| | |

Scrubber foam problem: root causes

Foam overflow in wet scrubber recirculation tank indicating process instability

Scrubber foam problem: context

In many industrial wet scrubbing systems, foam formation is often dismissed as a secondary or cosmetic issue. In reality, persistent foam is almost always the visible symptom of a deeper process inconsistency.
This insight originates from real operational evidence: a recirculation tank completely filled with stable foam, generated during normal plant operation.

What foam really indicates

Foam inside a scrubber is not random. It is the result of a combination of physical and chemical conditions:

  • Presence of surfactants or organic compounds
  • High gas velocities and turbulence
  • Unstable liquid chemistry (pH, oxidation state, salinity)
  • Accumulation of reaction by-products

When these factors align, foam transitions from transient to persistent.
At that point, it stops being a nuisance and becomes a process variable.

Why Foam Is a Problem

The consequences are rarely limited to aesthetics:

  • Loss of effective liquid–gas contact
  • Carryover of droplets and contaminants
  • Unstable pressure drop
  • Reduced mass transfer efficiency
  • Risk of downstream fouling
  • Cavitation of recirculation pump

In extreme cases, the scrubber continues to operate, but no longer performs its intended function.

The Typical Reaction (and Why It Fails)

The most common response is the addition of antifoam agents.
This approach is appealing because it is immediate and simple.
However, it rarely addresses the root cause.
Antifoam acts on the symptom, not on the mechanism that generates foam. As a result:

  • Consumption increases over time
  • Performance becomes inconsistent
  • Operating costs rise without solving the instability

Engineering Perspective: Treat the Cause, Not the Symptom

Foam must be interpreted within the broader process context.
The correct approach requires asking fundamental questions:

  • What compounds are actually present in the gas phase?
  • Is the chemical regime (acid/base/oxidative) coherent with those compounds?
  • Is the liquid recirculation accumulating by-products?
  • Is the hydraulic design promoting local imbalances?

Only by reconnecting the scrubber to the upstream process can the issue be solved.

Design Implications

Persistent foam often reveals deeper design limitations:

  • Systems designed for steady-state conditions operating under variable loads
  • Lack of pollutant speciation during the design phase
  • Oversimplified assumptions about liquid chemistry
  • Inadequate purge and make-up strategies

In other words, the problem is not the foam itself.
The problem is that the system was never designed to handle the real process conditions.

Key Takeway

A scrubber does not fail when foam appears.

It fails when foam is treated as an isolated issue.

Understanding and controlling the origin of the emission is the only way to restore performance.

Final note

Visible phenomena in industrial systems are rarely superficial.
They are signals.
Ignoring them — or masking them with quick fixes — only delays the real engineering work.

Related Case Studies

  • |

    Wet Scrubbers Do Not Remove Every Pollutant

    Wet scrubbers are often assumed to remove virtually any pollutant in industrial air pollution control — a belief that is both widespread and dangerous.

    “If there is a wet scrubber, the pollutant will be removed.”

    That is not how it works.

    A wet scrubber is not a universal machine.
    It is a gas–liquid mass transfer system.

    And that means something very simple:

    if the pollutant is not compatible with the physical or chemical absorption mechanism, the scrubber cannot operate effectively, regardless of its size.

    The biggest misconception: gas-liquid contact does not automatically mean removal

    Many systems are designed around a flawed assumption:

    • there is a tower,
    • there is water,
    • there is recirculation,
    • therefore the problem is solved.

    In reality, a scrubber does not generically “capture” molecules.
    A wet scrubber only works if at least one of the following conditions exists:

    • the pollutant is soluble in the liquid;
    • the pollutant chemically reacts in the liquid phase;
    • the pollutant is associated with particulate or aerosols that can be intercepted;
    • thermodynamic conditions favor mass transfer.

    If these conditions do not exist, the contaminant simply passes through the system.

    Some pollutants are naturally treatable

    Compounds such as:

    • Ammonia (NH₃),
    • Hydrogen Chloride (HCl),
    • Sulfur Dioxide (SO₂),

    have properties that allow:

    • dissolution,
    • neutralization,
    • oxidation,
    • relatively efficient absorption.

    In these cases, wet scrubbers can achieve very high removal efficiencies.
    But that does not mean the same approach works for every contaminant.

    VOCs: the reality is far more complex

    Many volatile organic compounds (VOCs) have:

    • low solubility,
    • hydrophobic behavior,
    • high volatility,
    • unfavorable absorption kinetics.

