How to Manage Odour in Pet Food Manufacturing: Proven Technologies & Regulatory Insights

Introduction

The pet food manufacturing industry has grown significantly in recent years, driven by increasing pet ownership and demand for high-quality, specialized pet nutrition. However, one of the persistent challenges in this sector is managing odours generated during production. The processing of animal proteins, fats, and other organic materials creates volatile organic compounds (VOCs), sulfur compounds, and amines, which produce strong, often unpleasant odours. These odours can affect worker safety, community relations, and regulatory compliance. Effective odour control is thus critical for operational success, environmental responsibility, and maintaining a positive public image.

This article explores the sources of odours in pet food manufacturing, their impact, and the technologies and strategies available for effective odour management. It also examines Regulations, industry best practices, and emerging innovations, providing a comprehensive guide for manufacturers seeking to mitigate odour-related challenges.

What Causes Odours in Pet Food Manufacturing?

Pet food manufacturing involves several processes that contribute to odour emissions, including raw material handling, cooking, extrusion, drying, and packaging. Understanding these sources is the first step in designing effective control measures.

1. Raw Material Handling

Pet food production often begins with the receipt and storage of raw materials such as meat, fish, poultry by-products, grains, and fats. These materials, particularly animal-based ingredients, can emit odours during unloading, storage, and preprocessing. Decomposition of organic matter, especially if storage conditions are suboptimal, exacerbates the issue.

2. Batching and Grinding

The raw materials or all the ingredients defined based on the formulation of the company, including protein sources such as fishmeal, chicken-meal etc. are grinded along with the other materials. During this time there will be VOC and dust generation, which will be handled in a bag filter. The dust gets trapped in the bag filter but the exhaust air after the bag filter will be having VOCs and that causes odour emission from the process.

3. Cooking

A key process in which animal by-products are cooked at high temperatures (often exceeding 120°C), leading to the release of VOCs, including aldehydes, ketones, and sulfur-containing compounds like hydrogen sulfide (H₂S). These compounds have low odour thresholds, meaning even small concentrations are detectable and potentially offensive.

4. Extrusion and Drying

Extrusion involves mixing, cooking, and shaping pet food under high pressure and temperature. The process releases steam and volatile compounds, contributing to odour emissions. Drying, used to reduce moisture content in kibble or treats, further volatilizes organic compounds, releasing them into the exhaust air.

5. Packaging and Storage

While less intense, odours can also arise during packaging if residual volatile compounds are released from freshly processed products. Improperly sealed storage areas may allow odours to escape into the surrounding environment.

Why Odour Control Matters in the Pet Food Industry

Odour emissions from pet food manufacturing have wide-ranging implications:

Given these impacts, effective odour control is not just a technical necessity but a strategic priority for pet food manufacturers.

Regulations Governing Odour Emissions

Odour regulations vary by region but generally aim to limit nuisance and protect air quality. In the United States, the Environmental Protection Agency (EPA) and state-level agencies enforce standards under the Clean Air Act, which may include limits on VOCs and hazardous air pollutants (HAPs). Facilities must also comply with local zoning laws and nuisance ordinances.

In the European Union, the Industrial Emissions Directive (2010/75/EU) sets guidelines for managing emissions, including odours, from industrial processes. Member states often have additional requirements, such as Germany’s Technical Instructions on Air Quality Control (TA Luft), which specify odour thresholds.

In Australia, the Environmental Protection Authority (EPA) in each state regulates odour emissions, often requiring facilities to conduct odour impact assessments and implement control measures. Similar frameworks exist in Canada, where provincial governments oversee compliance.

Pet food manufacturers must stay informed about applicable regulations and engage with regulatory bodies to ensure compliance. This often involves monitoring emissions, modeling odour dispersion, and reporting to authorities.

Top Odour Control Technologies for Pet Food Manufacturing

A range of technologies is available to control odours in pet food manufacturing, each suited to specific processes and compounds. These can be broadly categorized into physical, chemical, and biological methods, often used in combination for optimal results.

