Removing hydrogen sulfide from well water

I am trying to start back up my aquarium fish breeding business. One obstacle is the well water I have to use. Raw it is full of iron sulfates and hydrogen sulfide, and other noxious chemicals. If the raw well water is left to sit it goes from a being a thick green to being red orange and red orange mud settles onto the bottom. Once I run it through water a softener system it comes out clear and very soft but still full of hydrogen sulfide and almost totally anoxic. I need to be able to remove the H2S and add oxygen. I have thought of using H2O2 to add oxygen but will this also remove the H2S? any ideas that would allow me to use the water immediately as it come from the ground? Or even treat it in vats for later use.

Your best bet might be to draw out a large volume of conditioned water and let it age in open vats with some heavy circulation for a week or so. This would allow O2 to diffuse in and H2S to diffuse out.

I'm not sure how suitable your water will be for fish rearing, though.

Yikes. I don't envy you. Do you drink that stuff?

Peroxide will oxidize the hydrogen sulfide. The sulfur will still be in the water, but it won't be toxic. Andrew's aeration suggestion will work too, and be less expensive, but will take longer. Peroxide will work in about 15-45 minutes.

Both suggestions are good. Aeration should drive off most of the H2S and add Oxygen. Peroxide will oxidize the H2S as well as other organics.
Plain old bleach works really well. The H2S will be oxidized and the iron will settle out. You can pour off the clear supernate and add chlorine remover.
Water companies will try and push softeners. That's great for eliminating stains in your toilet and odors in your water but will not help your fish.

Any way you do it, I wouldn't add water containing large amounts of peroxide to my tank containing fish eggs or fry. It seems like it would also interrupt cycling in your tanks too--but that's more of an educated guess.

The peroxide breaks down very quickly, though; by the time the water goes into your tank there should be no H2O2 left.

Cl2 will do it.but there are issues here.
You say well water
is it from under a swamp? this maybe a food by-product produced from
the h2s.it may be from the break down of sulfites if so it may be a flammable gas let it stand in a open vat for some time
Hepatic gas can be sent to a solid with a chemical reaction by adding Chlorine.
do a google on sand filter to remove the sludge-(as in yellow stuff).
ok now you have a large tank of h20 with a high yield of sulfate in it.
do a water test.
to see were you stand.
do a google again and build a still.
clean your h20 if its liquid rock with the sand/carbon/lime filter.
if it was my water i wouldnt bother. just have some drop shipped for my time and $
or start a distillery for corn liquor you are 80% on your way minus the red tape and taxes.
but what do i know im just a man trying to keep my bait alive.

Edited by CATfishTONY, 20 June 2009 - 01:44 AM.

Potassium Permanganate (KMnO4) would also do the trick I just realized. But then you'd have to deal with the purple water.

Peroxide may be dangerous to very small fry, but it's fine for adult fish. After a good deal of research I started using it for spot removal of algae, and it works great. The chemical breakdown is caused by energy input from light, so it doesn't break down much in the filter and won't harm the cycle, and it's removed quickly before it can harm fish.

Peroxide may be dangerous to very small fry, but it's fine for adult fish. After a good deal of research I started using it for spot removal of algae, and it works great. The chemical breakdown is caused by energy input from light, so it doesn't break down much in the filter and won't harm the cycle, and it's removed quickly before it can harm fish.

Aeration by dropping the water via gravity through plastic media will remove noxious gases and add oxygen. (Packed Column) However this is preferably done outdoors or in a large ventilated building or you will have an odor problem inside!


I guess it depends on how much water you need.


Iron filters, Sand filters, filters using greensand, or potassium permanganate are an alternative to remove the iron. If you don't need a lot of water removing the above via aeration and simaltaneously adding oxygen, and then allowing the iron to settle out would be the most economical.

Here I drop well water through plastic media in five gallon buckets to blow off noxious gases and add oxygen. Note the iron build up on all surfaces. I pretty much live with the iron in my outdoor trout pond although once the well has run a while (I don't start it up until Spring) it seems settling in the trout pond, and iron bacteria seem to reduce the iron level substantially. I'm convinced the prolific Chara in the pond is used as a media surface for the iron bacteria. Chara being a form of algae may also use some of the iron. Iron coming in about 2.5 mg/l. Iron in the pond itself goes down to 0.4 mg/l after a couple of months.

A really simple solution would be to have an outdoor pond that you periodically run well water into and due to it's large enough area takes care of aeration and iron settling.

You're my hero. You should send that picture to Jeff Foxworthy

If you are trying to keep cost and risks (associated with chemicals), then I would follow Az9's suggestion with a minor addition. The first stage would be as Az9 presents and the second would be a fairly large tank receiving as much supplemental aeration as you can afford. We use a similar exchange columns to aerate well water going into raceways, Initial dissolved oxygen is about 0.5 mg / L, but after a 5 foot drop through a 6 inch pipe similar in function to the buckets Az9 uses the dissolved content approaches 7 mg / L. Most of the hydrogen sulfide and CO2 (we are concerned with latter the most) coming from well diffuses into the atmosphere. The second stage polishes, allowing solids to precipitate helping to further increase the intervals between servicing plumbing / valves.


Also, the bucket system as shown is as counter current exchange where water with very different dissolved gas concentrations fall down through an area with air going the opposite direction. The air a the bottom of the tube has very low concentrations of dissolved gases like H2S and CO2 but high O2. As the water perculates down, the air rises up. The rising air can strip gases from the water even near the top because that is where the water has the highest dissolved gas concentration (except oxygen).


Keep top and bottom of tube open!

You're my hero. You should send that picture to Jeff Foxworthy

Hey it does the job and there is no additional power requirement as gravity does the job.

BTW I used to have just a 10 inch PVC pipe for a packed column and was told by a Canadian prof that the buckets would work even better. He was right. Being open segments vs. a closed pipe I get a little more oxygen saturation.

And Centrarchid is spot on as usual. Counter current air would work even better, however in my case I try to keep my power requirements as low as possible and doing that would require more power. I also run mine into a pond where upon entry it gets gravity dropped once more and the pond is not as crucial as a raceway.

Edited by az9, 04 July 2009 - 12:37 PM.

Az9,

Your system does employ air flow. Cover your top bucket to stop air from flowing and it will greatly reduce performance of your device. I think what happens with your setup is that it chills water causing it to fall when air temperature is warmer than water. When air is cooler, counter current mode comes into play as water heats air causing it to rise. If temperatures nearly same, then increasing humidity should cause air to rise also.

Az9,

Your system does employ air flow. Cover your top bucket to stop air from flowing and it will greatly reduce performance of your device. I think what happens with your setup is that it chills water causing it to fall when air temperature is warmer than water. When air is cooler, counter current mode comes into play as water heats air causing it to rise. If temperatures nearly same, then increasing humidity should cause air to rise also.

Very Interesting!