Plans Submitted For Desalination Plant Fix

desalination plant signPlans for a new seawater intake for St Mary’s desalination plant have been submitted to the Marine Management Organisation.

The £500,000 water purification system, which was installed in 2013, has struggled to meet demand after the onshore boreholes that provide it with water became contaminated with iron pyrite.

That means the unit’s filters are getting blocked, costing up to £20,000 a month to replace.

Now the Council has asked to install a floating pump system, around 200m from the shore at Pelistry Bay, to take water from the open sea.

The intake will sit one metre below the water surface and will be connected to the desalination plant with a flexible plastic pipe.

It will also be marked with lights so is can be avoided by water users.

Last month, Tim Allsop from the islands’ Inshore Fisheries and Conservation Authority raised concerns about the location of the inlet, in a Marine Special Area of Conservation and close to a colony of rare sunset cup coral.

And he speculated that the large amounts of sediment there would also block the filters.

But the IFCA has now agreed to the plans, saying they’ve come to the conclusion that the water intake “won’t present an environmental problem.”

It’s thought the novel floating arrangement means the seabed will be left undisturbed.

There has also been no objections from Natural England and Scilly’s Wildlife Trust who were consulted on the plans.

In February’s General Purposes meeting, Senior Manager for Infrastructure Craig Dryden said the likely cost of the new seawater intake could be as high as £300,000.

And he said that would likely “wipe out” the £388,000 left in the water reserves.

Councillors raised water charges by 12% to help avoid that.

But the plans indicate that the cost of the new scheme is now likely to be a more modest £25,000.



3 Responses to Plans Submitted For Desalination Plant Fix

  1. Soutie July 31, 2015 at 12:10 pm

    ….you are forgetting the freight costs, Adam!

  2. Neptune July 31, 2015 at 11:57 am

    Oh dear oh dear oh dear, got it wrong again Mum. Crikey bit of a difference in the two estimates, the first too high the second very likely too low, never mind you will probably muddle through eventually. Sucking sea water straight from the ocean I cannot imagine anything could go wrong with that, or could it……

  3. Adam Morton, St.Martins July 31, 2015 at 11:13 am

    I have a saving suggestion Craig; 200m of say 63mm mdpe pipe £680.check valve £133.67 one 75″buoy with light £82.96 . So that when it gets blown away each winter, it won’t blow away the entire reserve fund with it!