1. Physical Methods

2. Chemical Methods

3. Biological Methods

Best Practices for Pet Food Manufacturing Odour Management

Beyond installing control technologies, pet food manufacturers can adopt operational and strategic practices to minimize odours:

1. Process Optimization

2. Facility Design

3. Monitoring and Modeling

4. Community Engagement

5. Training and Maintenance

Elixir Enviro Systems – Experts in Pet Food Odour Control

If you’re looking for reliable pet food odour control, Elixir Enviro Systems is your trusted partner. We specialize in industrial odour treatment, wastewater management, and biofiltration systems for factories and processing plants.

With years of experience, Elixir offers complete solutions—from design and installation to testing and maintenance. Whether your facility needs scrubbers, biofilters, RTOs, or real-time odour monitoring, we’ve got you covered.

Why Choose Elixir Enviro?

✅ Pioneer in Industrial Odour Control in India

✅ Largest player in India having treating about 1 Million cubic meter of air each hour

✅ Experts in pet food manufacturing odour control

✅ Custom solutions for industrial odour problems

✅ In-house R&D and simulation tools

✅ Onsite odour audits and pilot testing

✅ Solutions that meet all local and global regulations

Visit www.elixirenviro.in to learn more or contact us for a custom consultation on odour control for your facility.

Conclusion

Odour control in the pet food manufacturing industry is a multifaceted challenge requiring a combination of advanced technologies, operational best practices, and community engagement. By understanding the sources of odours—raw materials, batching-Grinding, extrusion, and wastewater—manufacturers can deploy targeted solutions like scrubbers, biofilters, and oxidizers. Regulatory compliance, worker safety, and environmental sustainability further underscore the importance of effective odour management.

As industry continues to grow, so too will the need for innovative, cost-effective, and eco-friendly odour control strategies. Manufacturers that invest in these solutions will not only mitigate risks but also strengthen their reputation as responsible corporate citizens. By prioritizing odour control, the pet food industry can ensure a harmonious coexistence with communities and a sustainable future for pet nutrition.

📌 FAQ Section

Q1. What causes odour in pet food manufacturing?

A: Odours are primarily caused by raw material handling, grinding & batching of ingredients, extrusion, drying, and improper wastewater management. These processes release VOCs, sulfur compounds, and amines.

Q2. How can odour emissions be controlled in pet food factories?

A: Odour control can be achieved using technologies like biofilters, wet scrubbers, regenerative thermal oxidizers (RTOs), and proper ventilation systems. Process optimization and regular maintenance also play a crucial role.

Q3. Are odour control systems mandatory for pet food manufacturers?

A: In many regions, yes. Regulatory bodies like the US EPA, EU’s Industrial Emissions Directive, and local environmental agencies require odour emissions to be controlled and monitored. Other locations around the globe mostly have nuisance law, meaning if the neighborhood complains, the factory might need to shut down until the issue is rectified. Considering this, the cost of installation of the Odour Control Unit surpasses the disadvantages of legal penalties, factory-closures and poor neighborhood relationships.

Q5. What role does Elixir Enviro Systems play in odour control?

A: Elixir Enviro Systems offers turnkey odour control solutions tailored to pet food manufacturing, including biofilters, scrubbers, oxidizers, and real-time monitoring. They also provide audits and pilot testing to ensure effectiveness.

Biological Odour Control – What is it?

Introduction

Last March, residents of Sector 28 Vashi, Navi Mumbai complained of a toxic smell from the local industrial area. The people said that the chemical manufacturers in the neighbouring Trans Thane Creek (TTC) industrial region are the source of the toxic smell. They complained that the toxic smell caused severe discomfort affecting their health and caused contamination of water (Free Press Journal- 8th March 2024) 

For many years, residents of Ivy City, Northeast Washington complained of a burning stench in this area. It is only recently that they were able to find the reason behind this. Environmentalists, community activists and residents have concluded that the stench is mainly because of a manufacturing facility- National Engineering Products(NEP) Inc. that makes a sealant for the Navy, using chemicals such as formaldehyde, acetonitrile and methylene chloride. Community activists and environment activists, along with neighbours, worry that NEP’s emissions could endanger nearby families(The Washington Post- 11th April 2024). 

