In today's environmentally conscious world, effective odour management has become a critical priority for municipalities, industries, and environmental operations. Unpleasant odours from sewage treatment plants, landfills, remediation sites, and industrial facilities pose significant challenges—not only creating nuisance issues for nearby communities but also indicating underlying operational inefficiencies and potential health concerns. This comprehensive guide explores the science, technologies, and best practices for odour control across these diverse applications.
Understanding the Science of Odour Formation
Before addressing odour control strategies, it is essential to understand the fundamental processes that generate malodours in various settings. The primary culprits behind most environmental and industrial odours are volatile organic compounds (VOCs) and inorganic gases produced through biological and chemical processes.
The Role of Hydrogen Sulphide in Sewage Systems
In wastewater and sewage environments, hydrogen sulphide (H₂S) stands out as the most problematic odour-causing compound. This gas, characterised by its distinctive "rotten egg" smell, forms when sulfate-reducing bacteria thrive in anaerobic conditions within sewer pipes and treatment facilities. When sewage flows slowly or remains stagnant, oxygen levels decrease, creating ideal conditions for these bacteria to convert sulphate compounds into hydrogen sulphide.
The implications of H₂S extend beyond mere nuisance. At concentrations as low as 0.1-0.5 mg/L dissolved sulphide, concrete corrosion begins to occur in sewer infrastructure. More severe corrosion happens at levels above 2 mg/L, with corrosion rates ranging from 1.1 to 10 mm per year. This deterioration results in enormous economic costs—estimated at $14 billion annually in the United States alone, with Australia facing approximately $100 million per year in infrastructure losses.
Landfill Gas Generation and Odour Compounds
Landfills present unique odour challenges due to the complex decomposition processes occurring within waste masses. As organic materials break down, they generate a cocktail of odorous compounds including ammonia, methane, volatile organic compounds, mercaptans, and various sulfur species. The composition and intensity of these odours vary depending on waste type, moisture content, temperature, and the stage of decomposition.
The problem is compounded by the diffuse nature of landfill emissions—unlike point sources such as exhaust stacks, landfill odours emanate from large surface areas, making containment and treatment more challenging. Weather conditions, particularly wind patterns and atmospheric pressure, significantly influence odour dispersion, with low-pressure systems encouraging gas migration to the surface rather than into collection systems.
Industrial and Remediation Site Odours
Industrial facilities and environmental remediation sites generate odours specific to their processes and contaminants. Food processing plants produce odours from proteins, fats, and carbohydrates decomposing. Manufacturing operations may release chemical VOCs, while remediation projects disturb contaminated soils, releasing trapped volatile compounds including petroleum hydrocarbons, trimethylamine, and various industrial chemicals.
Sewage and Wastewater Odour Control Technologies
Effective sewage odour management requires a multi-layered approach that addresses both the source of odour generation and the treatment of odorous gases before they reach the surrounding environment.
Liquid Phase Control Methods
The most effective sewage odour control begins in the liquid phase, preventing H₂S formation before it can transfer to the air. Several strategies have proven successful in Australian and international wastewater networks.
Chemical Dosing Systems represent the frontline defence against hydrogen sulphide. Oxidising agents such as hydrogen peroxide, ozone, and chlorine dioxide target sulfides at their source, converting them into less harmful compounds. Magnesium hydroxide and lime dosing raise the pH of wastewater above 7, which keeps hydrogen sulphide in its dissolved, non-volatile form (HS⁻ and S²⁻), significantly reducing gas-phase emissions.
Recent Australian research has revolutionised chemical dosing through next-generation control algorithms. Advanced projects involving major universities and water utilities have developed network-wide dosing control systems that use real-time monitoring and predictive modeling. These intelligent systems achieve 40-50% reductions in chemical consumption while maintaining superior odour control compared to traditional methods. The systems employ autoregressive models based on current flow measurements to predict sulfide production, determining optimal ferrous salt or magnesium hydroxide dosing in real-time.
Iron Salt Addition using ferrous chloride or ferrous sulfate provides a cost-effective approach to binding dissolved sulfides. Research has shown that combining ferrous chloride dosing with pH adjustment creates synergistic effects, reducing both liquid-phase sulfide levels and gas-phase H₂S concentrations. This combined method proves more efficient and cost-effective while producing less sludge than traditional approaches.
