Recently, we had a potential customer who purchased a backwashing carbon filter from another company. The customer was still experiencing a severe sulfur smell as carbon generally does not remove hydrogen sulfide from water, so they contacted the company that sold them the backwashing carbon filter. The company told the customer to call US Water Systems and get a chlorination system to use conjointly with their carbon filter.

The company recommended us for a reason. US Water Systems has the reputation of knowing how to treat water that other companies walk away from. However, recommending that the customer get a chlorination system from us was an unfortunate suggestion and based upon completely erroneous information, to make matters worse, the company told the customer this:

“We can't find anything that states that hydrogen peroxide is bad or can damage carbon; however, we also do not believe the water will be safe to drink.”

Not only is that wrong, but it is also reckless. But before we get into why chlorination is not a good option for removing either sulfur odor or hydrogen sulfide from the water, let’s consider how that rotten egg odor gets into a water supply in the first place.

 Sulfur and Hydrogen Peroxide

Sulfur is a naturally prevalent element in various forms and compounds throughout the Earth's crust. The presence of sulfur compounds is often detectable due to their distinctive odor. In aqueous environments, sulfur commonly exists as dissolved hydrogen sulfide (H₂S) gas, recognizable by its infamous rotten egg smell. This gas is a major component of sewer gas, therefore, water with elevated sulfur content is frequently described as having a sewer-like odor.

Hydrogen sulfide can infiltrate water supplies through two primary mechanisms. Firstly, it is a byproduct of the anaerobic decomposition of organic matter, such as decaying plant material underground, which can dissolve in local groundwater. This occurrence is typical in regions with significant coal deposits, oil fields, or high concentrations of shale or sandstone. Secondly, hydrogen sulfide is mostly generated by sulfur-reducing bacteria that thrive in low-oxygen environments, commonly found in deep wells and water distribution systems.

 Hydrogen Peroxide’s Chemical Formula is H2O2, while its chemical name is dihydrogen dioxide. Hydrogen peroxide is both an effective disinfectant and a powerful oxidizer. As a disinfectant, it produces free radicals that attack essential cell components, making it effective against a wide range of microorganisms, including bacteria, viruses, and fungi. As an oxidizer, hydrogen peroxide can break down organic and inorganic materials through oxidation, making it useful in various industrial and environmental applications.

Effective Oxidizers 

While chlorine may be a better disinfectant, it is not nearly as powerful as an oxidizer as hydrogen peroxide. Some companies in the water treatment industry have been slow to embrace hydrogen peroxide technology and instead (to their detriment) embrace a technology (chlorination) that is dramatically inferior to the oxidation of sulfur with hydrogen peroxide.

I started in the water treatment industry in 1972 and have been continuously involved. I have trained hundreds or probably thousands of people in water treatment fundamentals and I am currently the longest-tenured Master Water Specialist by the WQA (Water Quality Association). I was also one of the early pioneers in hydrogen peroxide technology over 30 years ago. We have tens of thousands of hydrogen peroxide systems installed across the United States and Canada. I am not saying this to brag but to establish that I do have the credentials to demonstrate my expertise and credibility in this field.

Oxidation is the most effective way to remove hydrogen sulfide or iron bacteria from a water supply. Oxygen, Hydrogen Peroxide, and Ozone are the most economically practicable oxidizers. Without considering cost, Ozone is the best oxidizer with an oxidation potential of 2.1, followed by Hydrogen Peroxide with 1.8 then Chlorine with 1.5. The fact is that a properly engineered ozone system will be three to five times the cost of a hydrogen peroxide system, so that is generally cost-prohibitive.

Disinfection By-Products 

Another insidious issue with chlorine that you do not get with hydrogen peroxide is Disinfection By-Products or DBPs. Disinfection by-products (DBPs) are chemical compounds formed when disinfectants used in water treatment, such as chlorine, chloramine, or ozone, react with natural organic matter, inorganic substances, or bromide/iodide present in the water. These by-products can include a variety of chemicals, some of which are potentially harmful to human health. Common DBPs include:

1. Trihalomethanes (THMs): A group of chemicals that includes chloroform, bromoform, and bromodichloromethane. THMs are formed when chlorine reacts with natural organic matter.

2. Haloacetic Acids (HAAs): A group of chemicals that includes monochloroacetic acid, dichloroacetic acid, and trichloroacetic acid. HAAs are formed by the reaction of chlorine with organic matter.

