Desalination Plant Needs Modifying After Contaminant Found

desalination plant signSt Mary’s new desalination plant will need a further £40,000 of modifications after ferrous oxide was found in the water feeding the facility.

Chief Technical Officer Neville Gardner told councillors at Tuesday’s General Purposes meeting that the chemical quickly forms rust when it’s exposed to air, which blocks the filtration system.

It doesn’t contaminate the finished water supply, which meets the current standards.

But it means the operators are having to replace the filters every two days at a cost of almost £300 each, to ensure the water keeps flowing.

The engineers who supplied the £480,000 system will place a filter in the building that held the old desalination system in an effort to solve the problem.

Cllr Richard McCarthy asked why this wasn’t flagged up when the new boreholes were drilled.

Neville explained that the material only gets into the water when it’s under load, which he couldn’t have predicted beforehand. But he admitted that one of the old wells in the same area had been heavily contaminated for years.

Council Chairman Amanda Martin suggested they get geological advice before drilling in the future.

The cost of the additional equipment will be partially covered by a £30,000 underspend on the original budget for the plant.

Neville also asked councillors to approve £10,000 of spending to improve the water main on Bryher.

Part of the system, which Neville referred to as “little more than a hosepipe”, is becoming exposed because of erosion, and could be damaged easily.

It’ll be replaced by new pipework.

Wider pipes will also be put in to feed several properties at Timmy’s Hill.

The money is likely to come from the £450,000 water reserves, meaning the work can start in the quieter winter season, although Neville said there’s a chance the Authority could get a grant from Defra for the upgrades.