Vapour Phase Treatment Systems
Once odorous gases form in sewer systems, vapour phase treatment provides the second line of defence. Modern wastewater facilities employ several sophisticated technologies to treat contaminated air before release.
Biofilters have emerged as one of the most sustainable and cost-effective vapour treatment technologies. These systems use layered beds of organic material—typically wood chips, bark, or specialised media—colonised by microorganisms that convert odorous compounds into harmless byproducts. The bacteria within biofilters metabolise hydrogen sulphide, ammonia, and VOCs, converting them to carbon dioxide, water, and biomass through natural biodegradation processes.
Properly designed biofilters achieve removal efficiencies exceeding 90% for most odorous compounds, with some advanced systems reaching 99.5% effectiveness. Modern implementations demonstrate this approach, combining biofilters with activated carbon polishing to eliminate 99.9% of odours from sewer gases. These systems extract hydrogen sulphide and other gases using large fans, treating them through biological and adsorption processes before releasing clean, odourless air through tall vent stacks.
The key to biofilter success lies in maintaining optimal conditions for microbial activity. Air entering the biofilter must be between 25°C and 45°C with humidity above 90%—preferably saturated. The biofilter bed consists of two primary layers: a lower coarse hardwood layer (50-150 mm particles) providing structural support and air distribution, and an upper layer of finer material (25-45 mm) where most biological activity occurs. A fine bark "topper" layer insulates the system and retains moisture.
Activated Carbon Filtration provides exceptional performance for high-concentration applications or as polishing stages following biological treatment. Activated carbon's vast internal surface area—typically 500-1,500 m²/g—provides countless adsorption sites where odour molecules become trapped. Standard activated carbon performs well for general applications, but specialised impregnated carbons enhance performance for specific compounds.
Caustic-impregnated activated carbon excels at removing hydrogen sulphide and mercaptans, particularly valuable in sewer applications where these compounds dominate. Water-regenerable catalytic activated carbon represents an innovative advancement, converting adsorbed H₂S to sulfuric acid through catalytic oxidation, then regenerating capacity through simple water washing. This technology significantly extends operational life while reducing replacement costs. Field implementations report odour removal efficiencies consistently above 99.5% with 40% reductions in annual operating costs compared to chemical scrubbing.
Hybrid and Integrated Approaches
The most advanced wastewater facilities now employ hybrid systems combining multiple technologies for comprehensive odour management. Multi-stage treatments pairing bio-scrubbers for bulk H₂S removal with activated carbon polishing achieve consistent 99.9% removal rates. These integrated approaches optimise both efficiency and cost-effectiveness, with biological systems handling high volumes at lower operating costs while carbon provides reliability for final treatment.
Modern design guidelines emphasise a holistic odour management framework integrating source control, preventative design measures, and curative interventions throughout the wastewater system lifecycle. This comprehensive approach addresses turbulence minimisation, detention time reduction, ventilation optimization, and strategic chemical dosing placement to maintain dissolved sulfide below 0.5 mg/L and average H₂S concentrations below 5 ppm in gas spaces.
Landfill Odour Management Strategies
Landfills present distinct challenges requiring specialised approaches that account for large diffuse emission sources, variable waste composition, weather-dependent dispersion patterns, and complex gas generation processes.
Source Control and Surface Treatment
The foundation of landfill odour management involves controlling emissions at their source through operational best practices and surface treatments.
Operational Best Practices significantly reduce odour generation through careful waste management procedures. Keeping tipping areas as small as possible minimises exposed waste surfaces that generate odours. Covering waste promptly—ideally daily with soil, alternative daily cover materials, or temporary barriers—traps odorous gases before they can disperse. Installing permanent capping over completed operational areas provides long-term odour containment while facilitating gas collection.
Advanced landfill operations demonstrate source control through comprehensive infrastructure improvements. Modern facilities install extensive temporary rainfall barriers that serve dual purposes: preventing rainwater from waterlogging the landfill surface and blocking landfill gas escape during low atmospheric pressure periods. These barriers, combined with sealed and capped surfaces, effectively divert water away from odour-generating zones. Where water cannot be diverted, naturally occurring zeolite keeps surfaces dry, preventing the muddy, odorous conditions that develop when heavy machinery operates on saturated landfills.