The problems caused by Industrial odours are not just limited to India but affect the whole world. Industrial odours arise as a result of industrial processes that release different compounds as byproducts. In low concentrations, these compounds may cause discomfort, nausea, sleeplessness and physiological disturbances but at high concentrations, they can cause severe problems including respiratory diseases, increased stress and altered blood flow in the lungs. Thus, the source of these problems must be identified and steps taken to mitigate its release to the atmosphere. This improves health and ensures the overall well-being of the people.

It is observed that industrial odours mainly arise from industries and factories because of the compounds that are released into the environment. Industrial odour is mainly controlled by physical, chemical and biological methods of which the biological method is most significant, mainly due to the sustainability, low cost and feasibility of conducting at moderate temperatures and pressures. The most prominent Biological methods for odour control include use of biofilters, bioscrubbers and biotrickling filters. 

 

Odour Generating Industries

Industrial odour are generated by variety of organisations, industries and facilities. It includes

  1.  Food & Feed Processing Industries: Cocoa processing, Coffee processing, Fish Processing, Bone meal industry, Slaughterhouses – rendering plants,  Spices & bio-ingredient extraction units, Sugar manufacturing, Brewery & distillery, acetic acid fumes from bottle cleaning stations, oil mills,  feed manufacturing units (fish feed, shrimp feed, pet feed, cattle feed etc) and Livestock operations 
  2. Automobile and allied Industries: It also includes foundries, manufacturing of tires, tire/rubber reclaim factories, latex/rubber processing, rubber thread manufacturing units, caprolactam manufacturing, paint manufacturing, metal pickling plants, 
  3. Other industries: Petroleum refinery, Pulp and paper, Sugar and distillery, Chemical dye and & dye intermediates, Pharmaceuticals & bulk drugs, Teflon cookware manufacturing, Plastic product manufacturing, printing, tanneries, Gelatin manufacturing, Solvent manufacturing and processing, Tobacco Processing and Other Chemical Industries. 
  4. Infrastructure Development: Ceramic production, Plywood manufacturing units, Bitumen Processing units, Wood Processing units Waste Transfer Stations, Treatment plants (Incineration plants, Pyrolysis units, Waste-to-Energy plants, Composting plants, Anaerobic Digestion Plants, Biodrying units), Wastewater lifting/Pumping Stations, and Wastewater Treatment Plants (Sewage Treatment Plants – STP and Effluent Treatment Plants- ETP).

In Ireland in 2023, 90% of the complaints made to EPA (Environmental Protection Agency) were due to noise and odour from various industries like food, recycling, creameries and waste disposal. The Kerala State Pollution Control Board (KSPCB) commissioned a study on the odour pollution-related issues at Edayar Industrial Area in September 2022. The study was done by the CSIR-National Institute for Interdisciplinary Science and Technology (NIIST), Trivandrum on behalf of KSPCB. The study found several deficiencies in the operation of odour control units installed in nearly 20 bonemeal units, chicken waste rendering plans and rubber processing units in the Edayar industrial area. 

Causes

Odour from industrial establishments is caused by the chemicals present in the exhaust gas. There are many chemicals responsible for the odorous compounds. Hydrogen sulphide, Sulphur dioxide/ trioxide, nitrogen oxides, ozone, ammonia, volatile fatty acids (eg butyric acid), aldehydes and ketones (eg formaldehyde), mercaptans, amines and alcohols contribute majorly to the odour generated. These chemicals are majorly generated by various industries. 

Hydrogen sulphide is a gas with a rotten egg smell. It is detectable at very low concentrations. It is colourless and found in many cleaning products, and animal waste and is a byproduct of several industrial processes like oil refining, mining, craft paper production, rayon manufacturing, food processing, wood pulp processing and tanning. People living near these kinds of industries are most exposed to hydrogen sulphide. 

Ammonia and ammonium compounds are also major contributors to Industrial odour. It mainly arises from large-scale animal feed manufacturing, municipal waste treatment plants operations (generally as the byproduct of protein degradation), production of fertilizers, pharmaceutical production and food processing operations. Known for its pungent and piercing smell, ammonia (NH3) is frequently present in animal faeces and a variety of cleaning products. 

