Sant Antnin water treatment plant to re-open in 2020

The Sant Antnin water treatment plant in Marsaskala, constructed in 1982 to provide farmers with irrigation water, is destined to outlive the nearby waste recycling plant which the government will relocate to Maghtab.

The plant, which ceased operations, is expected to re-open in 2020 after being retrofitted with environmentally-friendly measures that will stop the arrival of solid sewage to the plant.

While the new investment in the plant will increase the sewage treatment capacity in the south of Malta by 17,000 cubic metres a day, it will no longer be providing farmers with irrigation water as farmers will be getting high quality ‘new water’ produced from the polishing plant at Ta’ Barkat in Xghajra.

The plant represented the first efforts to recycle sewage water and even fulfilled an educational role by hosting school visits to instil awareness on water conservation issues but farmers were always sceptical about the quality of this water which was deemed too salty. Residents also complained of odour problems.

Moreover the availability of ‘new water’ from sewage treatment plants constructed in the past years has now rendered the plant obsolete in providing this resource.

According to the Water Services Corporation (WSC), the new water exceeds European Union standards and can even be used as class-A secondary water – on crops that are eaten raw. The Water Services Corporation is also in the process of developing a network of dispensers from which farmers in the south of Malta will be able to collect the new water.

Yet the Sant Antnin plant is now destined to outlive its original purpose and will now serve to boost the WSC sewage handling capacity. A tender for a partial retrofit of the Sant Antnin Wastewater Treatment plant was awarded in December 2018 for the value of €4.25 million.

The plant is expected to be put in service by the first quarter of 2020, employing a more energy efficient and environmental-friendly treatment process. The retrofitted plant will increase the southern region’s catchment treatment capacity by 17,000 cubic metres per day.

The Sant Antnin Wastewater Treatment plant and the Ta’ Barkat Plant will be interconnected to ensure greater efficiency and operational flexibility.

As built in the 1980s, the Sant Antnin plant was receiving raw sewage for treatment. The treatment methodology used to work mainly through the blowing of air in open tanks. This was a very energy-intensive and inefficient process, both in terms of resources used and treatment capacity.

With the new investment, instead of receiving raw sewage directly from the sewer, the Sant Antnin plant will now start receiving sewage from the Ta’ Barkat plant in Xghajra, which will be interconnected to Sant Antnin through underground tunnel pipework. This will impede the arrival of solids to Sant Antnin, as the sewage would have already gone through core and fine screens. In this way the sewage will arrive in liquid form already filtered to 3mm. This is expected to reduce odour problems.

The treated wastewater at the retrofitted Sant Antnin plant will still be discharged through the outfall at Ta’ Barkat. But further polishing of the effluent for reuse in the future is not excluded.

Unfortunately the works had one unforeseen impact on national waste agency Wasteserv, which was previously serviced with water from the plant and cannot do so now due to the temporary closure of the plant. In view of this Wasteserv has issued a call for the supply of 5,000 cubic metres of water from private suppliers – with private bowsers which extract groundwater not being excluded.

Secondary water is a vital component in anaerobic digestion through which organic waste is transformed in to methane.

“This is the first call of its kind since WasteServ has been informed by the Water Services Corporation that the latter will not be in a position to supply such water due to ongoing works being carried out,” Wasteserv chief executive Tonio Montebello told MaltaToday.