Peroxide

Having well water with 10 ppm of sulfur, how much 35% peroxide do I have to add per 100 gallon to oxidize the sulfur?

http://www.problemwaterfixed.com/peroxide.htm

The theoretical weight ratio of hydrogen peroxide to hydrogen sulfide is 1:1. You probably need more to make the reaction work.

To keep it simple and accurate enough for estimates, and recognizing that you may need more because of other reactions, losses, and higher concentration needed to drive the reaction, I offer the following theoretical estimate:

A 35% solution is 350,000 parts per million.

Your hydrogen sulfide is 10 parts per million.

Therefore, one gallon of 35% hydrogen peroxide would treat 35,000 gallons of water at 10 parts per million.

To answer your specific question:
10 ppm x 100 gallons /350,000 = 1/350 gallon = 2.2 teaspoons = 11 ml

You need to find an answer from someone who has used peroxide to get an answer on the real number. I would not be surprised to find that you need 3 to 5 times the theoretical value.

Why not use air or bleach. I don't like to promote bleach for anything, but in your case it may be better than peroxide.

Air can also get rid of the hydrogen sulfide odor. We have a system that does just that.

bob...

http://www.solvayinterox.com.au/MSDS/Contolling reduced suphur species.pdf

Most of the references to treating water for Hydrogen Sulfide are related to wastewater that that has high concentrations of H2S. The paper at the link above discusses the various processes and points out that the process works best at pH just below neutral (slightly acidic).

The reaction time is described as "minutes". You may need to have a contact tank that would require 3 to 5 minutes contact time. If you can arrange to inject it into the well near the pump inlet you will get good mixing and may not need a separate tank.

There are systems that are designed and sold to treat sulfides with peroxide. That will probably be easier than trying to do a home-brewed system. My nature is to try things like that and I would try some things myself, but would not try to gaurantee a system for a customer with what I know now.

One advantage of peroxide over chlorine is that it doesn't produce dangerous byproducts that you might get from high levels of chlorination required to handle 10 ppm of H2S.

actual question

My question actually is how much would it take to oxidize the sulfur, not how much to get a 1:1 ratio.

ferd said:

My question actually is how much would it take to oxidize the sulfur, not how much to get a 1:1 ratio.

Click to expand...

The amount it takes to decompose the Hydrogen Sulfide is equal to the amount of Hydrogen Sulfide. That is how the 1:1 ratio is arrived at.

Your question was:
"Having well water with 10 ppm of sulfur, how much 35% peroxide do I have to add per 100 gallon to oxidize the sulfur?"

The first thing that must be done is analyze the chemistry.

Each molecule of H2S requires one molecule of H2O2 to decompose it.

The atomic weight of sulfur is 32, oxygen 16, and hydrogen 1. Therefore, the molecular weight of H2S is 34 and the molecular weight of H2O2 is 34. Since they are the same, the weight ratio is 1:1.

So to figure out much H2O2 you need to neutralize 10 mg/L of H2S in 100 gallons of water using 35% H2O2 you must figure out how much H2S is in the water and use an EQUAL AMOUNT (1:1 ratio) of H2O2. Then you must account for the fact that the H2O2 is only 35%.

The answer is that you need about 2.2 teaspoons.

Pressurized aeration, like air pumps or air injection systems may not remove all the H2S. I've never heard of anyone using peroxide for high H2S but if you have sufficient solution strength and sufficient retention, it may work. If not and you are using a solution feeder, then your only choice is liquid chlorine. Or other equipment.

Either way, a solution feeder is usually a real PIA to keep adjusted as your solution strength weakens in the tank. That happens constantly with chlorine injection. The bleach/chlorine will settle to the bottom of the tank just after mixing ther solution and then the pickup is on the bottom of the tank so you suck up the stronger solution but it is weakening as soon as you mixed it. So you are never injecting a constant strength solution. Then you'll raise the amount you inject and use the solution up sooner and go back to the strongest solution and this repeats constantly.

I use an erosion chlorine pellet chlorinator and special mixing/retention tank equivalent to a regular 120 gallon retention tank. Then a backwashed special type carbon filter.

As to how much peroxide, the people you buy the solution feeder from should be able to tell you. And if not, I wouldn't buy from them.

Hydrogen sulfide is a contaminant in wine making, and peroxide is approved for its removal. Its fairly commonly used, though not admitted by winemakers.

Copper sulphate is also used, and historically pieces of copper plate were suspended in wine barrels to clean up odd odors.