3. Chlorite and Chlorate: Formed primarily when chlorine dioxide is used as a disinfectant.

4. Bromate: Formed when ozone reacts with bromide ions in the water.

5. N-Nitrosodimethylamine (NDMA): Formed from the reaction of chloramine with certain organic nitrogen compounds.

Exposure to some DBPs has been linked to adverse health effects, such as an increased risk of cancer and reproductive issues. Therefore, the concentration of these by-products is regulated in drinking water to ensure safety.

Why inject chlorine into water that may have an odor, but is otherwise devoid of those Disinfection By-Products? And then have to make sure you have enough carbon to remove them to make the water safe? Why do that if you don’t have to? There is a better way and it involves Hydrogen Peroxide which produces no Disinfection By-Products.

Hydrogen Peroxide Technology 

Hydrogen Peroxide or H2O2 reverts to the elements of water (H2O) after oxidation. It is important to understand that standard Granular Activated Carbon or GAC is not to be used with Hydrogen Peroxide. We recommend using a coconut shell Catalytic Carbon as it accelerates the oxidation process.

US Water Systems are the experts in Hydrogen Peroxide Technology. In the interest of full disclosure, I will explain why we are the unquestioned experts in this technology, it’s simple, nobody has made more mistakes than us. We made every mistake in the book and then some. Thomas Edison is famously quoted as saying, "I have not failed. I've just found 10,000 ways that won't work." This statement reflects his perspective on perseverance and the iterative process of experimentation and learning from mistakes in inventing the light bulb. Sometimes I feel like we have made over 10,000 mistakes in H2O2 Technology, but we got them all out of the way and now our systems operate flawlessly for 15 to 20 years.

We have some systems that are still operating that are almost thirty years old. We know what works and what doesn’t because we learned the hard way. For example, here are a few things to avoid when installing a Hydrogen Peroxide System:

•  Do not use a static mixer. It destroys some of the air bubbles, diminishing its oxidation ability.
• Do not use a contact tank. A contact tank dilutes the hydrogen peroxide's strength. Remember, we are using it as an oxidizer, not a disinfectant!
• Do not use a flow switch. Use a proportional injection system with a meter that adjusts the hydrogen peroxide flow based on the flow rate.
• Use Coconut Shell Catalytic Carbon. Do not use coal-based catalytic carbon or standard GAC.
• Do not starve the system of peroxide. Not using enough hydrogen peroxide will wreck the carbon media.
• Replace the Catalytic Carbon every five years. Typically, the media needs to be replaced every 5 years. Just do it!

Hydrogen peroxide is a time-proven and extremely safe technology to remove Hydrogen Sulfide and Iron from your water supply. The water will be safe to drink and you will enjoy the non-odorous emanations of your water supply.

While a Hydrogen Peroxide System will also kill bacteria, if your water supply is contaminated with e-Coli or coliform bacteria, I would recommend an Ultraviolet Disinfection System as a better solution for Disinfection than Hydrogen Peroxide or Chlorine.

 Pictured above is our Matrixx Infusion Hydrogen Peroxide Iron and Sulfur Eradication System.

In summary, hydrogen peroxide is an excellent treatment method for removing iron and sulfur from water. Here are the key points on using hydrogen peroxide to treat iron and sulfur in water:

• Hydrogen peroxide is a powerful oxidizing agent that can oxidize dissolved iron (Fe+2) to an insoluble ferric (Fe+3) state, allowing the iron or sulfur to precipitate and be filtered from the water. It is more effective than chlorine for treating iron and sulfur.
• For hydrogen sulfide (rotten egg smell), hydrogen peroxide oxidizes the sulfide compounds, breaking them down into sulfur particles that can then be filtered out. It works faster than chlorine at eliminating sulfur odors.
•  Hydrogen peroxide releases dissolved oxygen into the water, which has a strong oxidizing effect to destroy odors and oxidize iron, manganese, and other contaminants.
• A major advantage of hydrogen peroxide over chlorine is that it does not produce harmful chemical byproducts - it simply breaks down into oxygen and water. This avoids issues like trihalomethanes formed from chlorine. Hydrogen peroxide is relatively easy to handle and often does not require a contact tank before filtration, reducing system complexity.
•  It is one of the strongest oxidizers available for water treatment, second only to ozone and hydroxyl radicals. It has a higher oxidizing potential than chlorine, chlorine dioxide, and potassium permanganate.
•  Catalytic carbon filters effectively remove any residual hydrogen peroxide after treatment.