SWIMMING POOLS REASSURED ABOUT ALUMINIUM

Pool operators anxious about the implications of the drinking water contaminated with aluminium in Camelford (Lowesmoor) can be reassured - says the independent Pool Water Treatment Advisory Group (PWTAG). The use of aluminium coagulants in swimming pool water treatment should never give rise to the levels found in Camelford drinking water.

But it is important that certain guidelines from PWTAG's new book, Swimming Pool Water (details below) are followed.

Hand dosing coagulant, or placing it in the strainer box, is not acceptable in a large public pool - and in any case never when people are in the pool.

Dosing should be by dosing pump - preferably continuous, small amounts (minimum 0.05mg/l as aluminium), adjusted to the changing bathing load.

The traditional UK dose of about 20mg/l after every backwash gives inferior water and more chance of bather discomfort.

Aluminium-based coagulants work best at pH values between 6.5 and 7.2. Above 7.2, alum may get into the pool; if there is doubt here, the pool water should be tested for aluminium residual.

Coagulant dosing points should be well away from chlorine sampling points and from other dosing points.

PWTAG Chairman, Andy Elphick, is concerned that coagualation is done properly, as an aid to effective filtration. 'It would be a shame if the renewed publicity about the Camelford incident made pool operators worry about coagulation with aluminium compounds. As long as they follow the sort of guidelines in our book, they needn't worry.'

SWIMMING POOL WATER Treatment & Quality Standards (ISBN 0 9517007 66) is £35 (UK), £45 (Overseas) including post and packing. It is 144 pages and distributed by Greenhouse Publishing (tel: +44 (0)1379 890721 or fax: +44 (0)1379 898244). Bulk supplies (in boxes of 33) are available from PWTAG's secretary.