Industrial Air Scrubbers: Types, How They Work, and How to Choose the Right One

An industrial air scrubber removes contaminants — VOCs, hydrogen sulfide, ammonia, chlorine, or other process gases — from a facility's exhaust air stream before it's released, using a bed of treated media that adsorbs the contaminant as air passes through it. The right unit depends on which contaminant you're treating, how much air you need to move, and whether the gas is acidic, basic, or a general odor/VOC mix.

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What Is an Industrial Air Scrubber and How Does It Work?

An industrial air scrubber pulls contaminated air through a vessel packed with a reactive or adsorptive media bed, and releases treated air out the other side. Dry-media systems — the type ERE supplies under the UltraSorber™ line — use activated carbon as the base media, either used as-is for physical adsorption of VOCs and odors, or chemically impregnated to react with and neutralize a specific gas like ammonia or chlorine.

The mechanism differs from a wet scrubber, which sprays a liquid (often a caustic or acidic solution) through the contaminated air stream and requires a recirculating pump, a dosing system, and wastewater disposal. A dry-media unit has no liquid loop: air moves through the carbon bed, the contaminant binds to or reacts with the media, and the spent carbon is replaced or reactivated on a schedule set by the contaminant load — lower maintenance complexity, at the cost of a bed that eventually saturates and needs changeout.

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What Types of Industrial Air Scrubbers Does a Facility Need?

Which scrubber type a facility needs depends on the specific gas or vapor being treated — a general VOC/odor problem, hydrogen sulfide from a wastewater process, or a targeted acid/base gas like ammonia or chlorine each call for a different carbon.

General VOC and Odor Control

For fugitive VOC emissions, tank-filling vapors, fuel-spill remediation off-gas, or general industrial odor, the UltraSorber Air™ Treatment Vessels line covers 500–5,000 CFM across 8 standard sizes, using 810–8,750 lbs of granular activated carbon in a transportable, forklift-mobile carbon-steel vessel with a plenum chamber for even airflow distribution. For smaller, fixed installations — soil vapor extraction off-gas, air-stripper vent treatment, storage-tank vents — the UltraSorber-Air™-500 handles up to 500 CFM from a 2,000 lb carbon charge in a 500-gallon vessel.

Sewage and Wastewater Odor (H₂S)

Hydrogen sulfide and sulphur-compound odor from lift stations, wet wells, and sewage treatment processes need a catalytic activated bituminous-coal-based carbon rather than plain GAC. The UltraSorber-ODOR™ Sewage Odor Air Treatment Units come in 5/10/25/55/250-gallon drum sizes, handling 25–600 CFM depending on drum size — sized to match a single wet well or a full lift-station vent.

Ammonia

Ammonia is a base gas and needs carbon impregnated with an acid — the UltraSorber-AMMO™ Ammonia Air Treatment Units use anthracite coal impregnated with phosphoric acid, in 55/85-gallon drums rated to a 375 CFM maximum (250 CFM recommended for full contact time). This is a common fit for refrigeration plant ventilation, ammonia-based process exhaust, and facility odor complaints tied to ammonia releases.

Chlorine and Acid Gases

Chlorine and other acidic gases need the opposite chemistry — the UltraSorber-CHLORO™ Chlorine Air Treatment Units use anthracite coal impregnated with potassium hydroxide, in the same 55/85-gallon drum format at 150–300 CFM, commonly installed to protect water treatment facility interiors and control chlorine off-gas.

Laboratory Fume Hood Exhaust

Where a lab needs to treat fume hood exhaust without ducting it to atmosphere, the UltraSorber-FUME™ Fume Hood Air Treatment Units use anthracite coal impregnated with potassium hydroxide and potassium iodide, in 55/85-gallon drums at 150–300 CFM — a ductless option for chemical vapor exhaust in laboratory settings.

System	Media	Flow Rate	Best For
UltraSorber Air™ Treatment Vessels	Granular activated carbon	500–5,000 CFM	General VOC/odor, large or mobile installations
UltraSorber-Air™-500	Granular activated carbon	Up to 500 CFM	SVE off-gas, air-stripper vents, fixed installs
UltraSorber-ODOR™	Catalytic activated carbon	25–600 CFM	H₂S / sewage odor
UltraSorber-AMMO™	Phosphoric-acid-impregnated carbon	Up to 375 CFM	Ammonia
UltraSorber-CHLORO™	KOH-impregnated carbon	150–300 CFM	Chlorine / acid gas
UltraSorber-FUME™	KOH/KI-impregnated carbon	150–300 CFM	Lab fume hood exhaust

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Which Contaminants Can an Air Scrubber Remove?

