Maltese island achieves water autonomy with SWRO innovation

As part of a €100m programme funded by the EU to improve water quality across Malta, the Gozo project involved a self-contained flexible source of high-quality drinking water.

One of 21 islands that make up the Maltese archipelago, the Mediterranean island of Gozo had historically depended on groundwater and a submarine pipeline sending water from Malta.

To handle peak season tourism demand, the government of Malta commissioned the €10m Hondoq plant, which uses seawater reverse osmosis (SWRO) to produce 9,000m3/day and fulfil the demand of over three million cubic metre per year.

Hondoq plant uses seawater reverse osmosis (SWRO)

Both Israeli companies, AST and ROTEC by WFI Group, combined to deliver the plant with optimal available technologies, in ration with the Israeli National Water Company, Mekorot.

The development is part of Maltese water services corporation’s (WSC) drive to become a ‘net zero impact utility’

The teams had to construct a new modern facility while working on the existing building, according to local preservation and restoration guidelines. The renovation was undertaken with a local architect and sub-contractor.

To accommodate Gozo island’s water needs, WSC has set out goals for its water supply to achieve drinking water autonomy with high efficiency and redundancy, enhance the quality of the drinking water and serve both the Gozo and Malta islands with a fresh and steady water supply.

WSC said the historic project is the first RO project in Gozo that will give autonomy to the island’s water production.

Boaz Shitzer, CEO of AST and ROTEC by WFI Group, said: “Malta’s Ministry of the Environment wanted to maintain the positioning of green desalination in the Hondoq Bay, with minimum impact on the environment. As a result, environmental protection measures were at the core of the project strategy and execution.”

Such environmental reduction measures included designing and building a high-density polyethylene (HDPE) pipe under the seabed using horizontal directional drilling. As a result, brine is discharged to the sea 350m from the plant, without affecting seawater vegetation and with minimal impact on the existing structure.

The plant incorporates a double-pass process design that can be implemented at a later stage to meet World Health Organization (WHO) and European standards for boron removal to levels beyond the local regulations. This will also allow more water reuse for agriculture, while minimising impact on the environment.

Shitzer added: “AST’s winning bid against several companies was based on low total water production cost, together with low energy consumption and near zero chemicals. WSC’s strategy included using off-peak hours production.” 

The plant operates at hours with low demand in Gozo and transfers water back to Malta

Furthermore, remote plant control is handled from WSC’s main operation centre in Shirakawa, Malta. The plant uses automation tools based on artificial intelligence (AI) software to enable updating, monitoring of performance and use of predictive maintenance trends to control the ageing performance of SWRO pumps and membranes.

WSC recently won an ‘Industrial Excellence Award 2022’ for the Gozo plant for development of the best engineered project by the Malta Engineering Excellence Awards.