Brine and trucks: Qala’s concerns on reactivation of Hondoq desalination plant

The proposed reactivation of the Hondoq desalination plant will result in the hourly discharge of 500m3 of brine, which will be disposed of in deep water, 260 metres from the plant and have a negative impact on protected sea grasses, which are highly sensitive to changes in water salinity.

However, while the Environment and Resources Authority is considering the project “favourably” if adequate measures contemplated in ecological studies are fully implemented, the Qala Council is calling for more comprehensive studies to ensure the protection of the sea grasses, which keep the ecology of the beach in balance.

The plant will be extracting water from the sea, desalinating it and discharging the residual brine water back into the marine environment through a submerged 260-metre-tunnel outfall.

The AA report indicates that the brine will be released in deeper waters through a tunnel, which will be directed in a way that avoids negative impacts on Posidonia oceanica, which is very sensitive to changes in water temperature and salinity.

The discharge point is devoid of sea grasses and dominated by “bare sand and mud”. The brine is expected to sink onto the seabed.

The Environment and Resources Authority had called for an  “appropriate assessment”(AA) report to assess the impact of the reactivated plant on surrounding protected natural areas.

But the council has now called for a full Environment Impact Assessment to assess the wider impacts of the project.

Five to seven trucks per hour

One of the concerns of the council revolves on the  need for the “construction” or “resurfacing”of the main access roads to the plant mentioned in the report . The council has recently resurfaced the road leading to the plant.

“Does this mean that new roads are required and where, and has consideration been taken of the fact that the road has recently been resurfaced by the council?”

The council also asked for more information on the route , which will be taken by the five to seven trucks, which will be passing every hour to undertake works on the new plant.

On its part the Environment and Resources Authority has called for proper synergy in the management of traffic during the construction phase “to pre-empt undue difficulties in the continued use of existing access routes and  avoid “pressures for new or altered access routes”.

The council has also called for enforceable guarantees with regards to noise abatement measures.

Plant to reduce ground water pressures

The seawater reverse osmosis (SWRO) plant will be producing 9,000m3/day of potable water. The process entails the extraction of seawater from deep shore wells sunk in Coralline Limestone, to eventually settle in a buffer tank. For this project, six new seawater wells will be constructed.

Following the separation of brine from potable water, the brine will be discharged at sea at low pressure through a horizontal directional drilled outfall, submerged at sea, 260m away from the coast. The potable water will be piped to the Ta’ Cenc reservoirs across the island of Gozo.

80% of Gozo’s supply of water is highly reliant on groundwater abstraction. The appropriate assessment describes this source as “a scarce and somewhat contaminated natural resource on the Maltese islands”. The AA warns that  Gozo’s total dependence on groundwater extraction would contribute towards the gradual depletion of the island’s freshwater resource.

The remaining 20% of Gozo’s water supply is dependent on Cirkewwa’s reverse osmosis plant and the submarine pipeline that connects the two islands. The AA warns that any failures in the supply will not be able to cater for the provision of water used for human consumption on the island of Gozo.

ERA has concluded that the project can be “considered favourably” if all the mitigation measures proposed in the AA are implemented.