Aeration and Oxidation In Well Water Treatment Explained

Iron, manganese, and hydrogen sulfide gas often exist together in groundwater supplies. One of the most effective alternatives to chemical oxidation for removing these contaminants is aeration and oxidation.

Here, we’ve shared everything you should know about aeration and oxidation for private wells, including how the aeration process works, its benefits, and considerations you should make before installing an aeration system.

❔ What is Aeration and Oxidation?

Aeration (air injection) and oxidation is a process that oxidizes and captures several contaminants commonly found in well water, including iron, hydrogen sulfide, manganese, carbon dioxide, volatile organic compounds (such as industrial solvents and MTBE), and methane.

The process takes place in an oxidation tank and is typically combined with a filtration media, like birm or manganese greensand, which traps the oxidized contaminants and prevents them from continuing through your home in the water supply. These precipitated contaminants can then be flushed down a drain line when the system backwashes.

There are aeration systems available for domestic well water treatment, as well as systems that are used for industrial processes and wastewater treatment.

⚙️ How Does the Aeration Process Work?

The aeration process works by sending water through a fine bubble of oxygen, then venting the excess air outside.

The dissolved oxygen causes volatile compounds and dissolved gases to be released from water, where they’re vented to an outdoor location.

Contaminants like iron, manganese, and hydrogen sulfide aren’t vented – they’re converted into their insoluble state (precipitated), which can then be easily removed using a flushable filtration media.

The aeration systems that are commonly used for private wells are simple tank-based systems that contain an air pocket at the upper-third portion of the tank and a filtration media at the bottom.

Water flows into the tank and is exposed to the air pocket, which introduces dissolved oxygen. The precipitated contaminants are then trapped in the media bed as water flows out of the system.

You may need to adjust your water pressure following treatment. An easy way to do this is to install a pump downstream of the aeration tank.

⚗️ What Does Aeration & Oxidation Remove from Well Water?

Aeration and oxidation can remove several undesirable gases and organics from well water.

Here are the groundwater contaminants that most aeration and oxygen systems can reduce or remove:

• Iron – Metallic water taste, causes orange/brown staining
• Manganese – Black coloration & staining, may affect the nervous system and brain in high concentrations
• Hydrogen sulfide – Rotten egg odor, unpleasant water taste
• Methane – Alters water chemistry and makes it unpalatable; may cause fire or explosion if it builds up to dangerous levels
• Carbon dioxide – No known health effects in water, but high levels of carbon dioxide may damage the well aquifer
• Volatile organics (such as MTBE or industrial solvents) – Have known health effects, including cancer and liver and kidney damage

🚫 What CAN’T Aeration/Oxidation Remove?

Aeration CAN’T remove heavy metals like lead, arsenic, or copper, or microorganisms like bacteria and viruses. It also can’t remove the likes of fluoride or chlorine, and it doesn’t offer a guaranteed method of nitrate or nitrite removal.

⚖️ Pros And Cons of Aeration for Well Water

Here are the advantages and disadvantages of aeration for well water:

Advantages

Highly Effective Treatment

If you’re interested in an aeration treatment system for well water, there’s a good chance that you’re looking to oxidize iron and manganese, or hydrogen sulfide.

Aeration and oxidation is one of the most effective ways to remove these dissolved minerals – some of the best systems we’ve reviewed offer up to 30 PPM iron removal (much more than you’ll have in your water), and also remove up to 10 PPM of hydrogen sulfide and manganese.

As an added bonus, aeration also offers methane carbon dioxide removal, and can remove some volatile organics.

Chemical-Free Method

Aeration is a chemical-free alternative to chlorination, which achieves similar results but uses chlorine to oxidize minerals.

If you don’t want to add any toxic chemicals to your water and you don’t want the fuss of filtering water to remove these chemicals post-treatment, an aeration system is a good solution for you.

Improves Water Taste/Odor

Aeration removes methane, hydrogen sulfide, iron, and other contaminants and dissolved gases that affect water’s taste and cause odor problems.

You can use an aeration system to improve your well water’s taste and smell, making it more appealing for drinking, cooking, and washing.