    In practical terms:

    simple contact with water is often insufficient.

    Yet it is still common to see scrubbers designed as if every VOC could simply be “washed out.”

    It cannot.

    Some solvents pass through the tower almost unaffected.
    Others require:

    • specific reagents,
    • oxidation stages,
    • contact times incompatible with real tower geometry,
    • or completely different technologies.

    Methane cannot be “scrubbed” either

    Methane is one of the clearest examples.
    It has:

    • extremely low solubility,
    • high chemical stability,
    • virtually no useful reactivity in conventional wet scrubbers.

    For this reason:

    methane is not treated effectively with traditional wet scrubbers or biofilters.

    It must either be oxidized, diluted, or managed through completely different process strategies.

    Believing that methane can be removed simply by increasing water flow or chemical dosage means misunderstanding the physics of the process itself.

    Chemistry matters more than the machine

    wet scrubber internal

    One of the most common mistakes in air pollution control is treating the scrubber as a standardized product.

    In reality:

    pollutant chemistry comes before equipment selection.

    Without understanding:

    • speciation,
    • actual concentrations,
    • temperature,
    • humidity,
    • aerosol presence,
    • process variability,

    it is impossible to determine:

    • whether a scrubber will work,
    • which chemistry should be used,
    • what liquid-to-gas ratio is required,
    • what pressure drop is necessary,
    • or whether the selected technology is fundamentally wrong.

    A scrubber does not create selectivity out of nowhere

    Another common misconception is that adding:

    • more stages,
    • more chemicals,
    • more recirculation,
    • more complexity,

    automatically allows treatment of any emission stream.

    But no system truly “sorts” molecules.

    Every compound has:

    • its own solubility,
    • its own kinetics,
    • its own chemical behavior,
    • its own equilibrium conditions.

    Inside real industrial gas mixtures:

    • some pollutants are absorbed,
    • others pass through,
    • others interfere with each other.

    This is why truly effective systems are not built from standard catalogs, but from a deep understanding of the upstream industrial process generating the emissions.

    The real goal: designing around the machine instead of the process

    Most failures originate here.
    First, the equipment is selected:

    • “a scrubber,”
    • often because it is available,
    • inexpensive,
    • or already used elsewhere.

    Only afterwards does the engineering attempt to adapt it to the actual pollutants.

    But the correct sequence is the opposite:

    • understand the industrial process;
    • identify the pollutants;
    • understand their physical and chemical behavior;
    • only then design the treatment system.

    Conclusion

    Wet scrubbers can be extremely effective technologies.

    But only when:

    • the contaminant is compatible with the absorption mechanism,
    • the chemistry is correct,
    • mass transfer conditions are realistic,
    • and the system is designed around actual operating conditions.

    because:

    A scrubber does not remove “everything.”
    Removing a pollutant first requires understanding it.

    Industrial wet scrubber installation with quote about pollutant removal and process understanding, featuring a polypropylene scrubber tower during field assembly and maintenance.
  • |

    Odour Control for Biological Sludge Composting

    Technical summary

    Flow rate: 88,000 m³/h
    Industry: Biological sludge composting (municipal wastewater sludge + green waste)
    Technology: Multiventuri scrubber + two-stage packed column scrubber (acid + alkaline/oxidative)
    Target pollutants: Odour, ammonia, hydrogen sulphide, VOC
    Process air condition: Intermittent emissions with high odour load during loading/unloading phases

    Process-driven design for intermittent high-load emissions (88,000 Nm³/h)

    Application context

    Odour Control for Biological Sludge Composting requires a clear understanding of how emissions are generated during the composting of municipal wastewater biological sludge mixed with green waste.

    The plant treats approximately 88,000 Nm³/h of extracted air from:

    • Sludge unloading areas
    • Mixing and structuring phases
    • Composting tunnels
    • Mechanical handling operations

    The composting objective is to stabilise organic matter and produce agronomically valorisable compost through controlled aerobic degradation.

    When properly managed, composting itself does not necessarily generate severe continuous odour levels. The dominant issue lies elsewhere.

    Intermittent peak emissions during sludge unloading

    In biological sludge composting, emissions are predominantly intermittent rather than continuous.