Specialised Surface Sprays create protective barriers over odorous materials using various technologies. Advanced formulations use natural clay-based compounds that dry to form protective coatings, physically sealing odorous surfaces. Bio-based neutralisers work at the molecular level, chemically altering odour compounds rather than merely masking them. Enzyme-based treatments accelerate organic matter decomposition, reducing anaerobic odour generation.
Atmospheric Management and Suppression Systems
For diffuse landfill emissions, atmospheric treatment systems distribute odour control agents across large areas.
Misting and Fogging Systems provide flexible, scalable solutions for landfill odour suppression. These systems atomise water-based neutraliser solutions into fine droplets that remain suspended in air, maximising contact with odorous molecules. High-pressure atomising nozzles create droplets of 10-50 microns that effectively capture dust particles and odour molecules without wetting surfaces or materials.
Large-area misting systems deploy fixed nozzle arrays around landfill perimeters and active areas, creating invisible barriers that intercept odours before they travel off-site. Mobile fog cannons provide targeted treatment for hotspot areas, with throw distances ranging from 15 to 150 metres depending on cannon size. These systems can be automated to activate based on meteorological triggers—wind direction, wind speed, and atmospheric pressure—ensuring treatment occurs during highest-risk periods.
Field applications report up to 95% odour reduction when misting systems employ proper neutraliser chemistry and strategic placement. The technology proves particularly valuable for temporary operations or situations requiring rapid deployment without extensive infrastructure.
Landfill Gas Collection and Utilization
Effective gas collection infrastructure provides the most permanent solution to landfill odour issues while generating energy.
Modern landfills employ extensive networks of vertical wells and horizontal collection pipelines that extract methane and odorous gases from the waste mass. While methane itself is odourless, the collection system simultaneously captures hydrogen sulphide, VOCs, and other odour-causing compounds as byproducts. These gases feed power generation facilities where combustion at high temperatures destroys odorous compounds while generating electricity.
Advanced infrastructure includes horizontal gas extraction pipelines specifically designed to improve collection from areas previously prone to odour emissions. This essential infrastructure supports greater gas extraction capacity, preventing odorous gases from migrating to the surface and travelling off-site. Natural odour neutralisers derived from pine, aniseed, clove, lime and other plant sources provide temporary odour suppression during infrastructure installation when small amounts of waste are briefly exposed.
Advanced Monitoring and Prediction
Proactive odour management increasingly relies on sophisticated monitoring and predictive technologies that enable facilities to prevent complaints rather than merely respond to them.
Real-time odour monitoring networks deploy sensors throughout landfill sites and surrounding communities, providing continuous data on odour intensity and composition. Meteorological modeling integrates weather forecasts with site operations, predicting odour dispersion patterns up to 72 hours in advance. This allows operators to schedule high-risk activities during favourable weather conditions and activate suppression systems preemptively.
AI-powered systems correlate weather patterns with historical odour events, learning site-specific relationships between atmospheric conditions and odour risks. Modern facilities implement advanced monitoring platforms enabling hourly reporting of odour impacts and providing data-driven decision support. This proactive approach has proven highly beneficial in preventing complaints and responding with factual information when concerns arise.
Environmental Remediation Site Odour Control
Environmental remediation projects face unique odour challenges due to temporary operations, variable contaminant types, and the disturbance of materials that have trapped volatile compounds for years.
Soil Excavation and Treatment Odours
Excavating contaminated soils releases trapped volatile organic compounds accumulated over decades, creating intense but localised odour events. Ex-situ treatment processes—including thermal desorption, chemical oxidation, and bioremediation—generate additional emissions as contaminants are processed.
Specialised Foam Applications provide immediate source control by sealing contaminated surfaces upon excavation. These foams create temporary barriers preventing volatilisation while excavated materials are transported or processed. Bio-remediation enhancement agents accelerate natural decomposition of organic contaminants, reducing both treatment time and odour generation duration. Chemical stabilisation binds odorous compounds, preventing their release during handling and treatment.
Enclosure Systems for excavation and treatment areas contain odours at the source, allowing for controlled treatment of concentrated emissions. Temporary structures with negative air pressure ensure odorous air flows into treatment systems rather than dispersing to surrounding areas. The captured air can be treated through portable biofilters, mobile activated carbon units, or thermal oxidation systems depending on contaminant characteristics and concentrations.
