H2S, carbon and air input needed

I have mild H2S in my water. Constant in both hot and cold. I originally bought an all in one iron softener with KDF, but you guys talked me out of the KDF. The softener is working great, but I do need to do something about the H2S.

I'm having trouble making the decision as to activated versus catalytic carbon, and whether or not I should get an air injection valve.

Obviously the catalytic carbon and the air injection are more expensive. Does the extra money get you significantly longer life or better performance?

I am also concerned with pressure drop with another tank, are the carbon tank service flow numbers based on the assumption of treating really nasty water, or based on flow impedance?

I would go with GAC and a Fleck valve of your budget choice.

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Originally Posted by Tom Sawyer

I would go with GAC and a Fleck valve of your budget choice.

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Tom what is a GAC???? Thx

P.S I have a similar situation

Carbon (Granular Activated Carboc) service flow rates are based on removal of multiple chemicals including VOC THMs Chlorine, etc. The Carbon will flow much higher than the service flows but lower removal rates will occur. Chlorine removal rates will usually remain very high even at higher flow rates. For H2S, I would recommend a catalytic GAC, but many people use standard GAC with great success. You should not notice a flow reduction if you install a good quality and properly sized GAC. I would recommend at least a 1.5 cu. ft. or parger unit.

Wiki says : Granulated Activated carbon, also called activated charcoal, activated coal, or carbo activatus, is a form of carbon processed to be riddled with small, low-volume pores that increase the surface area available for adsorption or chemical reactions.[1] Activated is sometimes substituted with active.

Due to its high degree of microporosity, just one gram of activated carbon has a surface area in excess of 500 m2, as determined by adsorption isotherms of carbon dioxide gas at room or 0.0 °C temperature. An activation level sufficient for useful application may be attained solely from high surface area; however, further chemical treatment often enhances adsorption properties.

Ill have to add that bit of information to my training seminars. I rarely go into it that technically during my training seminars, but that just sounds good!

Anyone attending the Pentair University in October? Word has it we may get to play with the EDI unit.

Seems the flow rate for carbon of either type is only about 2gpm/ft^3, so ~4gpm for a 2cf tank. What kind of service flow can I really get through a 2cf tank without a noticeable pressure drop? They say flows of 2-3x the specified service flow are possible. I plan to install this after my 1.5cf softener, so it's not going to be seeing any iron, just H2S.

Price for regular GAC looks to be ballpark about $100cf, catalytic about $200cf. Does the catalytic pencil out and last twice as long or subjectively work twice as well? Realistically, what should I expect for rebed frequency? I'm thinking maybe 3-4 years?

Catalytic carbon on paper is better than standard GAC for H2S. The flow rate of a 2 cu. ft. with a 7000 valve will peak in the 17-20 GPM range. Service flows are as you stated, much lower. Take a good look at your house and try to determine the actual peak usage, not a theoretical peak. Do you regularly run the laundry, dishwasher, 2 shoers, flush toilets, and use faucets all at the same time? Not likely, so a 2 Cu. Ft. GAC should definetly meet your needs.

What level of iron do you have? You may find a much better solution for H2S and iron. Can you post a recent water test? If you own a well, a proper test is relatively cheap and should be done every year or so.

I only have about 1ppm iron and 6-7 grains hardness.

I also considered a Filox tank, but thought with the low level iron being taken out by thr softener, that carbon might offer an overall better water taste and smell. I also have concerns about ORP with Filox. Does catalytic carbon have the same needs?

Ideally I will get a tank and valve that will work for either in case I want to switch things around later.

I ordered a 2cf Centaur unit with a 7000SXT head on it. I'll give an update in a few weeks once I've got it running.

Good choice and good luck

I got the equipment today. I filled the tank with the carbon and water, I'll let it soak till the weekend. That was a dusty job, and that 7000 valve is HUGE!

The instructions recommend chlorinating the well and all plumbing. Do you guys think that is a good idea, I hate to do it unnecessarily but will if it's the right way to make sure this is started up correctly.

I would. It's not a bad idea to flush any bacteria from the whole system before you put the carbon filter onliune. Bacteria grow profusely in carbon media.

Does the carbon system itself need to be disinfected? I was assuming it would be wise to put the carbon and softener on bypass when doing this.

Carbon will stop any chlorine from going through so sanitizing can be difficult if not impossisble. If bacteria becomes a concern, changing the carbon regulalry will help minimize this issue. The systems should be bypassed during sanitization, but the softener can be sanitized seperately by adding a small amount of bleach to the brine tank and regenerating the system. This should be done rarely as chlorine will damage resin over time. A single sanitization will not affect it in any way that you would notice.

Starting up Centaur carbon, soaking it for a few days is highly advised, as well as running it through multiple backwash/fast rinse cycles prior to running it to your house.

Congrats, you got yourself a great system.