Nitrogen oxides are mixture of gases composed of oxygen and nitrogen. The most significant of them include nitric oxide, nitrogen dioxide, nitrogen monoxide and nitrogen pentoxide. Oxides are nitrogen are mostly used in the manufacture of fertilizers, explosives, mining and from wastewater treatment plants. Facilities that use welding materials produce nitric acid or certain explosives and workers employed in such facilities inhale oxides of nitrogen.

Sulphur dioxide is colourless with a sharp and pungent odour and is produced by industrial processes like fertilizer manufacturing, steel making, aluminium smelting, ceramic manufacturing and combustion of fossil fuels. 

VOC (volatile organic compounds) are another major source of odour and air pollution. The major contributors are the petrochemical industries, paint manufacturing, pharmaceutical and bulk drug manufacturing industries, chemical industries, rubber processing industries etc. A sub-category under the VOCs are the Volatile Fatty Acids (VFA) like butyric acid, acetic acid and propionic acid also contribute to industrial odours. Such acids are mainly generated during fermentation processes, dairy products as well as in the decomposition of fats and oils. One source of VFAs are through anaerobic degradation of organic materials. 

 

Effects

The effects of hydrogen sulphide depend on the concentration as concentrations higher than 150 ppm can paralyse the olfactory nerve and higher than 200 ppm can be life-threatening. People with asthma may be sensitive even to its low concentrations. High H2S concentrations can induce nausea, headaches, and dizziness through inhalation. Even greater exposure levels have the potential to cause unconsciousness, coma, or respiratory arrest. There have been fatal exposures lasting 30 minutes at doses higher than 600 ppm. Severe exposures that do not cause death could result in long-term consequences such as damage to nerve tissue, paralysis of the facial muscles, or memory loss.

Sulphur dioxide has been linked to cardiovascular diseases and may cause respiratory problems like bronchitis, wheezing, phlegm and asthma attacks. Chromosome abnormalities and sister chromatid exchanges were noted in lymphocytes from workers exposed to 15.92 ppm sulfur dioxide at a fertilizer company in India. Aldehydes and ketones can irritate the eyes, nose, and throat. They can also occasionally have harmful effects on the nervous system.

Ammonia inhalation can lead to respiratory issues, skin and eye irritation, and in extreme situations, lung damage. Oxides of nitrogen can irritate eyes, nose throat and lungs at low levels. Higher exposure can result in the buildup of fluid in the lungs. Inhaling high levels of nitrogen oxides can lead to spasms, swelling of tissues in the throat, burning and even death. 

Exposure to the VOCs can cause a ripple effect in the health of human being, Starting from eye, throat and nose irritation to headache and loss of coordination that may extend to damage of liver, kidneys and even the central nervous system. Some of the VOC compounds are known for its carcinogenic properties.  Skin and mucous membrane discomfort may result from exposure to volatile fatty acids. These acids have the potential to negatively impact both aquatic and terrestrial creatures by contributing to air and water pollution.

Managing Industrial Odours

Industrial odours is a major cause of complaint and discomfort for people. Owing to its importance in the current age and time, proper management of odour and air emissions from any industry is of utmost importance.. Industrial odours and emissions can be controlled by either physical, chemical or biological means. Physical methods include containment methods such as odour covers, dilution methods like stacks, and site planning. 

There are several chemical methods to control industrial odour. Over time many chemical formulas have been developed to treat those compounds generated by industrial processes. The chemical odour control methods include additives “claiming to neutralize the odour”, masking agent (sprays), adsorbents, ozone(ozonation), ultraviolet treatment and catalytic oxidation.

Compared to physical or chemical means, biological order control methods rely solely on bacteria and other microorganisms. These techniques include use of biofilters, bioscrubbers, biotrickling filters, and other bioreactor types. Use of these methods have been reported to be more environmentally friendly and less expensive than physical or chemical methods. It can also be conducted at normal temperatures and is simple to operate. The process is also ecologically clean as the end products are ecologically safe and oxidative in nature. Researches have shown that biological treatment methods can be considered as robust and reliable alternatives to physical or chemical treatment methods.