    The highest odour peaks occur during:

    • Sludge unloading
    • Initial mixing with structuring green waste
    • Mechanical agitation of fresh material

    Fresh biological sludge may contain anaerobic microenvironments formed during storage and transport. When exposed to oxygen during unloading, rapid release occurs of:

    • Ammonia (NH₃)
    • Hydrogen sulphide (H₂S)
    • Reduced sulphur compounds
    • Volatile organic compounds
    • High humidity and bioaerosols

    Designing Odour Control for Biological Sludge Composting based on average conditions would underestimate these peak events.

    Engineering challenge at 88,000 Nm³/h

    The system had to manage:

    • High ammonia concentrations
    • Hydrogen sulphide spikes
    • Variable aerosol loads
    • Near-saturated humidity
    • Short-duration high-intensity emission events

    The primary design parameter was therefore peak load management, not nominal airflow alone.

    Multiventuri pre-conditioning stage

    Multiventuri scrubber for Air Pollution and Odour Control in biological sludge composting plant showing independent venturi stages and recirculation piping
    Multiventuri stage designed to manage intermittent high-load odour peaks during biological sludge unloading.

    A multiventuri stage was installed upstream of chemical scrubbing as structural gas conditioning.

    In Odour Control for Biological Sludge Composting, this stage provides:

    • Aerosol reduction
    • Gas homogenisation
    • Initial contaminant absorption
    • Peak concentration damping

    By distributing airflow across multiple venturi throats, the system avoids localised overload during unloading events and stabilises downstream chemical treatment.

    Compact dual chemical scrubbing system

    Following pre-conditioning, the gas enters two vertical scrubbers operating in sequence:

    Acid stage

    Dedicated to Ammonia neutralisation.

    Basic-oxidative stage

    Dedicated to hydrogen sulphide and reduced sulphur compound oxidation.

    Separating chemical environments ensures:

    • Stable pH control
    • Independent reagent dosing
    • Controlled reaction kinetics under variable load

    This sequential architecture is central to effective Odour Control for Biological Sludge Composting at high airflow rates.

    Environmental outcome

    The installation was implemented to mitigate odour impact affecting surrounding residential areas.

    By addressing the intermittent and peak-driven nature of emissions, the system achieved stable odour mitigation despite variability in sludge composition and seasonal factors.

    Engineering insight

    In Odour Control for Biological Sludge Composting, understanding the biological origin of emissions is essential.

    The most critical emissions are:

    • Linked to anaerobic-to-aerobic transition
    • Triggered by sludge exposure
    • Concentrated during short operational windows

    Effective treatment at 88,000 Nm³/h requires architecture capable of absorbing shock loads and stabilising highly variable gas streams.

    Process-driven engineering, rather than average-based design, determines performance.

  • | |

    Wet Dust Scrubbing: Why Packed Bed Scrubbers Fail with Particulate Matter

    Introduction

    Example of packed bed scrubber failure due to dust accumulation and agglomeration of particulate matter in wet scrubbing system

    This is what happens when a packed bed scrubber is used for wet dust scrubbing.
    Dust does not get removed. It accumulates. And over time, it transforms a process unit into a solid mass.
    Most industrial wet scrubbers are not designed for dust removal. Yet packed columns are still widely applied in systems where particulate matter is dominant.
    The result is predictable: fouling, pressure drop increase, and loss of efficiency.

    What You Are Looking At

    The material shown here is not simple contamination.

    It is a compacted mass of:

    • fibrous particulate matter
    • fine dust
    • moisture-bound solids

    The interaction between particles and liquid leads to:

    • agglomeration
    • adhesion to surfaces
    • progressive densification

    Over time, the original structure of the packing disappears.

    This is not fouling.
    This is structural failure of the packing.

    Why Packed Bed Scrubbers Fail with Dust

    Packed bed scrubbers are designed for mass transfer, not for solid particle removal.
    Their operating principles rely on:

    • gas-liquid contact surface
    • residence time
    • chemical absorption

    However, dust removal follows completely different mechanisms:

    • inertial impaction
    • interception
    • diffusion

    These mechanisms require high gas velocities and energy input, which are not present in packed columns.

    As a result:

    • particles are not effectively captured
    • they deposit on the packing
    • accumulation begins immediately

    The Hidden Mechanism: When Dust Meets Water

    One of the most underestimated aspects of wet dust scrubbing is the behavior of particulate matter in the presence of moisture.
    Depending on the nature of the dust, you may observe:

    • hygroscopic effects
    • increased cohesion
    • formation of fibrous or paste-like structures

    Instead of being washed away, particles:

    • stick together
    • attach to surfaces
    • grow into larger agglomerates

    This is a cumulative process.

