Having a small population has in the past helped Bahrain’s government stay ahead of demand for public services. The island kingdom has enjoyed centralised wastewater collection and treatment since the 1970s, when the first plants were commissioned.
About 90 per cent of the population are now connected to the sewerage network, with the remainder relying on septic tanks. The gov-ernment aims to increase network coverage to 99 per cent of the population by 2015.
This task is not without challenges. The population of Bahrain recently topped 1 million and is growing at more than 2 per cent a year, causing the authorities to review their services provision. A German consortium, made up of P2M Berlin, GTZ and Dornier Consulting, was appointed in 2008 to draw up a wastewater masterplan for the kingdom. Its task is to assess the demand and forecast the investment that will be required by Bahrain’s wastewater services up to 2030.
Previous forecasts have been set aside. A similar plan published in 1998 predicted that the population would grow to 1.1 million by 2020 – a figure Bahrain is expected to exceed in 2010.
Rapid economic development in 2005-08 has also boosted demand for water and wastewater services. Land reclamation projects off the main island’s northern and eastern coasts account for a large part of this new demand. Major developments on Muharraq Island, where population growth is forecast at 7 per cent a year, are also expected to increase demand.
The German study, due to be presented in 2010, is expected to recommend using treated sewage effluent to replenish the water table, in a process known as groundwater recharge, making more water available for irrigation. Currently, most irrigation on the island – Bahrain has extensive farms on its northern and western coastlines – uses desalinated water.
It is a commercially attractive option. The cost of treating effluent is about $0.13 a cubic metre, compared with the $0.79 a cubic metre cost of buying drinking water from the Water Supply Department.
An estimated 200,000 cubic metres a day (cm/d) of treated sewage effluent was produced in Bahrain last year for irrigation, a figure forecast to rise to 350,000 cm/d over the next five years. Sludge production in the kingdom averaged about 30 tonnes a day of dry solids, most recycled for agricultural use, with the rest going to landfill.
Besides expanding wastewater network coverage, Bahrain’s government aims to more than double treatment capacity to 500,000 cm/d by 2015. Bahrain currently has two major sewage treatment plants – one at Tubli and the other in the industrial area of Sitra – plus a further seven smaller facilities. The Tubli Water Pollution Control Centre is by far the largest, serving 600,000 people. At times, it has to process well above its design capacity of 200,000 cm/d, with peak flow in 2008 reaching 322,000 cm/d.
“Bahrain’s government aims to more than double treatment capacity to 500,000 cm/d by 2015”
The result has been a deterioration in the quality of treated sewage effluent, which is causing pollution when it is discharged into the Gulf. As a result, Bahrain’s Ministry of Works has brought forward plans to upgrade and expand the Tubli plant, and work is under way to expand its capacity to 350,000 cm/d. Construction work on the $120m project is due for completion by 2015.
As part of the upgrade, the tankered waste plant at Tubli will be decommissioned and a 10,000-cm/d unit will be installed at the Al-Dur sewage treatment plant. The contract will be carried out on a five-year operation and maintenance basis, as will the main contract to expand Tubli. The 12,500-cm/d plant at Sitra is also being expanded, with capacity due to reach 16,500 cm/d by the end of the year. Bahrain is also extending its wastewater network, with four projects under way to install sewerage networks at Sanad, East Riffa, Jidali and Ekr.
Wastewater projects in Bahrain have traditionally been financed by the state or through loans on lenient terms from development agencies based in the Gulf. But the government is increasingly looking to the private sector. It has requested proposals for the planned 150,000-cm/d sewage treatment plant at Al-Dur on the island of Muharraq. As well as building the facility, the successful developer will operate and manage the plant for at least 25 years.
The facility is expected to be used as a template for future projects. A consultancy team working on the Muharraq plant has also been asked to draw up a privatisation programme, due to be submitted by the end of the year. The team includes UK companies HSBC as financial adviser, consulting engineer Fichtner and law firm Norton Rose as legal adviser.