 

Biofilters

These are one of the oldest biotechnological odour pollution control techniques used to remove undesired compounds from air. They immobilise microorganisms on a solid support. Biofilters or generally used for removing hydrogen sulphide, VOCs, nitrous oxide, sulphur gases, etc. Use of biofilters can be traced back to 1920s when they were used to remove compounds emitted from animal farms and waste treatment plants. Countries like Germany and Netherlands have used this technology since the 1970s and it became popular in Western Europe and the United States in the 1980s. Europe and Japan have reported the most success in this technology. 

Biofilters may be open biofilters or closed biofilters. In open biofilters, the upper part of the bioreactors is open making it more exposed to climate change whereas in closed biofilters parameters such as temperature, fluid composition and fluid flow are easier to monitor and control. The biofilters can also be classified into upflow and downflow biofilters based on the airflow through the media – if the airflow is going from top to bottom of the media, its called downflow biofilter whereas the opposite is called the upflow biofilter. The later is the common practice due to cost constraints mainly.

General Arrangement of a Biofilter System

 

The processes happening in the Biofilter are as follows: Initially, the pollutants are transferred from gas to liquid phase and then subjected to biodegradation by the biofilm. Bacteria constitute chunk of the microorganisms found in the biofilm. Among the bacteria, coryneforms, endospore formers (eg bacilli), pseudomonads and streptomyces are mainly used. The use of bacteria as the best candidate for use in biofilms have been after extensive research: types of microorganisms and their metabolic activities, isolation and characterization, the use of pure cultures, mixed microbial populations, effect of culture enrichment including application of specific strains and effects of external conditions on microbial activity. 

Biofilters are fixed-bed bioreactors. During this operation, pollutants pass through a media bed in which active microorganisms are immobilized. This media bed causes the degradation of pollutants by biological oxidation. Good water retention capacity, presence of a dense and diverse microflora, large specific surface area, high porosity and intrinsic nutrients are some of the important requirements considered for making the media bed. The media bed is the region where the microorganism thrives and should be able to satisfy these conditions Organic materials are generally used for the preparation of bed media as these materials satisfy the requirements and are readily available at low cost. The contaminants that settle on the media bed constitute the nutrition for the biofilm by degradation. These microorganisms are generally neutrophilic, aerobic and mesophilic. Optimum moisture content is also important to ensure the survival of the biofilm ensuring that the moisture content is not too high or too low. 35- 40% of moisture is adequate for the biofilm. Pressure drop is also an important parameter and varies with the material that is used.

Biofilters are very useful and have been reported to remove many contaminants like hydrogen sulphide, dimethyl sulphide, ammonia, sulphur-containing gases and methanethiol. These are some of the common contaminants seen in wastewater treatment facilities, food waste and composting operations.

 Schematic representation of biofilter

 

Bioscrubber 

Bioscrubber is an odour treatment method said to be a combination of a gas scrubber and a biological reactor. In this process physical separation or absorption of odors in the liquid phase occurs in the gas scrubber and the biological treatment occurs in the bioreactor. The liquid leaving the bioreactor (effluent) is recirculated to the top of the column. This facilitates efficient gas cleaning of highly soluble pollutants.

Bioscrubber

Pollutants in the air stream are removed through the bioscrubbers in the following ways: adsorption, absorption, condensation and biodegradation. It is generally preferred to use packed tower absorbers for bioscrubbers as others (wet cyclone, spray tower and venturi scrubber) show poor elimination efficiency for compounds with poor solubility in water. Generally, resistance to corrosion caused by gases and liquids, resistance to UV and thermal and mechanical resistance against temperatures are all considered while designing an absorption tower. The pollutant absorbed liquor from the scrubber undergoes continuous aeration in the bioreactor, and the active microbial culture converts the pollutant into CO2, H2O, and biomass.

