Dear All

 
We are working in a project were potable water supply has very low concentrations of Cl- (about 15 ppm, 20 times below the maximum level defined in credit language).

However, cooling tower make-up water will include the addition of chlorine as a biocide treatment (which is, by far, the most common option for biocide). The addition of chlorine to the potable water will likely lead to concentration levels of Cl- in make-up water very close to the maximum level defined in credit language (thus leading to 1 concentration cycle and becoming the limiting factor). The questions are the following:

  1. For the purposes of credit calculation, water analysis shall be made in potable water as referred in credit language? Or in make-up water, after the addition of chlorine?
  2. If water analysis is to be made in make-up water, which strategies can be adopted to increase the concentration cycles beyond the maximum level defined for Cl- when chlorine is used as biocide?

Best regards,