ACTIVATED CARBON AIR TREATMENT – THE SCIENCE
What is Activated Carbon?
Activated carbon (also referred to as an activated charcoal), is used in various forms for odour & Emission control.
Systems using carbon filtration media banks are used to control these emissions and other harmful airborne chemicals released from industrial processes. Activated carbon is highly effective at removing odours from a number of industrial processes when used correctly.
Activated Carbon Filtration System Designed To Your Needs
We can design and install a complete system to meet your specific requirements, following a detailed assessment. Read more about our range of Deep Bed Carbon filter systems here.
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Biogas Carbon Filtration for Odour Control
Biogas operations, such as anaerobic digestion and landfill gas recovery, often generate sulphur compounds, ammonia and volatile organic compounds (VOCs) that cause persistent odours and emissions. Exeons hi-flo activated carbon filter offers a robust solution by using a tailored bed of activated carbon to specifically capture these odorous molecules.
The activated carbon used is often impregnated with chemical agents (e.g. potassium iodide, sodium hydroxide, or metal salts) that enhance its affinity for hydrogen sulphide, mercaptans and ammonia. As the biogas passes through the carbon bed, odorous gas molecules are adsorbed onto the internal pore surfaces and chemically neutralised, preventing breakthrough. The design ensures optimal contact time and flow distribution to maximise removal efficiency even under fluctuating load conditions.
In practice, a biogas carbon filter fits downstream of primary scrubbing or desulphurisation stages, polishing residual odour before release or use. Its modular design allows for staged replacement, regeneration or maintenance without full system downtime. The result: compliant off-gas quality, minimal odour nuisance, and enhanced public acceptance of biogas plants. Integrating a biogas carbon filter ensures that your odour control strategy remains comprehensive, efficient and resilient.
How it works
Activated carbon has been used since the First World War to protect infantry against chemical gas attack.
The base material can be coal, wood or even peat, but the best quality carbon uses coconut shells. The material is chemically or thermally treated, usually with superheated steam, to expose the internal pore structure. This increases the surface area by over 100 times. A teaspoonful of carbon can have the surface area of a football pitch.
The vast surface area and tortuous route through the pore structure encourages molecular to surface collisions. “Van der Waal” forces cause molecules to attract and remain within the carbon structure, this is known as “adsorption”.
A carbon block filter is typically in pellet or granular form in beds, arranged so that air can pass through. The time the air is in contact with the carbon block is known as “dwell” or “contact” time. Typical dwell times range from 0.2 seconds to 10 seconds, depending on the application.
When the bed is “saturated” with contaminant, then “breakthrough” is experienced, with emissions rising. This means the bed is exhausted and no further adsorption can take place.
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