Residue Found in Softener Valve Head 1

[swall]

My plant recycles process water from a zinc phosphate line.We do a flocculation and settle procedure and run the resultant clear water through a bank of softeners followed by carbon filters. The softened and filtered water then gets run through our RO unit. During troubleshooting of a problem, we found calcium phosphate residue (flakes) in the valve bodies of the softeners. We also found the softener media bed granules to have been infiltrated with a similar substance (TBD) to the point where media had to be replaced. What could cause a problem like this? Is our treatment system just not sized for the amount of phosphates and hard water salts that are present?

 

[bimr]

Basically, the reactions do not go completion if you are precipitating the phosphate with lime. Consequently, “after-deposits” will form in the pipe line conveying the effluent, unless the effluent is partially neutralized with an acid to lower the pH. If the pH is lowered, you will eliminate the “after-deposits”.

 

[GarySCWSVI]

I agree with bimr. Softeners are not good at filtering particulate. Either adjust the pH or install a prefilter before the softener.

Gary Schreiber, CWS VI
The Purolite Co.