Mobile and Rapid Deployment Solutions
The temporary nature of remediation projects requires flexible systems that can be quickly deployed, relocated, and demobilised without extensive infrastructure investment.
Portable Fog Cannon Systems provide active suppression for remediation sites. These mobile units can be repositioned as work progresses, targeting odours at excavation faces, staging areas, and transport routes. Rapid deployment misting barriers around work zones create invisible curtains that intercept odours before they travel beyond site boundaries.
Mobile Activated Carbon Units treat high-concentration odour events with efficiency exceeding 99%, making them ideal for remediation applications where odorous compounds may be released in sudden bursts. These skid-mounted or trailer-mounted systems require only electrical power and can operate immediately upon startup, responding instantaneously to changes in odour concentration.
Temporary Biofilter Systems for enclosed treatment areas provide sustainable odour control for longer-duration remediation projects. While requiring more setup time than carbon systems, biofilters offer lower operating costs for extended operations, particularly effective when contaminant types are compatible with biological degradation.
Contaminant-Specific Treatment Approaches
Different remediation scenarios require tailored odour control strategies matched to specific contaminants.
For petroleum-hydrocarbon contaminated sites, citrus terpene-based neutralisers and activated carbon prove particularly effective. Sites with fish-processing residues or trimethylamine contamination require specialised formulations targeting nitrogen-containing organic compounds. Industrial chemical sites may need multi-stage treatments addressing both organic and inorganic odorous species.
Recent remediation projects have demonstrated continuous suppression systems maintaining non-detectable odour levels at site boundaries throughout excavation and treatment operations. Success requires thorough pre-project characterisation of expected contaminants, design of appropriate treatment systems, and real-time monitoring to adjust operations as conditions change.
Industrial Odour Control Solutions
Industrial facilities spanning manufacturing, food processing, agriculture, and chemical production require customised odour control approaches matched to their specific operational characteristics and emission profiles.
Manufacturing and Chemical Processing
Manufacturing operations generate diverse odorous emissions requiring targeted treatment technologies.
Advanced Scrubber Systems provide high-efficiency treatment for chemical processing facilities. Chemical scrubbers circulate liquid solutions that absorb and neutralise odorous gases through chemical reactions. Caustic scrubbers effectively remove acidic gases including hydrogen sulphide and organic acids, while acidic scrubbers target alkaline compounds like ammonia. Multi-stage scrubber systems address complex odour profiles containing both acidic and alkaline species.
Thermal Oxidation destroys organic odorous compounds through high-temperature combustion, typically between 650°C and 1,200°C. This approach achieves destruction efficiencies exceeding 99% for most organic compounds, making it suitable for high-strength industrial odours from paint manufacturing, resin production, and chemical synthesis operations. While energy-intensive, thermal oxidation provides complete odour elimination rather than transfer to another medium.
Biotrickling Filters combine biological and chemical processes, offering compact footprints and effectiveness for high H₂S and VOC concentrations. Odorous air passes through packed beds where microorganisms degrade odour-causing compounds while nutrient-rich liquid continuously trickles over the bed maintaining optimal microbial activity. These systems require less space than conventional biofilters while handling higher loading rates.
Food and Beverage Processing
Food processing facilities face unique challenges from protein, fat, and carbohydrate decomposition producing intense but variable odours.
Enzyme-Based Treatments target specific organic compounds prevalent in food processing. Four-enzyme formulations digest proteins, fats, carbohydrates, and cellulose, addressing the full spectrum of food-related odours. These products work through odour-pairing at the molecular level, chemically altering malodorous molecules rather than masking them.
Applications include direct treatment of wastewater streams, fogging in processing areas, and addition to wash-down solutions. Enzyme products eliminate odours from decaying organic matter, animal waste, fish processing residues, and rotting vegetation with effectiveness exceeding 92-97% when properly applied.
Specialised Biofilter Systems designed specifically for food processing odours employ media selections and microbial communities optimised for proteins, fats, and sugars. These systems handle the variable loading typical of batch food processing operations while maintaining high removal efficiencies.
Agricultural and Livestock Operations
Animal agriculture generates significant odour challenges from manure storage, composting, and waste treatment operations.
