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The System:
One open cell comfort-cooling tower manufactured by Marley located on the building roof four floors above the ground. The cooling tower system was part of a new construction package and had been in operation for one year with no bleed-off or chemical treatment.

The Problem:
The tower basin was extremely dirty. A visual examination indicated the start of sulfate-reducing bacteria (SRB). Follow-up testing was done using the Hach SRB BART test with positive results in 48 hours.

The Solution:
The tower system was flushed and drained. The SRB nodules were scraped and brushed. Nodules under the fill were knocked loose using a metal rod. The tower basin was vacuumed to remove all loose material. The system was refilled and both UKP-10 and UKL-06 were added at maximum dosages and circulated for 6 hours. The chemical treatment program consisting of HS-4230, C-366 and AA-315 was started. The C-366 was fed every Monday and the AA-315 was added every Thursday.

The Benefits:
Since the initial physical cleanout and addition of the UKP-10, SRB have not reappeared. Alternating C-366 and AA-315 on a weekly basis has been effective in controlling new growth.

Note: Do not add C-366 and AA-315 in the system at the same time. These two products are not compatible with each other.

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