    And it does not stabilize.

    What Happens Inside the Scrubber

    The failure does not occur suddenly. It follows a predictable sequence:

    • Initial deposition on the packing
    • Localized obstruction
    • Increase in pressure drop (ΔP)
    • Maldistribution of liquid and gas
    • Formation of preferential paths (channeling)
    • Loss of contact efficiency
    • Progressive blockage

    At a certain point, the scrubber is no longer performing gas treatment.

    It becomes a restriction in the system.

    The Design Mistake

    The root cause is not maintenance.

    It is design.

    Many systems are selected based on:

    • air flow rate
    • general assumptions about “scrubber performance”

    What is often ignored:

    • particle size distribution
    • dust concentration
    • physical behavior of solids
    • interaction with water

    A packed bed scrubber is simply the wrong tool for particulate-dominated streams.

    The Right Approach to Wet Dust Removal

    Effective wet dust removal requires mechanical capture mechanisms, not just surface area.

    Venturi Scrubbers

    Venturi scrubbers operate at high gas velocities and generate:

    • strong inertial impaction
    • fine droplet formation
    • efficient particle capture

    Performance is directly linked to pressure drop, which can be controlled and designed.

    Multiventuri systems

    For variable conditions:

    • multiple stages improve efficiency
    • better handling of fluctuating loads

    Pre-Separation (when required)

    In some cases:

    • cyclones filters
    • inertial separators

    can reduce the load before wet treatment.

    Engineering Implications

    Designing a wet scrubbing system for dust requires:

    • understanding the nature of the particulate
    • evaluating interaction with moisture
    • selecting the correct capture mechanism
    • accepting the energy cost associated with efficiency

    The idea that any scrubber can remove dust “if properly sized” is incorrect.

    Conclusion

    You don’t choose a scrubber.
    You choose a mechanism.

    And if the mechanism is wrong, no amount of liquid will fix it.

    If your scrubber is experiencing fouling, scaling, or loss of efficiency over time,
    the issue may not be maintenance. It may be the wrong technology.

  • | |

    Why Your Ammonia Scrubber Is Not Working

    On paper, ammonia removal with a wet scrubber looks simple.
    Add acid. Control pH. Remove NH₃.

    In reality, many industrial scrubbers fail to remove ammonia consistently — even when all “parameters” seem correct.

    If your ammonia scrubber is not working, the problem is rarely a single variable.
    It is almost always a process issue, not a component issue.

    The Real Problem

    Ammonia absorption is not just a chemical reaction.
    It is a mass transfer process limited by:

    You don’t have “a pH”.

    Most scrubbers fail because they are designed as equipment, not as process systems.

    Why It Happens

    1. pH control is not enough

    Lowering pH shifts ammonia (NH₃) into ammonium (NH₄⁺), which is soluble.

    But:

    • local pH ≠ bulk pH
    • poor mixing creates zones where ammonia is not absorbed

    You don’t have “a single pH value”.
    You have a distribution of pH conditions inside the tower.

    2. L/G Ratio Is Too Low

    Ammonia absorption requires sufficient liquid flow.

    If the liquid-to-gas ratio (L/G) is too low:

    • contact area is reduced
    • absorption capacity is limited

    Typical failure:

    Scrubber sized on airflow only → insufficient liquid phase

    3. Poor Liquid Distribution

    Even with correct flow rate:

    • uneven spray
    • asymmetric piping
    • clogged nozzles

    create preferential paths.

    poor liquid distribution in wet scrubber nozzle spray pattern
    • Gas bypasses the liquid
    • Efficiency collapses

    This is one of the most underestimated causes of failure.

    4. Buffering Systems in the Liquid

    This is where most engineers get it wrong.

    In real systems:

    • carbonates
    • bicarbonates
    • ammonium salts

    create buffer systems

    Result:

    • pH does not drop as expected
    • acid consumption increases
    • ammonia removal becomes unstable

    The problem is not dosing.

    The problem is chemistry equilibrium.

    5. Insufficient Contact Time

    Short towers, high velocity, or undersized packing:

    • reduce residence time
    • limit absorption

    Ammonia removal is not instantaneous

    It requires time + interface

    6. Gas Conditions Are Ignored

    Temperature and saturation matter.

