Desalination Plant of the Year
Atacama Desalination Plant, Chile
What is it?
A 38,880m3/d SWRO plant serving more than 210,000 people in the Copiapó region in the Atacama, the world’s driest non-polar desert. It is Chile’s largest desalination plant designed solely for drinking water production to date.
Who is involved?
The plant was delivered on a design-build-operate basis by a team comprising GS Inima (65%) and Claro Vicuña Valenzuela (35%) and funded entirely by the Chilean state through sanitation company Empresa Concesionaria de Servicios Sanitarios. Water is supplied to local utility Nueva Atacama. Energy recovery devices were supplied by ERI and process pumps by Flowserve while membranes came from LG Chem (RO) and Inge (UF).
What makes it special?
The innovative use of an in-line process design and an adaptable intake setup that maximises seawater pump efficiency means the plant operates at an energy performance level that can be as low as the 2.63kWh/m3 achieved during the performance test, an astonishing new benchmark for the industry.
With a sensitive local environment, and a rocky cliff seafront location, the project had major challenges just to connect to the sea. The use of microtunnelling minimised the impact on an environmentally sensitive area and allowed the creation of a subsea intake that ensured high quality raw water, while the use of a booster pump to iron out pressure differences allowed an even flow in a marine area that can see rapidly shifting water quality and salinity levels.
The construction was delivered on a breakneck 30-month schedule, with construction shrugging off the impact of the pandemic to deliver a desperately needed facility in an area that is in the grip of a critical ongoing water crisis.
Distinction
Rabigh 3 IWP, Saudi Arabia
What is it?
A $700 million, 600,000m3/d privately owned SWRO desalination plant on Saudi Arabia’s Red Sea coast, supplying water to the cities of Jeddah and Mecca.
Who is involved?
The project was delivered on a 25-year build-own-operate basis by a team comprising ACWA Power (70%) and Saudi Brothers (30%) for the client, the Saudi Water Partnership Company. It is operated by ACWA subsidiary Nomac. The EPC Contractor consisted of a Consortium formed by Abengoa, responsible for the desalination system; Sidem, in charge of the pre- and post-treatment systems; and SEPCO III, who managed the construction stage. Equipment was supplied by ERI (energy recovery) and ROPV (pressure vessels), Torishima and Flowserve (pumps) among others, while Toray supplied RO membranes.
What makes it special?
The plant stakes a strong claim as the most energy efficient ever to be built, accounting for its size, location and source water quality. The use of a managed pressure centre approach to RO allows for a more efficient use of fewer, larger and more efficient high-pressure pumps. Alongside other innovations, this means the plant operates at an average power consumption rate of around 3.1kWh/m3, smashing the 3.5kWh/m3 benchmark set by the client and outlining a future for energy efficiency on the largest scale.
Despite the ongoing phasing out of national subsidies for electricity, doubling the price for developers, the plant delivers water based on a levelised tariff of just $0.53/m3, the lowest ever seen to date in an operating desalination plant. This means huge savings for the client and supports the Kingdom’s huge water investment ambitions in even the most price-conscious of financial environments.
The design and management of the plant offers a masterclass in the intersection of desalination and big data. ACWA’s in-house cloud-based performance modelling software allows for a tailor-made design and an infinitely detailed operating approach that means the plants availability runs well above market benchmarks, while the wealth of data generated means innovations can be made such as efficiencies in dosing that has already reduced chemicals significantly.