Activated Carbon for Water Treatment

How activated carbon works

Activated carbon is carbon that has been processed to create a huge network of tiny pores. A single gram can have a surface area of several hundred square metres or more. As water or air flows through, many dissolved organic substances stick to this surface. This is called adsorption. Chlorine is handled differently: the carbon surface reacts with it and breaks it down.

In water treatment activated carbon removes:

• Chlorine, which carbon breaks down by a surface reaction, protecting RO membranes and improving taste. Chloramine needs a catalytic carbon grade and longer contact time; ask us.
• Taste, odour and colour from surface water, borewell water and treated effluent.
• Organic chemicals such as some pesticides, solvents and oil traces.

It does not remove dissolved salts (TDS), hardness, nitrates or most metals, and it does not reliably remove bacteria. Pair it with the right other treatment: see RO, softeners and filter media.

Types of activated carbon

What to check when buying activated carbon

• Iodine number: a common indicator of how much fine pore surface the carbon has. Higher usually means more adsorption capacity for small molecules.
• Mesh size: the granule size range. Smaller granules adsorb faster but cause more pressure drop.
• Hardness and ash: hard carbon creates less dust during backwash; low ash means purer carbon.
• Raw material: coconut shell for drinking water and chlorine removal; other raw materials can suit larger organic molecules and colour.
• Moisture and apparent density: affect how much carbon you actually get per bag and per filter.

Filling and maintaining a carbon filter

1. Size the filter: give us the vessel diameter and bed depth, or the flow rate, and we estimate the quantity.
2. Load and soak: add carbon over the support gravel, fill with water and let it soak so trapped air escapes.
3. Backwash: backwash thoroughly to remove fines before putting the filter in service.
4. Replace on time: carbon gets used up. Replace it when chlorine, taste or odour start to break through.

Who uses our activated carbon

• RO plant OEMs and integrators
• Packaged drinking water plants
• Domestic and commercial water filter makers
• Housing societies
• Hotels and hospitals
• Effluent and sewage treatment plants
• Aquariums and fish farms
• Air purification and odour control
• Sugar, chemical and pharma decolourising
• Gold recovery

Activated Carbon: product range

Each product line has its own page with uses, dosing guidance and FAQs.

• Granular Activated Carbon (GAC)
• Powdered Activated Carbon (PAC Carbon)
• Pelletised (Extruded) Activated Carbon
• Silver-Impregnated Activated Carbon

Frequently asked questions

What is activated carbon used for in water treatment?

Activated carbon removes chlorine, taste, odour, colour and many organic chemicals from water. It is widely used in carbon filters before RO plants, in drinking water filters and for polishing treated effluent.

Does activated carbon remove TDS?

No. Activated carbon does not remove dissolved salts (TDS), hardness or nitrates. Reverse osmosis or ion exchange is needed for that.

What is the difference between GAC and powdered activated carbon?

Granular activated carbon (GAC) is used in filter beds that water flows through and can be backwashed. Powdered activated carbon is dosed directly into water and removed with the sludge, which suits occasional taste, odour or colour problems.

Why use coconut shell activated carbon?

Coconut shell carbon is hard, produces little dust and has many fine pores, which makes it very good for chlorine removal and drinking water applications.

What is the iodine number of activated carbon?

The iodine number measures how much iodine a gram of carbon adsorbs. It is a common indicator of fine pore surface area and adsorption capacity for small molecules.

How often should activated carbon be replaced?

It depends on the water and the load. Replace the carbon when chlorine, taste or odour start to come through. Many plants test the filter outlet for chlorine regularly.

What is silver-impregnated activated carbon?

It is granular activated carbon treated with silver to limit bacterial growth inside the carbon bed, commonly used in point-of-use drinking water filters.

How much activated carbon do I need for my filter?

Share your filter vessel diameter and bed depth, or the flow rate, and we will estimate the quantity of carbon needed.