Pet food production and animal by-products processing generate significant air emissions during thermal treatment, drying, fat separation and raw material handling. These emissions are typically characterised by strong odours, ammonia, organic vapours and aerosolised organic compounds generated during the processing of protein-rich materials.
The case studies presented in this category illustrate industrial air pollution and odour control systems designed specifically for pet food manufacturing plants and rendering facilities processing Category 3 animal by-products. Each project highlights how emission treatment systems must be engineered around the specific process conditions that generate these emissions.
Flow rate: 8,000 m³/h
Industry: Animal by-product ABP transformation
Technology: 1 Acidic + 1 Alkali/oxidative PC-1 single staged scrubbers
Target pollutans: Odour, ammonia, VOC
Process air temperature: 80°C
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
Air Pollution Control for Pet Food Production requires alignment between scrubber architecture and factory operating schedule.
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:
The emission profile includes:
Although airflow is relatively stable, contaminant concentration varies according to recipe formulation and coating intensity.
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:
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.
The installed configuration consists of two separate packed columns, operating sequentially:
Designed to neutralise amines and stabilise odour load.
Designed to complete neutralisation and improve robustness against residual organic compounds.
The physical separation between stages allows:
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.
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:
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.
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:
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.
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.
Flow rate: 120,000 m³/h (two parallel lines, 60,000 m³/h each)
Industry: Pet food production
Technology: Variable-throat Venturi scrubber + downstream wet scrubbing stages
Target pollutants: Organic vapours, fatty acids, amines, oil aerosols
Process air sources: Extrusion, drying, coating and cooling
Air Pollution and Odour Control in Pet Food Production requires full integration with thermal processes, airflow stability, and emission variability management.
This case study concerns the design of an Air Pollution and Odour Control in Pet Food Production plant, with a total extracted air flow rate of approximately 120,000 m³/h.
The production process includes:
Air emissions are characterised by:
In pet food production, emission profiles are not constant. Raw material composition and coating formulations significantly influence contaminant concentration and aerosol load.
For this reason, air pollution control in pet food plants cannot be designed based on nominal flow rate alone.
The odour control system had to be integrated without disturbing:
Any unstable downstream pressure condition would have:
In pet food production, maintaining thermal stability is directly linked to product performance and energy efficiency.
The air pollution control system therefore had to adapt to the production process — never the opposite.
Given the fluctuating contaminant load and presence of oil aerosols, a Venturi scrubber with variable throat section was selected as the primary stage of the odour control system.
The Venturi operates on inertial impaction principles: particle and aerosol removal efficiency is directly related to gas velocity and pressure drop (ΔP).
The variable throat configuration allows:
Unlike fixed-throat systems, the variable geometry maintains the required impact energy while adapting to process variability typical of pet food air emissions.
The Venturi stage was dimensioned based on required separation efficiency, not solely on nominal air flow rate.
A key design principle of this Air Pollution and Odour Control system was that downstream fans must never interfere with the process fans of the oven.
The tail-end extraction fans were installed downstream of the treatment plant and equipped with variable frequency drives (VFD).
Their function is to:
This ensures that:
The odour control system behaves as a controlled hydraulic load, not as an active disturbance to the production process.
In Venturi scrubbers, separation efficiency is directly related to gas velocity and pressure drop. Reducing ΔP in order to minimise energy consumption without understanding the required impact energy inevitably compromises particle and aerosol removal efficiency.
In this application, the variable throat configuration allows optimisation of ΔP according to real operating conditions, ensuring stable performance without unnecessary energy penalties.
Maintaining stable oven conditions in pet food production results in:
The air pollution control system therefore contributes not only to emission abatement, but also indirectly to energy optimisation and process reliability.
In dry pet food production, effective Air Pollution and Odour Control requires full integration with process airflow and thermal dynamics.
Designing only for flow rate leads to instability.
Designing for:
ensures predictable performance.
Air pollution control in pet food production is not an add-on system.
It is a process-integrated engineering solution.
