Sustainable Rendering for a Circular Economy: Odour Control in Rendering Plants as a Pathway to ESG Excellence

Industrial rendering plants across India and the globe face one major environmental challenge — odour. Effective odour control in rendering plants is crucial not only for environmental compliance but also for community wellbeing and sustainable industrial growth. The rendering industry plays a crucial role in protecting the environment. Generally, a rendering plant collects animal byproducts such as offal, fat, bones and carcasses from animal slaughterhouses, butcher shops, supermarkets (markets) and farms and turn them into usable materials like tallow, grease and bonemeal. These materials are then used for the manufacturing of a variety of products soaps, animal feed (including pet-feed) and some industrial items.  Yet, it carries one unavoidable challenge — odour & high strength wastewater. In this blog we would like to cover, how to handle the pungent, persistent smell from rendering operations, which is one of the most complex environmental issues industries face today. Odour emissions are not merely an inconvenience; they directly influence community relations, regulatory compliance, and the public image of the company. For progressive industries, this challenge has become a defining factor in their sustainability and ESG (Environmental, Social, and Governance) strategies.

At the forefront of this transformation are modern engineering solutions like those deployed by Elixir Enviro Systems that combine science, environmental responsibility, and innovation to create cleaner, more sustainable air treatment systems for rendering plants.

Where Does Odour Come from in Rendering Plants?

To control odour effectively, one must first understand its origin. Rendering plants handle raw animal materials such as offal, blood, bones, feathers, and fat residues. During processing, cooking, drying, and pressing, these organic materials decompose, releasing volatile organic compounds (VOCs), hydrogen sulfide (H₂S), ammonia, mercaptans, and amines. These compounds are potent even in low concentrations. For instance, hydrogen sulfide is noticeable at just a few parts per billion and produces a strong “rotten egg” smell, while mercaptans smell even stronger and are often detected far from the source. Uncontrolled odour can travel over large distances, affecting nearby communities, attracting complaints, and even halting production due to environmental violations. Hence, rendering plants increasingly rely on engineered odour control systems designed to target these compounds through physical, chemical, and biological means.

Why Odour Control Matters Beyond Compliance

The modern rendering industry is evolving. Regulations now demand comprehensive environmental management systems that align with ESG and sustainability commitments. Odour control has become a key ESG indicator because it reflects a plant’s environmental responsibility, social accountability, and operational transparency.

A robust odour control strategy brings measurable advantages:

  1. Regulatory compliance with pollution control boards(regulatory agencies) and environmental agencies
  2. Improved community relations by reducing complaints and promoting goodwill
  3. Enhanced workplace safety through improved air quality
  4. Stronger ESG reporting that aligns with global sustainability frameworks
  5. Better brand reputation, as odour-free operations symbolize responsible industry practices

Companies like Elixir Enviro Systems have recognized that odour control isn’t just an environmental requirement — it’s an operational necessity and a reputational advantage.

Engineering the Air: How Rendering Plants Can Achieve Effective Odour Control?

Odour control in rendering plants is a multi-layered process that requires understanding of airflow patterns, pollutant chemistry, and microbial treatment. Below are the most effective engineering strategies used globally — adapted and optimized for Indian and international industries by Elixir Enviro Systems.

1. Capture and Containment

The first step in managing odour is preventing its escape. This involves designing airtight a good ventilation systems to capture emissions from:

  1. Cookers and dryers
  2. Pressing and decanting units
  3. Fat and meal storage tanks
  4. Blood drying systems

A proper ventilation system ensures that all air carrying odourous compounds is directed to a centralized treatment unit instead of being released into the atmosphere. This not only minimizes fugitive emissions but also improves the efficiency of odour control technologies.

2. Chemical Scrubbing Systems

Scrubbers are among the most reliable methods for treating high-intensity odour streams. In these systems, acidic or alkaline solutions are used to neutralize gases such as the alkaline odourous compounds like ammonia, & the acidic odourous compounds like hydrogen sulfide.