A properly matched dry-media scrubber removes VOCs, H₂S, SO₂, Cl₂, NOx, O₃, amines, indoles, mercaptans, and ammonia — but no single carbon handles all of them equally well, which is why the UltraSorber line splits into contaminant-specific units rather than one universal media.

CCOHS lists the ACGIH-recommended 8-hour exposure limit (TWA) for ammonia at 25 ppm, noting most Canadian jurisdictions set limits close to that value — a reminder that air-treatment media selection isn't just an odor-control decision, it's tied directly to worker exposure limits inside and around the facility. Plain granular activated carbon adsorbs VOCs and general organic odor through physical adsorption; catalytic carbon adds a chemical reaction step that's more effective on H₂S; acid- or base-impregnated carbons neutralize a specific gas through chemisorption rather than relying on adsorption alone. Mixing contaminant types into the wrong media bed — treating ammonia with a carbon meant for chlorine, for example — will underperform badly and burn through the bed faster than spec.

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How Do You Size an Industrial Air Scrubber for a Facility?

Sizing an air scrubber starts with your actual exhaust flow rate in CFM, not the vessel size that looks closest to your budget — an undersized unit either bypasses untreated air or saturates its carbon bed far faster than the rated changeout schedule.

Sizing Steps

1. Measure or calculate your exhaust flow rate (CFM). This comes from the fan, blower, or extraction system's rated output — not an estimate. A unit undersized on CFM either bypasses air untreated or drives contact time below what the media needs to work.
2. Identify the specific contaminant(s). VOC/general odor, H₂S, ammonia, and chlorine each need a different carbon chemistry — confirm this before selecting media, not after.
3. Check contaminant concentration and expected load. Higher concentration or continuous (vs. intermittent) exposure shortens carbon bed life and may call for a larger media charge or more frequent changeout.
4. Confirm pressure drop against your fan/blower capacity. A carbon bed adds static pressure to the system — the existing fan needs enough capacity to push air through the added resistance at your required CFM.
5. Decide on mobility and installation format. A transportable, forklift-mobile vessel (like the Air™ Treatment Vessels line) suits temporary remediation or spill response; a fixed drum unit suits a permanent installation point like a lift station or fume hood duct.

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Should You Choose Dry-Media Adsorption or a Wet Scrubber?

For most industrial odor, VOC, and targeted-gas applications in the CFM ranges above, a dry-media adsorption scrubber is the simpler choice — no recirculating liquid, no chemical dosing system, and no scrubber wastewater stream to manage or discharge. A wet (liquid) scrubber earns its complexity back only at very high gas loading or very high flow rates, where a dry carbon bed would saturate too fast to be economical, and the facility already has the infrastructure to handle a chemical dosing loop and its wastewater.

Canadian facilities also weigh this against provincial and municipal air-emission permit requirements — the Canadian Council of Ministers of the Environment (CCME) coordinates the air-quality guidance that provincial permits are built from, and a documented, contaminant-matched treatment system is generally easier to defend in a permit application than an undersized or mismatched one. For most facilities running standard VOC, odor, ammonia, or chlorine control at the flow rates above, that points toward a dry-media UltraSorber unit sized correctly from the start rather than a wet system carried for headroom it doesn't need.

For ERE's full range of dry-media air treatment systems, see the Air Treatment Systems collection — all six UltraSorber configurations above are stocked and quoted to your CFM and contaminant profile.

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Frequently Asked Questions

What does an industrial air scrubber remove?

A properly matched dry-media air scrubber removes VOCs, hydrogen sulfide, ammonia, chlorine, sulfur dioxide, NOx, ozone, amines, indoles, and mercaptans — the specific carbon media (plain, catalytic, or chemically impregnated) needs to match the target contaminant.

What's the difference between a dry-media scrubber and a wet scrubber?

A dry-media scrubber pulls air through a fixed bed of activated carbon with no liquid loop; a wet scrubber sprays a liquid solution through the air stream and requires a recirculating pump, chemical dosing, and wastewater handling. Dry-media systems are simpler to operate for most industrial VOC, odor, and targeted-gas applications.

How do I know what size air scrubber I need?

Size is set by your exhaust flow rate in CFM (from your fan or blower's rated output) and the specific contaminant and its concentration — both are needed before selecting a vessel size and carbon charge, not flow rate alone.

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Lire en français : Épurateurs d'air industriels : types, fonctionnement et choix