.

In addition, there are some 31 recharge dams around the country. The Wadi Dayqah dam in the province of Qurayyat, south of Muscat, is the largest with a storage capacity of up to 100m cu metres, provided by seasonal flood waters. Total surface water as a result of dam water storage is estimated at 102m cu metres and contributes 6% of total supply.

Growing Demand

As Oman’s population has expanded, so has its water consumption. The population has nearly doubled over the past decade, from 2.76m people in 2008 to around 4.61m people as of June 2018, according to the National Centre for Statistics and Information. This rapid population growth has put pressure on existing water systems by depleting aquifers faster than they can refill.

The Al Sharqiyah Basin, for example, has an estimated total demand of 80m cu metres per year, although the total capacity of the groundwater recharge – the amount that can be replenished with rainfall – is just 65m cu metres per year.

Government officials project that water demand will continue to grow by 6-8% per year through to 2022, as the population and living standards continue to increase. With the country’s largest conurbations on the coast, water withdrawal and non-replenishment has also led to a growing problem of saline water intrusion and a depletion in water quality.

The impact on rural communities has also been felt, with fields drying up and farmers moving to urban areas. This not only adds pressure to urban water systems, but also causes agricultural prices for domestically produced fruit and vegetables to spike.

Keeping the Balance

Omani officials are aware of the problem, prompting the development of alternate sources, such as desalination and wastewater treatment. Water is currently sourced from four major desalination sites in Oman: Ghubrah, Barka, Sohar and Sur. The first three serve Oman’s Main Integrated System, while Sur serves the needs of customers in Al Sharqiyah, where there is a separate, extensive water transmission system. The plants themselves are run as independent power and water projects, and use a mix of multi-stage flash distillation and reverse osmosis (RO) technologies.

The first method is an older technology, which involves boiling the seawater and collecting and cooling the vapour. The desalinated water is then re-mineralised and chlorinated before being distributed. Desalination plants using this method include the Sohar power and water desalination plant, with a capacity of 33m imperial gallons per day (MIGD), and the 42.5-MIGD Barka I Power Plant.

The RO method, meanwhile, uses a series of semi-permeable membranes to separate the salt from the water. RO is generally preferred these days as it is far more energy efficient, with the new Barka IV plant having a record low electricity consumption per litre of water. Desalination plants that use RO include the 26.4-MIGD Barka II power and desalination plant, the 15-MIGD Salalah power and desalination plant, and the 17.7-MIGD Sur desalination plant. The 31-MIGD Ghubrah power and water desalination plant uses both RO and flash distillation; however, the facility is gradually being upgraded to use RO technology. In 2017 the 42-MIGD Ghubra II came on-line, using solely RO technology.

Recent plants also pay careful attention to reducing their environmental impact. At the Sur plant, for example, seawater is collected from 28 beach wells, which draw water from 80 metres below the surface, thereby minimising harm to coastal habitats and marine life. Preserving the local ecological balance is crucial as recent episodes with a major algae bloom have shown. In 2018 a sudden algae growth along the coast of the Al Batinah region forced the Barka I desalination plant to run below capacity, resulting in OR140,000 ($364,000) in losses.

Meeting Needs

Diam has a series of expansions in the pipeline to provide water, with Barka IV marking the first of 10 planned desalination plants by 2023. The Sohar III desalination plant, a 250,000-cu metre-per-day facility, is due for completion before the end of 2018. Expected to meet 80% of the water demand in Al Batinah North, Sohar III is being developed by the Myah Gulf Oman Desalination Company, a consortium led by majority shareholder Valoriza Agua of Spain, the Oman Brunei Investment Company and engineering firm Sogex Oman.

Further developments at Sohar Port includes Oman Sustainable Water Services (OSWS), a joint venture between Spain’s Aqualia and the Omani state-owned Majis Industrial Services. OSWS will construct a 20,000-cu-metre-per-day desalination plant, a 10,000-sq-metre-per-day wastewater treatment centre, water and sewage networks, and hydraulic pumping and process systems for the port’s operation and maintenance.

In July 2018 the build, own and operate contract for the $180m plant at Al Ashkharah in Al Sharqiyah governorate was awarded to the Al Asilah Desalination Company, which is 75% owned by Japan’s JGC Corporation, 20% by the United Infrastructure Development Company and 5% by South Korea’s Doosan.

Meanwhile, Ghubrah III is set for completion in 2022 and will add another 300,000 cu metres per day of capacity to the system. In August 2018 the OPWP short-listed eight companies for the project and is set to launch tenders before the end of 2018.

In August 2018 OPWP signed agreements for a new OR60m ($155.8m) plant in Salalah with a consortium consisting of Saudi Arabian developer ACWA Power, with a controlling 50.1% stake; Veolia Middle East, with a 35% share; and the Dhofar International Development and Investment Holding Company, with 14.9%. The plant, which is set to begin production in 2020, is being constructed on the Ashur Plain in Mirbat, and will have a production capacity of 113,650 cu metres per day.

A $250m, 200,000-cu-metre-per-day facility in Qurayyat will be run under a build, own and operate contract by a consortium led by Singapore’s Hyflux, which has an 85% stake. The plant was due to begin operations in 2017, but has been delayed by technical issues, while Hyflux looks for additional funding.