Elixir’s engineered scrubber designs optimize contact time and chemical efficiency, ensuring minimal chemical consumption with maximum odour removal. Multi-stage scrubbers are often used to treat mixed compounds, for instance, an acid scrubber followed by an oxidizing scrubber for complete neutralization.

3. Biological Odour Control Units

Biological systems utilize microorganisms to naturally degrade odourous gases into harmless compounds such as carbon dioxide and water. They are sustainable, cost-effective, and energy-efficient solutions for continuous odour control.

Biofilters:

Biofilters use organic or synthetic media to absorb and biologically degrade VOCs, ammonia, and H₂S. They achieve 85–95% odour removal efficiency and are ideal for air from enclosed conveyors, pits, and dryers. Regular media maintenance ensures consistent performance.

Biotrickling Filters:

These systems use synthetic packing material continuously irrigated with nutrient-rich water, supporting microbial activity for odour degradation. They achieve 90–98% efficiency and are suitable for high-concentration ammonia and H₂S streams, though they require controlled water and nutrient supply.

Bioscrubbers:

In bioscrubbers, odourous air passes through a liquid medium containing active microorganisms that degrade water-soluble pollutants. They achieve 80–90% efficiency, ideal for ammonia-rich odours, but require additional water treatment and energy for recirculation.

4. Thermal and Catalytic Oxidation

For rendering facilities with very high VOC loads, thermal oxidation or catalytic oxidation provides complete destruction of odourous gases. These systems operate by heating the contaminated air to high temperatures, breaking down volatile compounds into simple molecules like CO₂ and H₂O.

5. Activated Carbon Filtration

In specific sections such as product handling areas or packaging zones, activated carbon filters are used to polish residual odours. The porous carbon material adsorbs remaining organic compounds, ensuring the final discharge is nearly odourless. These systems complement biofilters and scrubbers, creating a multi-barrier odour treatment process. Activated carbon filters work as adsorption media, and therefore generally the carbon units are not recommended for high odour emission industries such as the rendering plants.

6. Plasma Technology:

Emerging non-thermal plasma systems use high-energy electrons to break down odourous molecules at 85–95% efficiency. They are compact and efficient for many contaminants. But not have seen any case study or related document showing use case in the rendering industry.  but involve higher operational and maintenance costs due to electrode replacement requirements.

7. Combination Treatments for Odour Control

In many cases, combining technologies improves overall efficiency and ensures comprehensive odour removal across multiple sources.

Common hybrid systems include:

Chemical Scrubber + Biofilter:

The pretreatment with chemical scrubbers followed by the Biofilter for polishing seems ideal choice for the Odour Control from the Rendering plants.  This combination can ensure the air for total efficiency up to 99%.

Thermal Oxidation + Biofilter:

Used in facilities with separate odour streams, where intense odours are treated thermally and moderate ones biologically, balancing cost and performance.

Biofilter + Activated Carbon Filter:

Biofilter removes major odorous gases (85–95%), and activated carbon filters polish the air for total efficiency up to 99% — ideal for reception pits and enclosed areas.

Chemical Scrubber + Biotrickling Filter:

This pairing achieves up to 95–98% total efficiency, handling mixed acid and alkaline gases effectively in high-odour-load plants.

Chemical Scrubber + Activated Carbon Filter:

Scrubbers neutralize H₂S and ammonia, while carbon filters remove VOCs — giving 95–99% efficiency, ideal for plants with multiple odour sources.

 

Though biological odour control units are very efficient, the use of biological systems alone for rendering plants is not advisable. As the load is very high from the rendering plants, the biological treatment units shall take up a very large floor space. Hence in the case of rendering plants it is always better to have a combination treatment.  These hybrid systems are customized based on air volume, odour type, and emission intensity, ensuring optimized cost and performance for every rendering plant.

