The plant will have capacity of 18,500 cubic metres a day. The deadline for bids is the end of April.

Rakeen had originally planned the plant on an engineering, procurement and construction basis but has converted it to a concession contract.

Al-Marjan island is the first man-made island to be developed in Ras al-Khaimah. It is located 27 kilometres southwest of Ras al-Khaimah town centre and the cluster of five coral-shaped islands covers an area of 2.7 million square metres.

The development will include waterfront homes, floating villas, hotels, resorts, sports facilities and commercial areas. The project is worth an estimated $1.8bn.