Tunnel from Pembroke reverse osmosis to Ta’ Qali reservoir will secure water supply

An underground tunnel linking the reverse osmosis in Pembroke to the Ta’ Qali reservoir, aimed at improving Malta’s water quality and increasing security of supply, is to be constructed, the Water Services Corporation has announced.

The tunnel, the tender for which has just been issued, will also significantly better operational efficiency and positively affect environmental sustainability, the WSC said.

The project, which will be phased in three separate lots, all implemented at the same time, will see the building of a 9km long, 3km wide tunnel, capable of transferring 52,000m³ of desalinated water from Pembroke directly to the Ta’ Qali group of reservoirs through a 1.2m diameter pipeline. The desalinated water will there be blended with groundwater.

Ta' Qali reservoir

An intelligent control system will be used to monitor the blended water and control the dosing quantities at the Pembroke reverse osmosis, ensuring that less chemicals are needed to optimise the quality of potable water.

From Ta’ Qali, the water will go through a new gravity system which will supply the east areas of Malta, from Sliema down to Valletta. Another line will feed the Misrah Lewza reservoirs in San Gwann, using a separate pipleline.

WSC Richard Bilocca, calling the project “challenging”, said it would “revolutionise the way potable water if distributed and blended, resulting in improved quality across the Maltese islands”.

“The system will also reduce operational costs and increase security of supply, since most areas will be virtually fed without the use of pumps,” he said, adding that supply will be continuous even in the even of power failures.