7. Feed sufficient liquid sodium hypochlorite solution, according to label directions, to achieve a free chlorine
residual of 25-50 ppm.
8. The use of a bio-dispersant is recommended to aid in the penetration, removal, and dispersion of biofilms.
9. Have an effective antifoam product readily available to add when using bio-dispersant or quat-based biocide
as part of the procedure. Both can produce foam that builds up and can exit the tower or cause other
problems.
10. Maintain a minimum of 10 ppm free chlorine residual for 24 hours. Add more biocide as needed to maintain
this free chlorine residual.
11. Monitor the system pH regularly. If the pH of the system is higher than 8.4, it should be reduced to 8.4) reduce the effectiveness of chlorine-based halogens.
12. At the end of the procedure, but before the fans are turned on, bleed the system heavily to help flush loosened
biological matter and other debris from the system. Also, flush system low points.
13. Refill the system and repeat steps one through 10.
14. When no biofilm is present, mechanically clean the tower fill, tower supports, cell partitions, and sump. Wear