Why are you removing the ...
Published by Pat Stanford, General Manager
Why are you removing the chlorine? That will have an impact on how to best stage the processes. What else is in the water besides the chlorine? What concentration of chlorine are you trying to remove?
Carbon (at least some types) can act as a catalyst and convert chlorine to chloride without losing capacity. If the other compounds in the water will not impact the carbon, I would recommend the carbon first as it should provide the lowest operating cost and you will have to use less bisulfite.
If your downstream use needs to have minimal residual bisulfite, I would recommend putting the bisulfite in first and under dosing and then using the carbon as a posher to provide the cleanest effluent.
1 Comment
Hi, Pat
Residual chlorine will be less than 0.5 ppm.
will be used to feed an RO unit, drinking water application.
Coconut carbon will be used
Thanks
Published by Osama Hamad, Director at MDC Water
1 Comment
Are you sure the consultants have specified the carbon for chlorine removal? Often an RO unit will have a carbon unit installed to remove organic matter in the feed to slow the fouling rate of the membranes. If the carbon is designed for organic removal, then any extra Cl- removal is just an extra. Normally you want to remove the Cl- as close to the RO membranes as possible to minimize the sections of piping that can show biological growth.
If this was my project, I would probably do the carbon first and the bisulfite after, very close to the inlet of the HP pump and ensure the dosing pump is large enough to supply enough bisulfite to remove all of the Cl- and ignore any removal by the carbon.
Published by Pat Stanford, General Manager