Integrating Wastewater and Air Odour Control

Apart from the challenges of having high strength wastewater, the wastewater treatment plants in Rendering plants also can release secondary odour during collection and treatment. By integrating wastewater treatment with air odour management, facilities can prevent odour migration from open tanks, sludge drying beds, and effluent channels.

Elixir’s integrated design approach combines:

  1. Covered tanks and pipelines to limit volatilization
  2. Anaerobic digesters for biogas capture and reduction of load
  3. High rate Biological Nutrient Removal (BNR) plants to remove both COD and nutrients
  4. Odour scrubbers for headspace gases

This holistic design ensures consistent odour control throughout the plant, maintaining compliance and environmental integrity. The details of the wastewater treatment maybe discussed in a separate blog.

Odour Control Regulations and Standards

In India, the Central Pollution Control Board (CPCB) and respective State Pollution Control Boards (SPCBs) set strict emission standards for rendering operations under the Air (Prevention and Control of Pollution) Act, 1981, but at present the CPCB doesn’t give specific regulation on Odour control in India.

Globally, regulatory bodies such as the U.S. Environmental Protection Agency (EPA) and the European Union’s Industrial Emissions Directive (IED) also enforce odour and air quality standards for animal by-product processing facilities.

Elixir Enviro Systems ensures that every system — from scrubbers to biofilters — is designed to meet or exceed these emission norms, helping clients maintain environmental compliance both in India and worldwide

Smart Monitoring and Modelling: The Future of Odour Management

Modern odour control goes beyond physical systems — it now integrates real-time data, digital simulations, and predictive monitoring for better performance and compliance. Elixir Enviro Systems utilizes advanced odour dispersion modelling to predict and assess odour behaviour under varying operating conditions. This enables engineers to optimize air capture points, ventilation strategies, and treatment system capacity with greater accuracy. Onsite odour monitoring units continuously measure parameters such as hydrogen sulphide (H₂S) and ammonia concentrations, allowing proactive intervention before odour complaints or threshold exceedances occur. This data-driven approach enhances transparency and supports ESG (Environmental, Social, and Governance) reporting by providing measurable, verifiable environmental performance indicators.

ESG in Action: How Odour Control Reflects Environmental Commitment

Rendering facilities are now integral to circular economy models, transforming waste into value. But to remain sustainable, they must operate within the boundaries of environmental stewardship. Odour control is one of the most visible reflections of ESG compliance. It demonstrates commitment to:

  1. Environmental goals: reducing emissions and protecting air quality.
  2. Social responsibility: improving community health and relations.
  3. Governance: maintaining transparent, data-backed environmental performance.

Elixir Enviro Systems  aligns its technologies with these ESG pillars, helping industries not only meet legal standards but also exceed them — turning odour control into an opportunity for sustainable growth.

Elixir Enviro Systems: Delivering Advanced Odour Control Solutions for Rendering Plants

Elixir Enviro Systems is a leading provider of industrial odour control solutions for the rendering industry, helping facilities eliminate nuisance emissions and meet the highest environmental standards. With decades of expertise in air treatment, wastewater management, and environmental engineering, we deliver custom-built systems that ensure cleaner air and sustainable operations. Our odour control solutions for rendering plants combine chemical scrubbers, biofilters, biotrickling filters, and hybrid systems designed to treat complex odourous compounds such as hydrogen sulfide (H₂S), ammonia, amines, and volatile organic compounds (VOCs). Each system is engineered for high efficiency, achieving up to 95–99% odour removal while minimising energy use and maintenance costs.

Key strengths of our rendering-specific systems include:

  1. End-to-End Design and Installation: From air capture ducts and exhaust systems to treatment units and stack dispersion.
  2. Hybrid Odour Control Systems: Combining biological and chemical filtration to manage varying odour loads efficiently.
  3. Onsite Odour Monitoring: Continuous H₂S and ammonia measurement for real-time performance tracking and compliance.
  4. Integrated Wastewater and Sludge Odour Control: Managing emissions from process water, condensate, and sludge handling.