Molecular Neutralisation Technology forms the basis of modern agricultural odour control, breaking down odorous compounds at the molecular level into harmless byproducts like water and CO₂. Advanced formulations achieve permanent odour elimination rather than temporary masking, with applications including wastewater treatment, livestock facilities, and composting operations.
Products like Anotec 0307 and PRO5L can be applied via fogging, spraying, misting, or direct dosing into liquid waste streams. These formulations are fully water-miscible, non-toxic, and biodegradable, ensuring safety for animals, workers, and the environment.
Composting Enhancement Systems reduce odour generation by optimising aerobic decomposition conditions. Proper aeration prevents anaerobic "hot spots" that generate intense odours, while nutritional management programs alter livestock diets to reduce odour precursors in manure. Biocover systems for manure storage facilities provide physical barriers reducing emissions while supporting microbial populations that consume odorous compounds.
Technology Integration and Automation
Modern industrial odour control increasingly incorporates smart technologies for optimisation and reliability.
IoT Sensors provide continuous monitoring of odour levels, H₂S concentrations, airflow rates, temperature, and humidity. This real-time data feeds AI-driven optimisation algorithms that automatically adjust treatment parameters—chemical dosing rates, biofilter moisture, scrubber pH, and fan speeds—maintaining optimal performance under varying conditions.
Predictive Maintenance Systems analyse performance trends to forecast equipment failures before they occur, scheduling interventions during planned downtime rather than emergency shutdowns. Cloud-based analytics enable performance comparison across multiple facilities, identifying best practices and optimisation opportunities.
Research into advanced control systems demonstrates these principles, with algorithms reducing chemical consumption by 40-50% while maintaining superior odour control through intelligent, data-driven dosing decisions.
Emerging Technologies and Best Practices
The odour control industry continues evolving with innovations promising greater effectiveness, sustainability, and cost-efficiency.
Next-Generation Biological Systems
Advances in biofilter technology are extending operational life and improving performance.
Engineered Inorganic Media with design lives exceeding 20 years overcome the degradation limitations of traditional organic media. These synthetic materials maintain structural integrity and porosity indefinitely while supporting robust microbial populations. Biotrickling Filters for high-concentration applications combine the benefits of biological treatment with chemical absorption, handling loading rates impossible for conventional biofilters.
Hybrid Systems Combining Absorption and Biological Oxidation optimise treatment for complex odour profiles, with absorption providing immediate response to concentration spikes while biological processes provide sustained degradation of captured compounds.
Advanced Oxidation Processes
Ozone Treatment effectively oxidises a wide range of odorous compounds including VOCs and hydrogen sulphide without leaving harmful residues. While energy-intensive, ozone systems provide rapid treatment suitable for high-concentration intermittent releases.
Nanotechnology Applications enhance molecular interactions between treatment agents and odour compounds, improving neutralisation efficiency while reducing chemical consumption. Research into nano-structured catalysts for H₂S oxidation promises significant performance improvements in activated carbon and catalytic systems.
Sustainable and Green Technologies
Environmental consciousness drives development of treatment methods minimising chemical usage, energy consumption, and waste generation.
Renewable Energy Integration reduces operational carbon footprints by powering treatment systems with solar, wind, or biogas-derived electricity. Several Australian facilities now operate carbon-neutral odour control systems through renewable energy integration and carbon offset programs.
Circular Economy Approaches repurpose waste streams from odour control as valuable resources. Sulfur recovered from H₂S treatment finds applications in agriculture and chemical manufacturing. Spent biofilter media becomes high-quality compost. Water-regenerable activated carbon dramatically reduces solid waste compared to disposable carbon systems.
Plant-Based Neutraliser Formulations derived from essential oils, terpenes, and plant extracts provide effective molecular neutralisation without synthetic chemicals. These biodegradable formulations prove safe for humans, animals, and aquatic life while achieving odour removal efficiencies comparable to traditional chemical treatments.
Smart Monitoring and Predictive Management
Artificial Intelligence and Machine Learning revolutionise odour control through predictive modeling and automated response.
Systems learn site-specific relationships between meteorological conditions, operational parameters, and odour events, forecasting problems up to 72 hours in advance. Automated response protocols activate treatment systems, adjust processing schedules, or implement contingency measures before odours reach community impact thresholds.