    • hot air reduces solubility
    • low humidity limits absorption
    • low humidity limits absorption

    A scrubber designed for “nominal conditions” will fail in real operation.

    What Most Engineers Get Wrong

    • Designing based only on airflow
    • Assuming pH = performance
    • Ignoring liquid distribution
    • Treating ammonia as a “simple pollutant”
    • Oversimplifying chemistry

    What Actually Works

    An ammonia scrubber works when:

    • L/G ratio is correctly sized
    • liquid distribution is uniform
    • pH is controlled considering buffering systems
    • contact time is sufficient
    • process variability is included in design

    This is not about adding more acid.
    It is about designing the system as a whole.

    When the System Cannot Work

    There are cases where:

    • tower is undersized
    • gas load is too high
    • variability exceeds design limits

    In these situations:

    • no adjustment will fix the problem
    • only a redesign or revamping will

    Can an Existing Scrubber Be Fixed?

    Sometimes, yes.

    Typical interventions:

    • increase liquid recirculation
    • redesign distribution system
    • introduce a second stage
    • modify chemical control strategy

    But:

    • not all systems are recoverable
    • and not all problems are “operational”

    Final Insight

    Ammonia removal is not difficult.

    But stable ammonia removal in real industrial conditions is.

    Is your ammonia scrubber underperforming?

    Contact us for a technical evaluation
  • |

    Two-Stage Packed Column Scrubber for Pet Food Air Pollution Control

    Technical Summary

    Flow rate: 30,000 m³/h
    Industry: Pet food production
    Technology: PC-2 Two-stage packed column wet scrubber (acid stage + caustic-oxidative stage)
    Target pollutants: Amines, organic vapours, fatty acids, oil aerosols
    Process air characteristics: Emissions from extrusion, drying, coating and cooling phases

    Acid and caustic-oxidative stages designed around operational maintenance windows

    Air Pollution Control for Pet Food Production requires alignment between scrubber architecture and factory operating schedule.

    Air Pollution Control for Pet Food Production – two-stage packed column scrubber 30,000 m³/h
    Two-stage packed column scrubber installed for pet food air pollution control. Designed for 30,000 m³/h with maintenance-based operation strategy.

    Application context

    This Air Pollution and Odour Control system was designed to treat up to 30,000 m³/h of process air generated by a dry pet food production line operating on a single 8-hour shift.

    Air is extracted from the complete production cycle:

    • Extrusion
    • Drying
    • Coating
    • Cooling

    The emission profile includes:

    • Amines
    • Organic vapours
    • Fatty acids
    • Oil aerosols from coating phases

    Although airflow is relatively stable, contaminant concentration varies according to recipe formulation and coating intensity.

    Why a packed-only solution was selected

    Packed column scrubbers are often considered structurally limited in pet food applications because of oil mist deposition on the first stage packing.

    However, this limitation becomes critical only when production schedules do not allow regular maintenance.

    In this specific case, the production line operates on a single daily shift, providing predictable downtime. This makes it possible to:

    • Schedule periodic inspection
    • Perform cleaning when required
    • Manage progressive packing fouling as part of normal operation

    The engineering decision was therefore based on operational rhythm, not on catalogue standardisation.
    In this case, Air Pollution Control for Pet Food Production is based on predictable maintenance cycles rather than continuous elastic operation.

    System architecture

    The installed configuration consists of two separate packed columns, operating sequentially:

    First stage – Acid

    Designed to neutralise amines and stabilise odour load.

    Second stage – Caustic-oxidative scrubber

    Designed to complete neutralisation and improve robustness against residual organic compounds.

    The physical separation between stages allows:

    • Independent hydraulic and aeraulic control
    • Clear chemical segregation
    • Targeted maintenance planning

    This architecture remains structurally simple while ensuring staged treatment.

    This configuration was selected as a structured Air Pollution Control for Pet Food Production strategy aligned with the plant’s operating rhythm.

    Operational reality: fouling as a managed parameter

    In pet food production, oil aerosols generated during coating inevitably deposit on internal surfaces.

    In packed towers, the first stage becomes the primary deposition surface.

    Consequences over time may include:

    • Gradual pressure drop increase
    • Reduced mass transfer efficiency
    • Risk of channel formation
    • Foam generation

    In this installation, these effects are not treated as unexpected faults but as predictable phenomena integrated into the maintenance strategy.