By integrating these systems, Elixir Enviro Systems helps rendering facilities move beyond compliance — transforming odour control into a strategic sustainability advantage. Our goal is to engineer odour-free, community-friendly, and ESG-aligned rendering operations that reflect true environmental responsibility.

Conclusion

Odour control in rendering plants is no longer just about removing smells — it’s about engineering a cleaner, more responsible future for industries that serve the circular economy. With advanced air treatment systems, integrated wastewater solutions, and data-driven monitoring, companies can now operate efficiently, meet stringent regulations, and maintain community trust.

Elixir Enviro Systems continues to pioneer this transformation — designing and delivering odour control systems that redefine sustainability in rendering operations. By combining innovation with environmental ethics, the industry can truly render change — for the planet and its people.

Looking to Upgrade Odour Control in Your Rendering Facility?

Connect with Elixir Enviro Systems — specialists in designing end-to-end odour management solutions tailored to your process. From advanced scrubbers, biofilters, and hybrid systems to real-time monitoring and wastewater treatment, we ensure performance, compliance, and peace of mind.

Explore more about our Industrial Odour Control and Wastewater Treatment Solutions at www.elixirenviro.in.

FAQs on Odour Control in Rendering Plants

1. What is a rendering plant?

A rendering plant is a facility that processes animal by-products — such as offal, fat, bones, and carcasses — collected from slaughterhouses, butcher shops, supermarkets, and farms. The goal is to convert waste materials into valuable, reusable products like tallow, grease, and bone meal, which are later used in the manufacture of soaps, animal feed (including pet food), fertilizers, and various industrial goods.

2. What are different types of rendering?

Rendering plants are classified into edible and inedible types. Edible rendering plants process clean, food-grade by-products from slaughterhouses and meat processing facilities to produce edible fats like tallow and lard used in food and cosmetics. Inedible rendering plants, on the other hand, handle materials unfit for human consumption—such as carcasses, condemned meat, and offal—to produce non-edible tallow, grease, and meat and bone meal used in animal feed, biodiesel, and industrial applications.

Based on the processing method, rendering can also be categorized as wet rendering and dry rendering. Wet rendering uses steam or hot water to separate fat from solids, yielding higher-quality fat but consuming more energy and water. Dry rendering involves heating materials without water and separating fat mechanically—an energy-efficient process suited for inedible rendering but with stronger odour emissions. Plants may also operate in batch or continuous modes, depending on scale and production demand. Together, these variations define how rendering plants operate to balance efficiency, product quality, and environmental control.

3. What causes odour in rendering plants?

Rendering plants generate odour from the decomposition of animal by-products such as fat, blood, and offal. During processes like cooking, drying, and storage, gases containing hydrogen sulfide (H₂S), amines, and volatile organic compounds (VOCs) are released. Without proper control, these emissions can cause strong, unpleasant odours and environmental complaints.

4. What are the most effective odour control technologies for rendering plants?

The most effective odour control systems combine biological and chemical treatment methods. Technologies like biofilters, biotrickling filters, and chemical scrubbers remove odourous gases efficiently. In many facilities, hybrid systems — combining biological and non-biological units — achieve up to 99% odour removal efficiency, ensuring regulatory compliance and community satisfaction.

5. How do biofilters help in odour control?

Biofilters use naturally occurring microorganisms to degrade odorous compounds into harmless by-products such as water and carbon dioxide. They are highly effective against amines, mercaptans, and reduced sulfur compounds, offering 85–95% odour removal efficiency. Biofilters are also sustainable, low-maintenance, and ideal for continuous operation in rendering facilities.

6. What are hybrid odour control systems?

Hybrid odour control systems integrate multiple technologies—such as chemical scrubbers with biofilters, or biotrickling filters with chemical scrubbers, Thermal systems & Biological units—to handle diverse odour compounds. This multi-stage treatment ensures maximum odour removal efficiency and consistent air quality, even in high-load rendering operations.

