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3D TRASAR
5500 - Installation & Operation Manual
38. When using 3D TRASAR Bio-Control, what halogen residuals can be expected?
The amount of halogen residual measured in the system water will depend on microbial activity in
the system. This in turn can depend upon factors such as ambient temperature, process leaks,
system design etc.
The highest level of halogen (total residual) observed in a cooling tower under 3D TRASAR Bio-
Control is 0.8 ppm. The lowest level observed is 0.0 (below detection limit of Hach DPD test).
During periods of moderate demand, total halogen residuals in a cooling tower can be expected to
be 0.1 - 0.4 ppm TRH. ORP levels at which control is maintained depends upon the oxidizing
biocide used (STA-BR-EX: 150-340 mV, Bleach or Actibrom: 270-340mV).
Variation in ORP (mV) and total halogen levels in a cooling tower under 3D TRASAR
Bio-Control.
In this graph
, STA-BR-EX was the oxidizing biocide. On-line halogen was monitored with
a Hach Cl-17. Using 3D TRASAR Bio-Control, ORP varied between 180 - 320 mV and
the halogen levels varied between 0.0 - 0.4 ppm (total). 3D TRASAR Bio-Control adjusts
halogen dosage based on demand. There is thus seasonal and diurnal variations in the
concentration.
