Recycling process water in cooling

In the 1970s, direct input of phenol-bearing process water to cooling towers was tested. The towers were turned into immense trickling filters , with biological purification accepted in the towers provided there was considerable maintenance. For example, 400 to 

The cost of maintenance and the reliability of biological purification now prompt operators to carry out biological purification on process water first, following up with a tertiary treatment. 

The choice of purification tecliniques depends on local conditions, often there is much to be gained by using existing equipment. 

Two French refineries have successfully applied two quite different schemes. In both cases, deballasting and desalting water was excluded (see Chapter 6). 

The Shell refinery in Pauillac formerly used to need 90 m h of water from the Gironde river to provide make up for the open recirculating coaling system. Recycling process WW enabled them to reduce the final discharge of effluents from 200 m h to 50 with 

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