7. How does Elixir Enviro Systems help rendering plants manage odour?

Elixir Enviro Systems provides custom-engineered odour control solutions specifically for rendering plants. Their systems include biofilters, chemical scrubbers, biotrickling filters, and hybrid combinations that effectively remove H₂S, ammonia, VOCs, and amines. Elixir also offers onsite monitoring, wastewater odour treatment, and pilot studies to ensure optimal performance and long-term sustainability.

8. Why is odour control important for sustainability and ESG compliance?

Effective odour control demonstrates a rendering plant’s commitment to environmental, social, and governance (ESG) principles. By reducing air emissions, improving workplace and community health, and ensuring transparent environmental performance, rendering facilities strengthen their sustainability credentials and public trust.

9. How can rendering facilities upgrade their existing odour control systems?

Facilities can upgrade by integrating advanced hybrid systems, adding real-time monitoring units, or improving air capture and ventilation designs. Elixir Enviro Systems offers system audits, performance analysis, and retrofit solutions to enhance odour removal efficiency and reduce operational costs.

Odour and Emission Control in Technical Rubber Manufacturing Units: A Path Toward Sustainable Operations

Introduction

Ever walked into a rubber manufacturing plant and been hit by that strong, unmistakable smell? If so, you’re not alone. The odour from technical rubber manufacturing isn’t just a nuisance, it’s a complex mix of chemicals, process emissions, and, if left unmanaged, a regulatory and community relations challenge. But here’s the good news: odour control in rubber plants is 100% solvable!

Natural Rubber or processed latex is used in different industrial applications. But generally, it is not directly used. Raw natural rubber has several limitations that make it unsuitable for direct industrial use, especially in applications like tires, gaskets, conveyor belts, and industrial rubber products. Therefore, it undergoes further processing to make it technically fit for most of the industrial applications, making it Natural Technical Rubber (NTR). Technical rubber is important as it ensures consistent performance, improved processability, meets global standard and is sustainable alternative to synthetic rubber.

The key properties of Natural Technical Rubber are the following

  1. High Elasticity & Resilience – Excellent for shock absorption
  2. Tear & Abrasion Resistance – Ideal for tires, belts, and seals
  3. Heat & Aging Resistance – Improved through processing
  4. Low Impurities – Consistent quality for industrial processing

Different countries have specific grading systems for NTR, commonly known as Technically Specified Rubber (TSR); in India it is known by the name ISNR (Indian Standard Natural Rubber), in Thailand its STR (Standard Thai Rubber), in Malaysia its SMR (Standard Malaysian Rubber) etc. TSR 20 is the most used grade worldwide, primarily in tires, industrial rubber products, and conveyor belts.

Technical rubber manufacturing supports key industries such as automotive, aerospace, construction, and healthcare. However, one persistent challenge is the emission of strong odours caused by the release of volatile organic compounds (VOCs), sulfur compounds, and other airborne contaminants during processes like vulcanization, compounding, and extrusion.

Odour emission control is essential for regulatory compliance, worker health, and maintaining harmonious community relations. Below, we explore the root causes of odours, the associated challenges, and solutions for effective odour management.

What Causes Odour in Rubber Manufacturing?

  1. Vulcanization Process: The cross-linking of rubber molecules using sulfur or peroxides releases hydrogen sulfide (H₂S), mercaptans, and other sulfur-containing compounds, which have a strong, unpleasant odour.
  2. Rubber Compounding: The addition of processing oils, resins, and chemical accelerators can lead to the release of VOCs such as benzene, toluene, and styrene, contributing to odour emissions.
  3. Mixing and Extrusion: The heating of rubber compounds during mixing and extrusion generates fumes containing hydrocarbons, ammonia, and organic acids.
  4. Solvent-Based Adhesives: The use of solvents in rubber processing and finishing results in emissions of volatile organic compounds, which can cause odour issues.
  5. Wastewater Treatment: The presence of organic contaminants and residual chemicals in wastewater can generate odorous gases such as ammonia, hydrogen sulfide, and methane.

