Chlorine Dioxide Vs Bleach

[Rpsfinest]

At my current plant we treat our cooling tower basins with chlorine dioxide. During the shoulder months when the plant isn't being dispathced we still feed the clorine dioxide once a day untill we reach a level of 600 ORP. Unfortunetly when the plant is down and we have no need for make-up water, the HCL in the chlorine dioxide drives the tower pH down below our operating range. This causes us to dump a bag of soda ash into the basins to bring the pH back up. To get away from dumping the soda ash in the basin I was thinking of setting up the chlorine dioxide units to just feed Bleach. Will I get the same oxidizing potential as I do with the Chlorine dioxide? What risk do I run by continuing to treat the basins with a bag of soda ash? we are currently using about a bag per week per basin...

thanks folks

 

[bimr]

Bleach can be used as a disinfectant. It is probably more common to use bleach than chlorine dioxide. Chlorine dioxide has superior disinfecting properties, but bleach is less expensive and you can obtain satifactory results with bleach.

The risk that you take by adding soda ash is to increase the dissolved salt (TDS) concentration in the cooling tower. AS TDS increase, the water is more corrosive. This TDS is easily controlled by increasing the cooling tower blowdown.

 

[HEC]

Increasing the cooling tower blowdown increases the raw water inlet and the potential biofouling, potentially requiring more discinfectant! The incresed TDS is more likely to cause blocking of sprays i.e. shorter term problems. There are many alternatives for cooling tower treatments, talk to any of the water treatment companies locally for advice.

Mark Hutton