An aeration tower is the step most failed borehole plants leave out. Because groundwater is anoxic, dissolved iron, manganese, carbon dioxide and hydrogen sulphide cannot be filtered until they are first exposed to oxygen. An aeration tower does exactly that — it adds dissolved oxygen, strips out unwanted gases and triggers the oxidation that makes iron and manganese filterable. This page explains when you need one, the types available, and how they are sized.
If your water has any of these, the answer is almost always yes.
An aeration tower is required whenever the problem is a dissolved species that has to be oxidised or stripped before the rest of the plant can remove it. A sand or multimedia filter on its own does nothing to these — they are in solution, not suspension. Aeration is the conversion step that makes the downstream filter work.
Aeration oxidises Fe²⁺ to insoluble Fe³⁺ floc that the filter can then capture. The classic, almost universal reason for a borehole aeration tower.
Aeration raises DO and helps oxidise Mn²⁺; manganese is slower, so aeration is paired with catalytic media or an oxidant. See Fe/Mn removal.
Towers strip excess carbon dioxide, raising pH and reducing the corrosiveness of acidic borehole water — protecting pipes, concrete and boilers.
Aeration strips and oxidises H₂S, removing the rotten-egg odour and corrosion risk at the wellhead.
Raising DO supports downstream biological ammonia/iron removal and prevents anoxic conditions in the plant.
Dissolved methane (a safety hazard) and some VOCs are stripped to atmosphere by an aeration tower.
Installing a filter without aeration on iron/manganese water. The filter blinds with floc that forms inside it, or the dissolved metals pass straight through and precipitate downstream. Oxidation must come before filtration — see treatment challenges.
Chosen by the gas-transfer duty, head available and footprint.
| Type | How it works | Best for |
|---|---|---|
| Cascade / tray aerator | Water falls over stepped trays, contacting air | Iron oxidation, simple, low maintenance |
| Packed / induced-draught tower | Water trickles over packing media against an upward air flow (forced/induced fan) | High CO₂/H₂S stripping, high transfer efficiency |
| Spray aerator | Water sprayed through nozzles into air | Oxygenation & iron, where head is available |
| Pressure / in-line aeration | Air or oxygen injected into a pressurised contact vessel | Compact plants, retaining system pressure |
| Diffused aeration tank | Fine-bubble diffusers in a contact tank | Controlled DO, combined with contact time |
The duty is set by the gas you need to add or remove.
The tower output goes to catalytic multimedia filtration — aeration and filtration are designed as one system, not separately.
The exact duty comes from a treatability assessment — iron, manganese, CO₂, H₂S and pH of your actual borehole.
Tell us your borehole’s iron, manganese, CO₂, H₂S and pH and we will tell you whether you need an aeration tower, which type, and how it sizes — then build it into your treatment train.
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