Cooling water systems treatment programmes

Industrial Cooling Water Systems Waters used for recirculating cooling systems can either be scaling or corrosive. Corrosive waters are treated with corrosion inhibitors which require monitoring for overall assessment of the treatment programme. 

Treatment of cooling water to combat corrosion, scale formation and biofouling can be achieved by a suitable programme. The cost may be high and for a modest cooling water system the cost may run into tens of thousands of pounds. 

Continuous ferrous sulphate addition has been used for many years to reduce water side corrosive attack of steam condenser tubes. It is usually applied to once through cooling water systems because of its low cost, to provide an iron-rich protective film on the tube surface. For recirculation systems other more expensive, corrosion inhibitors are generally employed. Two phases of the ferrous sulphate treatment programme may be recognised. The first phase involves the initial laying down of the protective film. The second phase involves the maintenance of the film, which would be otherwise destroyed by the shear effects of flow. 

Because of the widespread use of cooling water and the need to assess treatment programmes, monitors have been developed specifically for use in cooling water systems. Many of these devices are relatively simple and do not necessarily require the use of a mobile laboratory. Moore and Hays [1985] produced a survey of commercial fouling monitors that could be used in conjunction with cooling water and EPRI [1985] made a status survey of 18 biofouling detection monitoring devices. Chenoweth [1988] provides detailed information on ten such monitors. He observes that the choice of monitor depends on a number of questions, the answers to which will not only affect the cost but also the quality of the data obtained. 

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