Ammonia Removal from Industrial Air (NH₃)

Ammonia (NH₃) is a common pollutant in industrial air emissions, especially in processes involving organic materials and biological degradation.
Although highly soluble in water, ammonia removal is often more complex than expected in real operating conditions.

It is characterised by a sharp, pungent odour that is immediately perceived even at low concentrations.
In higher concentrations, it can cause irritation to the eyes and respiratory system, making it not only an environmental issue but also an operational and safety concern.

Although highly soluble in water, ammonia removal is often more complex than expected in real operating conditions.

NH3

Ammonia Is Not a Simple Pollutant

Ammonia behaviour depends strongly on process conditions.

  • Absorption is controlled by pH
  • Chemical equilibrium affects removal efficiency
  • Process variability alters performance over time

In unstable conditions, Ammonia removal becomes unpredictable and reagent consumption increases significantly.

3D model of ammonia molecule NH3 showing nitrogen atom bonded to three hydrogen atoms in trigonal pyramidal structure

Common design mistakes

Many Ammonia treatment systems are designed using simplified assumptions.
Typical issues include:

  • Designing based on airflow instead of pollutant load
  • Using single-stage scrubbers for variable emissions
  • Ignoring buffering effects in the liquid phase
  • Underestimating aerosols and particulates

These factors lead to unstable performance and excessive operating costs.

How Ammonia is removed in Industrial Systems

Ammonia removal is based on gas absorption combined with chemical control.
Effective systems typically include:

  • Acid scrubbing stages for ammonia neutralisation
  • Controlled pH conditions
  • Adequate liquid-to-gas ratio (L/G)
  • Proper liquid distribution

For variable or complex emissions, multistage configurations are often required.

Process conditions define performance

The same ammonia concentration can behave differently depending on:

  • temperature
  • humidity
  • presence of other compounds
  • process variability

Selecting a technology without understanding these factors often leads to unstable systems.

Industries with Ammonia Emissions

Ammonia emissions are typical of industrial processes involving organic matter, biological activity and thermal treatment.

Rendering and Animal By-Products (Category 3)

Ammonia is generated during protein degradation and thermal processing.
Emissions are variable and often associated with odorous compounds.

Ammonia and Odour Control in Rendering →

Waste Treatment and Composting

Biological degradation produces ammonia under unstable conditions.
Emission peaks occur during loading and handling phases.

Ammonia Control in Composting Plants →

Pet
Food Production


Raw material variability leads to fluctuating ammonia emissions, often combined with VOCs and odours.

Control Ammonia and VOC Emissions →

Wastewater Treatment Plants

Ammonia is released during biological processes and sludge handling, often together with hydrogen sulfide.

Ammonia and H₂S Removal in WWTP →

FAQ – Ammonia Removal

Ammonia removal is typically achieved through wet scrubbing systems using acid solutions.
The effectiveness depends on pH control, liquid-to-gas ratio and process stability.
In variable industrial conditions, multistage systems are often required to maintain consistent performance.

Ammonia emissions are rarely constant.
Variations in process conditions, temperature, humidity and pollutant load can significantly affect removal efficiency.
Without proper control, this leads to unstable performance and increased reagent consumption.

Sulfuric acid (H₂SO₄) is commonly used in ammonia scrubbing systems because it reacts with ammonia to form ammonium sulfate.
This reaction improves removal efficiency and stabilises the absorption process by maintaining low pH conditions.

Ammonium sulfate ((NH₄)₂SO₄) is a salt formed when ammonia reacts with sulfuric acid in wet scrubbing systems.
In industrial air treatment, it is generated as a by-product of the neutralisation process.
Depending on operating conditions, ammonium sulfate can accumulate in the recirculation liquid and influence system performance, requiring proper management and purge strategies.
It is the most widespread by-product in Ammonia Stripping and Absorption plants.

In some applications, Ammonium Sulfate can be recovered and reused, for example as a fertiliser component.
However, in most industrial air treatment systems, it is managed as a process by-product rather than a primary output.
Its accumulation can affect salinity, scaling and overall system behaviour if not properly controlled.

No.
Ammonia can also be removed using dry scrubbing systems based on adsorbent materials such as natural zeolites.
These systems can be effective under controlled conditions, but their performance depends on humidity, concentration and contact time.

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