The “lean” water, or bioreactor effluent, is cycled back to the absorber and used again. Bioreactors for bioscrubbing work on similar principles to activated sludge tanks used in wastewater treatment systems in terms of both design and operation. The primary distinction is that with bioscrubbing, the hydraulic retention period is typically significantly longer and equal to the sludge retention time. For this reason, bioscrubbers do not need sludge retention/separation facilities. The majority of bioscrubbers on the market today are made to remove just one type of pollutant. To give additional efficient odour management, increased operating flexibility, and other advancements in traditional designs of bioscrubbers have been examined, including the sorptive-slurry bioscrubber and the anoxic bioscrubber, airlift bioscrubber, spray column bioscrubber, two-liquid phase bioscrubber, or two-stage bioscrubber

A counter current packed tower is considered over a co-current or cross-flow towers owing to its lower pressure drop, lower energy costs and higher absorption efficiency. The ability of the bioscrubber to produce and sustain significantly larger volumes of microbial biomass in fewer process units, while retaining very high specific substrate utilization rates, is a considerable advantage over a typical biofilter and biotrickling filter. The bioreactor can be started by inoculation with activated sludge from a wastewater treatment facility and by microbial development. It relies on environmental factors like temperature, ionic strength, pH, and the presence of hazardous substances and substrate concentration. Bioscrubbers are generally used to remove ammonia, odours from wastewater treatment plants and hydrogen sulfide. The bioscrubber system is particularly advantageous when there is a good wastewater treatment plant available, thereby the load from the bioscrubber can be handled in the wastewater treatment plant and also the additional inventories such as blowers and tanks can be avoided.

Schematic diagram of bioscrubber

 

Biotrickling filters 

This is a recent technology using more sophisticated biological waste gas treatment  equipment. Like biofilters, it uses microorganisms fixed on a media and aqueous solution containing essential nutrients is trickled over the filter bed. The microorganisms grow as a biofilm and as the solution reaches the biofilm, it degrades it. The filter beds are usually made of an inert material (natural or synthetic) such as open pore synthetic foam, dump plastic packing and structure plastic packing. Other materials that have been used are TDRP (Tire-derived rubber particle), glass, ceramics and lava rock. Like biofiltration this method is simple and of low cost and is quite effective removing up to 90% of volatile organic compounds (VOCs). It is also effective for removing nitrogen components, chlorine laden components and sulphur compounds. But require sophisticated control system and continuous monitoring and makeup of nutrients to ensure the adequacy of the treatment. 

Biotrickling filters are a combination of biofilters and bioscrubbers in which bacteria are immobilized on a carrier or filter material. The filter bed must be always covered with water meaning water must be uniformly sprayed. The contaminants are absorbed and decomposed by the biofilm. The circulating liquid must be checked for its nutrients (serve as feed for biofilm), pH and salt concentration. Here gas which is irrigated with an aqueous solution containing essential nutrients is carried through the filter bed. The flow of gas can be in the co-current or counter-current mechanism. Some studies suggest that co-current is better. Most of the contaminants are degraded by the biofilm. The extent of action by the filter bed depends on the activity of the microorganisms present. The filter bed will be home to a large cluster of microorganisms- aerobic and anoxic. The primary degraders constitute only a small fraction and a much larger fraction is occupied by the secondary degraders like bacteria, yeasts, fungi, and protozoa. The secondary degraders play a noteworthy role in reducing rate of biomass accumulation and recycling inorganic nutrients. Biotrickling filters are operated in temperature range of 10-40 ℃ which is the best temperature for the growth of mesophilic organisms. They are generally used to remove contaminants like hydrogen sulphide, ammonia and methanethiol.

Schematic diagram of biotrickling filter

 

 

Conclusion

Industrial odours are a major problem. The primary cause of industrial odour pollution is the airborne presence of volatile chemicals that are transported with the wind. Odorous compounds are typically volatile, corrosive and irritating, even at very low concentrations, and cause odour nuisance due to their low odour thresholds. Measurement of odour is very important and this is done by various methods like Indicator tubes, Dynamic olfactometry, Gas chromatography and electronic noses. Numerous physical-chemical and biological odour control systems have been documented in the literature to reduce the annoyance of odours emanating from the industries. The advantages of biological procedures over other methods are their efficacy, affordability, chemical-free operation, and environmental friendliness. Biological methods include use of biofilters, bioscrubbers and biotrickling filters. The biological methods are being further developed promising a remarkable future for controlling industrial odours.