Coll The Coll Magazine

Article by R M (2000)

Island News

New Water

At 4pm, and without ceremony on the 7th of February 2000 the new Coll water treatment works was put into service, supplying Arinagour Village with crystal clear, top of the range, E.U. compliant water. The event marked the culmination of nine months of work by civil engineering contractors, MacFadyen's of Campbeltown, MacKinnon (builders) of Tiree, Oban Electrical Services and PCI-Leopold Membranes of Southampton who designed, built and supplied the water treatment plant.

The project was initiated and majorly funded by the West of Scotland Water Authority in compliance with an E.U. directive to bring the water quality of isolated communities like Coll, up to E.U. standards. The cost of the project (have a seat!) amounted to 750,000 of which 120,000 was E.U. grant aided.

The treatment plant itself consists of an array of nine modules, each of tube shape (4m length x 200mm diametre) containing 72 smaller tubes connected in series. Raw water from the supply loch is pumped through these tubes at high pressure (8 Bar) and filtered water permeates through a plastic membrane which coats the inside of these tubes. This reverse osmotic action results in crystal clear, almost distilled, water. The filtered water is then chlorinated (because of its purity, less chlorine has to be used to disinfect it) and passed through a tank containing limestone chippings which changes the pH from acidic to alkaline. Finally it is pumped up to the storage tanks (on top of the hill behind the works), thereby providing sufficient pressure to directly feed the village network. The storage capacity of these tanks (one new) amounts to about 80 cubic metres or 80,000 litres in total.

The operation of the plant is controlled by a programmable logic computer which monitors the quality and quantity of treated water, having the ability to shut the plant down and alarm out to W.O.S.W. Glasgow Control Centre if any problems arise that might compromise its quality. It is designed to produce about 2 cubic metres of treated water per hour from 3 cubic metres of raw loch water. In the off season the plant runs about 12 hours per day to satisfy village demand but will, I think, have to run flat out in high summer to do the same. The works' part-time operator might well have to ask for water economy during this time - well, there has to be a down side to it all! - Time will tell!

Change is a difficult thing and for those who might still long for the good old days when village drinking water was peaty coloured with "bits" in it, I'm sure the musicians amongst us might come up with a suitable lament to mourn its passing - but I'm also sure, for most of us, that would be hard to swallow!!

Coll Magazine - Article by R M

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2007 The Coll Magazine