Community Engagement Platforms integrated with odour management systems foster transparency and collaborative relationships with surrounding residents. Web portals allow communities to report odour observations, view real-time monitoring data, and track facility responses, building trust through open communication. This approach moves stakeholder relationships from disengagement toward collaborative engagement where communities become partners in effective odour management.
Best Practices for Comprehensive Odour Management
Successful odour control across sewage, landfill, remediation, and industrial applications requires strategic implementation of proven methodologies.
Assessment and Planning
Thorough Source Characterisation identifies specific odorous compounds, emission rates, and generation mechanisms. This may involve odour panel assessments, instrumental analysis of air samples, and process reviews to understand generation pathways. Proper characterisation ensures treatment system selection matches actual odour characteristics rather than assumptions.
Site-Specific Design tailors solutions to unique facility requirements, considering operational schedules, space constraints, budget parameters, regulatory requirements, and community sensitivity. Generic approaches rarely achieve optimal results—effective systems reflect individual facility needs.
Hierarchy of Controls
The most effective odour management follows a logical hierarchy prioritising prevention over treatment.
Source Control addresses odours at their point of generation through process modifications, operational improvements, and preventative measures. Examples include minimising detention times in wastewater systems, maintaining aerobic conditions in composting, covering waste promptly at landfills, and optimising process parameters in manufacturing.
Containment and Capture employs enclosures, covers, and ventilation systems to prevent odour dispersion, directing emissions to treatment systems rather than atmospheric release.
Treatment Technologies selected based on odour characteristics, concentration, volume, and regulatory requirements form the final defence. Multi-stage approaches often provide optimal performance, with different technologies addressing different aspects of complex odour profiles.
Operational Excellence
Continuous Monitoring through sensors, laboratory analysis, and odour panel assessments provides data for performance evaluation and optimisation. Modern facilities employ real-time H₂S monitors, flow meters, temperature sensors, and pressure indicators feeding centralised control systems.
Preventive Maintenance schedules ensure treatment systems operate at design efficiency. Biofilters require moisture monitoring and periodic media replacement. Activated carbon systems need regular breakthrough monitoring and timely media changes. Chemical dosing equipment requires calibration and inspection.
Staff Training ensures operators understand odour generation mechanisms, treatment principles, monitoring requirements, and emergency response protocols. Well-trained staff identify emerging issues before they escalate into community complaints.
Regulatory Compliance and Community Relations
Successful facilities maintain compliance with environmental regulations while fostering positive community relationships.
Proactive Communication with regulators and neighbours builds trust and goodwill. Regular updates on operations, monitoring results, and improvement projects demonstrate commitment to environmental stewardship. Transparent complaint response processes with timely investigation and corrective action show respect for community concerns.
Continuous Improvement programs systematically evaluate performance, identify enhancement opportunities, and implement innovations. Leading facilities benchmark against industry best practices, participate in research collaborations, and invest in emerging technologies to maintain operational excellence.
Conclusion: The Future of Odour Control
Effective odour control across sewage treatment, landfills, remediation, and industrial applications requires comprehensive understanding of odour generation mechanisms, appropriate technology selection, and commitment to operational excellence. As environmental regulations continue tightening and community awareness increases, organisations must adopt proactive odour management strategies that exceed compliance requirements to achieve true operational sustainability.
The future of odour control lies in integrated solutions combining multiple technologies, real-time monitoring, and predictive management capabilities. Advances in biological systems, catalytic materials, nanotechnology, artificial intelligence, and renewable energy integration promise superior odour control while minimising environmental impact. Australian leadership in areas such as intelligent chemical dosing control, advanced biofilter design, and predictive meteorological modeling demonstrates the nation's commitment to environmental innovation.
For facilities seeking to transform their odour management strategies, success requires partnering with experienced providers who understand the science, technologies, and operational realities of odour control. Anotec Environmental specialises in molecular neutralisation technology that breaks down odorous compounds into harmless byproducts, offering customised solutions for wastewater treatment, landfills, remediation, and industrial applications. From initial assessment through system design, implementation, and ongoing support, comprehensive odour control services ensure facilities achieve their objectives effectively and efficiently while maintaining positive relationships with regulators and communities.
By embracing advanced odour control technologies and best practices, Australian facilities can protect public health, preserve environmental quality, maintain regulatory compliance, and foster harmonious community relationships—transforming odour challenges into opportunities for operational excellence and environmental leadership.
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