Easy To Maintain

Maintaining an aeration tank is easy. The tank will regenerate automatically when necessary, replenishing the oxygen bubble and backwashing the media to remove the accumulated contaminants.

You don’t need to replace any filters (unless the system has a sediment pre-filter), and, thanks to backwashing, the filter media lasts for years before it needs to be replaced.

Fast Results

Unlike chemical treatment, aeration doesn’t require a long contact time between water and the oxidizing agent (the air bubble) for the process to be effective.

Water doesn’t need to be stored in a holding tank for 20-30 minutes before it can be delivered to your home. Ferrous iron, sulfur, and manganese are oxidized almost instantly when dissolved oxygen is introduced to the water.

Disadvantages

Doesn’t Remove All Well Water Contaminants

While aeration can remove carbon dioxide, iron, manganese, sulfur, and several other common well water contaminants, it doesn’t remove heavy metals or microorganisms (which are also found in some groundwater supplies).

You may need to spend money on additional treatment alongside an air injection system depending on what your water contains.

Can’t Remove Iron Bacteria

While other methods of oxidation (namely chlorine, ozone, or hydrogen peroxide injection) can remove iron bacteria, an aeration system can’t remove this contaminant.

In fact, iron bacteria may clog the filter media, preventing it from effectively capturing oxidized contaminants like iron and manganese.

May Reduce Water Flow

The resistance caused by sending water through the oxygen bubble and filter media will slow water flow, potentially affecting your water pressure.

You might need to install a pressure booster pump to ensure water is delivered quickly enough to your appliances and plumbing fixtures.

📖 Considerations to Make Before Buying an Aeration System for Wells

Here are some of the considerations you should make before installing an aeration tank to treat your well water.

Cost/Budget

First, make sure you budget accordingly for this method of drinking water treatment.

An aeration system costs around $1,750-$3,000 on average, depending on the system’s size and complexity.

Maintenance costs are much lower. You don’t have to top up any chemicals, and you’ll only need to replace the filter media every few years.

Additional Contaminants Present

Also consider the other contaminants in your well water that won’t be removed by aeration.

For instance, if your well water is high in arsenic, you’ll need a separate filter, such as a KDF water filter, that can remove this contaminant.

You might want to follow up with a reverse osmosis system, which removes virtually all dissolved solids from groundwater supplies. The aeration system will act as an effective pre-filter, preventing iron fouling in the RO membrane.

Get your water tested by a state-certified laboratory if you’re not sure what it contains.

Pre-Treatment

Depending on the properties of your well water and the contaminants present, you might also need to install a pre-filter upstream of the aeration system.

Typically, aeration is the most effective when water pH is around 8-9. Most systems can work with a pH of 7, but if your well water has a pH of 6.5 or less, you’ll need to consider installing an acid neutralizer system to boost pH before the aeration treatment process.

Many aeration filters come with a built-in sediment pre-filter to protect the tank’s components and media from sediment. If you have a large volume of sediment in your water, you may need a dedicated whole home sediment filter, which will remove a greater range of sand, silt, rust, and other suspended solids.

Water Flow/ Household Size

The flow of water from the system is also something to consider. The average flow rate for an aeration system is 6-20 GPM, depending on the system size.

Make sure to choose the right-sized system for your household size. Aeration devices typically reduce water flow by several gallons per minute, so you might need a booster pump to raise water pressure post-treatment.

System Size & Install Process

You’ll need to install an aeration tank downstream of your well pressure tank but upstream of your hot water heater. Check your available install space and compare your measurements to the system’s dimensions (keeping in mind that you also need space for maintenance).

Installing an aeration system involves intercepting your main water supply line and installing a drain line. If you’re not confident with DIY, you’ll need to consider hiring a professional plumber to install the unit for you – which will, of course, come at an extra cost.

📑 Final Word

Aeration and oxidation is an effective, chemical-free means of oxidizing and removing hydrogen sulfide, iron, and manganese from water, and is also effective in reducing carbon dioxide, methane, and volatile organic compounds.

You can measure the effectiveness of aeration by testing two samples of your water: one collected before and one collected after installing the system. The treated water should have a greatly reduced concentration of dissolved minerals and gases.