    Because the factory does not operate continuously, the system remains viable and economically rational.

    Engineering positioning

    A two-stage packed column system can be an effective Air Pollution and Odour Control solution for pet food production up to 30,000 m³/h — provided that:

    • The plant does not operate continuously
    • Maintenance intervals are structurally available
    • Operational discipline is maintained

    Where these conditions exist, a packed-only architecture remains technically sound.

    Where production shifts increase or variability intensifies, reaction dynamics and fouling management require a different approach — which led to a more efficient evolution.

    When to choose a two-stage packed column scrubber

    Air Pollution Control for Pet Food Production can effectively rely on a two-stage packed column architecture when production operates on limited daily shifts and structured maintenance windows are available. In these conditions, oil mist deposition on the first stage packing can be managed through scheduled cleaning without compromising long-term stability. Where continuous three-shift production is required, reaction dynamics and fouling accumulation demand more elastic configurations.

  • | |

    Air Treatment System for Sludge Dryer Emissions – WWTP Application

    Technical Summary

    Application: Sludge drying
    Industrial sector: Wastewater treatment
    Air flow rate: 6,000 Nm³/h
    Air characteristics:     humid process air
    Main pollutants: H₂S, ammonia, sulfur compounds, VOCs
    Treatment lines: 2

    This sludge dryer odour control system is designed for wastewater treatment plants handling complex industrial emissions.

    Project Overview

    Sludge drying processes used in wastewater treatment plants generate complex gaseous emissions containing hydrogen sulfide, ammonia and various odorous organic compounds released during thermal treatment of sewage sludge.
    For the sludge drying units, two dedicated air treatment systems were engineered and installed to ensure reliable odour abatement.
    Each system was designed to treat process air extracted directly from the sludge dryer and combines multiple treatment stages to address the complex chemical composition of the emission stream.

    Engineering Challenges


    Air emissions generated by sludge dryers present several challenges for air pollution control systems:

    • variable pollutant composition
    • high humidity and condensable vapours
    • presence of aerosols and fine droplets
    • coexistence of sulfur compounds, nitrogen compounds, VOCs and dust

    These conditions require a multi-technology treatment approach, capable of handling different pollutant classes within the same emission stream.

    Sludge dryer odour control System Configuration

    Each treatment line integrates several sequential technologies.

    Venturi Scrubber + Packed Column

    The first treatment stage consists of a wet scrubber system composed of a Venturi section followed by a packed column.
    The Venturi section improves gas–liquid contact and promotes removal of dust and soluble compounds.
    The packed column increases gas–liquid contact time and allows efficient absorption of odorous pollutants.
    Main design parameters:

    • Air flow rate: 6,000 Nm³/h
    • Pressure drop: < 1,500 Pa
    • Contact time: 2 s
    • Column diameter: up to 2,000 mm
    • Column height: up to 7.5 m
    • Construction material: polypropylene
    industrial sludge dryer odour control system in wastewater treatment plant

    Biofiltration Stage

    Downstream of the chemical scrubber, the air stream is treated through a biofilter designed to biologically oxidize residual odorous compounds.
    The biofilter uses wood chips as filtering media, providing a suitable environment for microbial populations capable of degrading sulfur compounds.

    Main characteristics:

    • Filter media volume: 75 m³
    • Media type: wood chips
    • Moisture range: 55–85 %
    Biofiltration stage used for odour control of sludge dryer emissions in a wastewater treatment plant.

    Air Conditioning System

    To maintain optimal operating conditions for the biofilter, the system includes an air conditioning section with electric heating.
    This stage stabilizes temperature and humidity before biological treatment.

    Air conditioning stage installed upstream of the biofilter for treatment of sludge dryer emissions in a wastewater treatment plant.

    Activated Carbon Polishing Filters

    The final stage consists of activated carbon adsorption filters designed to remove trace pollutants remaining after biological treatment.
    Each filter contains approximately 2,500 kg of activated carbon, complemented by impregnated alumina for enhanced removal of sulfur compounds.

    Results

    The sludge dryer odour control system ensures stable performance and reliable odour abatement over time.

    The installed systems provide stable treatment of emissions generated by sludge drying operations, ensuring reliable odour abatement and compliance with environmental regulations.

    The integration of chemical scrubbing, biofiltration and adsorption allows progressive removal of pollutants with different chemical properties, increasing operational robustness.