Chlorine Adsorption and Granular Activated Carbon (GAC)

good response Kevinm.

to get rid of the chlorine, you can try sodium bisulfate or other reducing agents before the GAC filters, making sure you don't overdose it and mix it well.

If you are dealing with city water, there are some reliable chlorine probes out there. You can use the probe reading, a flowmeter and a metering pump to dose the exact amount of SBS.

If you add a reducing agent, the mixing and contact time is important (for SBS only need 15 to 30 seconds).

If you overdose, and then add ozone, you will need to satisfy the demand before you'll see any ozone residual.

hope this helps.

GA Sardman. Another option may be to drill a well to supply water instead of using city water for process. If OP is in the food business he may find this online book of interest, industrial food text .

If OP needs further assistance let me know in this thread and I can give him/her a site that will get in touch with me.

Thanks for the help. There is never an easy answer... I was hoping to pre-treat the water to remove the polportho-phosphate.

I was thinking of conventional treatment (lime, FeSO4,Coagulation / Sedimentation) and using a Polymer to brake the PP bond?

The end effluent must be potable water.

I have not been specifically asked to treat PP on a large scale. I would also assume that the PP is approved by NSF and is suitable for potable water so its presence should not be an issue with potable water.

My understanding of Lime treatment and coagulation is retention times may be high and on the order of several days for PP removal. The methods mentioned work well in sewage treatment but I am dubious about its use in potable water. Polyphosphate will encourage bacteria to grow and its accumulation could create other issues. When PP is used there is often a green algae formation in storage tanks for example. I don't know what flow rates you require as treated water but you should seriously look at de-ionization (DI) or reverse osmosis as Best available Technology (BAT). If you use DI you can run parallel banks of smaller filters as opposed to single large flow filters. Smaller filters are cheaper to maintain, use chemicals more efficiently and provide cost effective redundancy. Storage would be required and post disinfection with UV.

As an aside, I have used AC effectively with PP as a pretreatment. We were not trying to remove chlorine but creating biologically activated carbon (BAC) to remove exotic organic contaminants. It is still working today as far as I know. BAC is commonly used in this manner and is often BAT. I think there may be better AC that will remove chlorine and not be severely interfered with by PP. Talk to manufacturers and not suppliers as it is these companies that employ the experts.

Water guys have lots of acronyms just not as many as computer geeks and medical people...yet.

If they want holy water, tell them to boil the hell out of it.

Thanks Kevin,

Would you know what we could look for in the water that could be blocking the waters ability to absorb CO2?

We are trying to saturate the water to 4.5 Volumes of CO2. To do this we are using about 30% more CO2. The product is very unstable and the CO2 is released. (the product goes flat).

We do have the option to use an alterative water source but that becomes very expensive.

This question can be complex as CO2 uptake is affected by dissolved solids, alkalinity, Henrys Law, Temperature, pH, and pressure.

Temperature and pressure come to mind first as effecting causes of CO2 uptake in water. The pH may also be a factor. If you made your water colder more CO2 will dissolve. There are temperature/CO2 charts that you may want to study. Is it possible to get higher pressure to hold the CO2 (enclosed and sealed container). You may want to send William Vander Wilp, a good water chemist , at william@mwater.ca (www.mwater.ca). *(Tell him Kevin sent you). I just don't have the data at my fingertips. I can only help where I can.

Thanks again,

I should have given more info... the temp at the point of CO2 injection (pressure vessel) is 36F to 38F; the pH is 6.8 to 7.2; the TDS is 50 and the AlK is 15.

There is a lot of water chemistry at play...

Temperature should be cold enough to let you add a lot of CO2. After you add CO2 (4%VOL), I expect the pH to go down significantly. Pressure should be the main parameter.

when you said that the water "goes flat", where does it happen? if you have a pressurized vessel, you may want to make sure the pressure si what is supposed to be.

Something else you may want to check are the velocities in the pipes: if you have very high velocities, pumps, bends and sudden expansions, you may be goving the dissolved CO2 a reason to tey to get out.

Before the city began using this PP in the water, we could carbonate the water to 4.5 vol. @ set temp using 60PSI in the carbonator. After the carbonation process the water would be bottled (under pressure). The product was very stable, even after being exposed to atmosphere. (Bottle opened). Now to get the same CO2 Vol we need 80 plus PSI. and the product goes flat very fast when opened.

We are in the process of have the water tested from the city's source through the city's process to our incoming water. Hopefully something will show up…

Thanks for the suggestions.

This is another book dealing with carbonation and soda drinks if it applies. Your water looks like mountain water. My guess is the PP is for corrosive control and to prevent possible lead release from plumbing... based on these test results. Good for beer making. Has anyone tried adding dry ice to carbonate water. It may be explosively dangerous though if confined. Just brain-storming and not yet serious but the transfer of CO2 would be high if introduced to water. Don't try it without more research.