Challenges in Odour Control

  1. Complex Chemical Composition: Odours from rubber manufacturing are caused by a mix of chemicals with varying volatility, making them difficult to capture and neutralize.
  2. High Temperature Processes: Many rubber processing steps occur at elevated temperatures, which increases the volatilization of odour-causing compounds.
  3. Regulatory Compliance: Strict environmental regulations require manufacturers to adopt effective odour control measures, necessitating investment in advanced technologies.
  4. Workplace Safety: Exposure to odorous emissions can cause headaches, nausea, and respiratory irritation, impacting worker health and productivity.
  5. Community Complaints: Persistent odour issues can lead to complaints from nearby residential areas, potentially resulting in legal and operational challenges.

Effective Odour Control Solutions

1. Process Optimization

  1. Implementing closed-system processing and efficient material handling techniques can help reduce odour emissions at the source.
  2. Using low-odour or alternative raw materials in rubber formulation can minimize the release of volatile compounds

2. Activated Carbon Filtration

  1. Activated carbon filters are highly effective in adsorbing VOCs and sulfur compounds from process air.
  2. These filters can be installed in ventilation systems to capture odorous gases before they are released into the atmosphere.

3. Biofiltration Systems

  1. Biofilters use microorganisms to break down odorous compounds into non-volatile byproducts.
  2. This eco-friendly approach is particularly effective for treating hydrogen sulfide and organic odours from exhaust air streams.

4. Chemical Scrubbing

  1. Wet scrubbers use chemical reagents to neutralize acidic and basic odorous compounds.
  2. Commonly used scrubbing agents include sodium hydroxide for acidic gases and sodium hypochlorite for organic odours.

5. Thermal Oxidation

  1. Thermal oxidizers combust VOCs and odour-causing compounds at high temperatures, converting them into harmless CO₂ and H₂O.
  2. Regenerative thermal oxidizers (RTOs) improve energy efficiency and are suitable for large-scale rubber manufacturing facilities.

Emission Control = Operational Excellence

For technical rubber manufacturers, effective odour and emission control is no longer just a compliance checkbox — it is part of being a future-ready manufacturer. From regulatory resilience to supply chain credibility to employee satisfaction, clean air initiatives deliver far-reaching operational and business benefits. The best companies aren’t just reacting to complaints; they’re proactively investing in sustainable solutions.

Elixir Enviro Systems’ Role in Odour Control

At Elixir Enviro Systems, we provide customized odour control solutions for technical rubber manufacturing units. Our expertise includes:

  1. Biofiltration Systems: We design and install biofilters that use natural microorganisms to break down odorous compounds efficiently, ensuring compliance with environmental regulations.
  2. Chemical Scrubbing: Our advanced wet scrubbers neutralize harmful sulfur compounds and VOCs, reducing odour emissions effectively.
  3. Activated Carbon Adsorption: We offer activated carbon filtration solutions to capture airborne contaminants and improve air quality in rubber manufacturing plants.
  4. Odour Monitoring & Assessment: Our onsite odour measurement and assessment services help identify odour sources and recommend targeted control strategies.
  5. Pilot Studies & Custom Solutions: We conduct pilot studies to evaluate the best odour control technologies for specific industrial processes, ensuring optimal results.

By implementing our innovative and sustainable odour control solutions, rubber manufacturers can achieve regulatory compliance, enhance workplace safety, and improve community relations.

Conclusion

Odour control in technical rubber manufacturing isn’t just about meeting regulations — it’s about creating a safer workplace, protecting the environment, and strengthening your brand’s commitment to sustainable practices. By combining process optimization with advanced treatment technologies, manufacturers can significantly reduce odour emissions and enhance operational performance.

At Elixir Enviro Systems, we specialize in comprehensive, customized odour control solutions for rubber manufacturing and other industrial sectors. From biofilters to chemical scrubbers to advanced monitoring solutions, we help you stay compliant, sustainable, and community-friendly.