the multi-stage flash distillation technology which uses steam from thermal power plants as an energy source. Their water production thus is proportional to electricity production and reaches a peak during the summer when electricity production is highest to power air conditioning. The recharge scheme is currently under construction and is due to be completed by 2013. Sanitation Approximately 550,000 cubic metres of wastewater is generated in Abu Dhabi every day and treated in 20 wastewater treatment plants. Almost all of the wastewater is being reused to irrigate green spaces. While most wastewater treatment plants are publicly owned and operated, four large new plants have been built by joint ventures under build-own operate transfer (BOOT) arrangements. One such contract for two plants was awarded in 2008, one in Abu Dhabi itself with a capacity of 300,000 cubic meter per day and one in Al Ain with a capacity of 130,000 cubic meter per day. Contracts for two other plants were awarded to Biwater under a similar structure. A Strategic Tunnel Enhancement Programme (STEP) is to be implemented between 2008 and 2014 to establish a tunnel that will comprise 40 kilometres of deep sewerage tunnel and two new large pumping stations to relieve Abu Dhabi Island. In Masdar City green spaces and agriculture near the city are to be irrigated with grey water and reclaimed water. Water use About half of the annual water production from all sources is used for irrigation of green spaces, as well as in agriculture. The other half is used for domestic uses. Freshwater use per capita is about 650 liters per day, including water supplied for the irrigation of green spaces. As of 2009, in Al Ain "due to constraints on both the transmission and distribution networks, up to 45% of customers (were) on a restricted (intermittent) supply". History Abu Dhabi has witnessed an explosion of wealth and population since its independence in 1971 and the oil boom of 1973. Before, groundwater was the only source of water supply. It was very scarce, since there is little recharge and most of the aquifers are highly saline. It was only through seawater desalination that the growth of Abu Dhabi became possible. Seawater desalination used thermal technologies that couple desalination with power production. Water was provided free of charge. The plants were initially owned and operated by the government through the Water and Electricity Department, and financing was