How to Remove Iron and Manganese from Well Water

Iron and manganese are two of the most common problems in well water and groundwater, including in many parts of Sarawak and the rest of Malaysia. They are not usually a health risk at typical levels, but they cause orange-brown or black stains on sinks, laundry and tiles, give water a metallic taste, and build up inside pipes, pumps and equipment. This guide explains the main treatment options.

How iron and manganese get into water

As groundwater passes through soil and rock, it dissolves naturally occurring iron and manganese minerals. Underground, where there is little oxygen, these metals stay dissolved and the water looks clear. Once the water is pumped up and meets air, the metals oxidise into solid particles. That is why well water can come out clear and turn cloudy or orange after standing.

Step 1: Test your water

Before choosing a treatment, test for at least:

• Iron and manganese levels (mg/L)
• pH
• Dissolved oxygen
• Hydrogen sulphide (a “rotten egg” smell)
• Hardness and organic matter

These results decide which method will work. A treatment that suits one well can fail completely on another.

Step 2: Choose a treatment method

Catalytic filter media (such as Birm)

Birm is a granular media that speeds up the natural oxidation of dissolved iron and manganese. The metals turn into particles that are trapped in the filter bed and removed by regular backwashing. Birm needs no chemical regeneration, which keeps running costs low. It works best when the water has enough dissolved oxygen and a suitable pH (roughly 6.8 or above for iron, and higher for manganese). Water containing hydrogen sulphide, oil or high chlorine levels needs pre-treatment first.

Oxidation followed by filtration

An oxidising chemical such as sodium hypochlorite or hydrogen peroxide is dosed into the water, then the particles are removed with a sand or media filter. This handles higher iron levels and also treats hydrogen sulphide, but it needs a dosing pump and regular monitoring.

Aeration

Air is introduced into the water to supply oxygen, and the oxidised iron is then filtered out. Aeration is often combined with Birm when the natural oxygen level is too low.

Water softeners

Ion-exchange softeners can remove small amounts of dissolved iron, but high levels will foul the resin. They are best used after a dedicated iron filter.

Step 3: Add polishing if needed

After iron and manganese are removed, an activated carbon filter can remove remaining chlorine from the oxidation step, plus tastes and odours.

Get the right media for your system

MDNR Resources supplies Birm filter media, coconut shell activated carbon and water treatment chemicals across Malaysia, with MSDS and COA. Send us your water test results through our Request a Quote form and we can suggest a suitable setup.