Frequently asked Questions (FAQ’s)

FAQ Category

Odour is a complex sensory phenomenon involving interaction of many compounds. The human nose is a very sensitive detector for certain compounds. Odour is evaluated in terms of odour units. Odour emission from industrial and commercial establishment invariably attracts adverse public attention. It is also an issue affecting labour relations.

Odour emitted from industries contains complexes chemical compositions. It can be combinations of many Volatile Organic Carbons (VOCs), ammonia (NH3), Sulphur Dioxide (SO2), Hydrogen sulphide(H2S), Mercaptons, amines etc. Many wishes to see what is inside, meaning what chemical constitute the odour. Therefore, in many cases, one or more different specific chemical sensors are used to measure the odour electronically.

Odor pollution refers to the presence of unpleasant or offensive odors in the environment that can negatively impact human health, well-being, and quality of life. It occurs when odorous substances are released into the air from various sources such as industrial processes, waste management facilities, agriculture, and sewage treatment plants. Odor pollution can cause annoyance, discomfort, and respiratory issues in individuals exposed to it. Effective odor control measures are implemented to mitigate and minimize the impact of odor pollution on the surrounding community.

Odour control is the process of managing and reducing unpleasant or offensive odours in various environments, such as wastewater treatment plants, industrial facilities, landfills, or commercial spaces.

It involves implementing measures and technologies to minimize the generation, minimising dispersion by implementing the mitigation activities, and improving air quality and reducing nuisance for surrounding communities. Among these the first and foremost thing is to have a good mitigation plan or the odour control system; second ways to avoid/minimise the fugitive emissions from the facility.

Effective odour control is important for several reasons. It helps to maintain a pleasant and healthy living and working environment for the employees and communities near odour-emitting sources. It also addresses regulatory compliance requirements and mitigates potential negative impacts on public health, quality of life, and property values. Another important aspect is applicable for Odour control measures can also help maintain good relationships between industries and communities. For industries, maintaining a good relationship with the communities around their facility is a key parameter; there are many examples wherein the factories were shut just because the protest from the neighbourhood. Also, for industries involved in the export of products, the products is often receives premium prices upon having different types of environmental protection in place including the odour control systems especially for red category industries.

Common sources of odours include industrial processes (such as chemical manufacturing, food processing including slaughterhouses, feed manufacturing, rendering plants, rubber processing, paper industries, plywood manufacturing, foundries and petrochemical industries), wastewater treatment plants, composting facilities, livestock farms, and commercial facilities (such as restaurants, paint shops and waste storage areas). These sources can emit various odorous compounds, including sulphur compounds, volatile organic compounds (VOCs), ammonia, and other organic or inorganic substances.

A wide range of odour abatement technologies is available including Biofilters, Bioscrubbers, Chemical Scrubbers, Activated carbon Filters and catalytic/thermal oxidation systems etc. The choice of the to be used depends on many factors including required odour removal efficiencies, flow rate & inlet odour concentration, type of chemical species in the odour, variability in flow and load, space requirements and infrastructure (power, drainage, etc). Biofilter is considered to be an eco-friendly and cost-effective technology to eliminate the volatile organic compounds (VOCs), H2S, Ammonia and other odorous gases from the exhaust gas stream. In most cases, when you look at the least possible Life-time cost, the Biofilter turns out to be the lowest cost or the cheapest of all the alternatives available (One of our clients had replaced imported cold plasma technology with biofilter, due to the very low life time cost)

Odours can be measured and monitored using various techniques. Field inspectors and trained panelists may conduct odorant intensity assessments based on human perception. Instrumental methods, such as olfactometry, use specialized equipment to measure and quantify odour concentrations. Additionally, ambient air sampling and analysis can be performed to identify specific odorous compounds present. Continuous monitoring systems may also be installed to provide real-time data on odour levels.

Odour can be measured both electronically and by using olfactometers. The electronic odour measurement units are otherwise called as e-noses in many places. Whereas the olfactometer uses human to asses the odour.

In case of e-noses or electronic noses, the odour is measured using an array of chemical sensors and each chemical sensor shall be giving the concentration of a particular chemical. The disadvantage is that the measurement/values shall be available only for those sensors which are installed in the particular model. But, the odour in general is a result of very complex combination of many different chemicals and therefore in many countries, odour measurement is usually done by a technique known as dynamic olfactometry. A panel of trained persons smell the gas sample at various dilutions. They find out at what dilution the odour is barely perceptible. Dynamic olfactometry uses a diluted flow of sample presented to odour panel. The panel then asses the odour and expresses the value as Odour unit or dilution threshold. Many cases, Field olfactometers are used to measure odour in field, especially to avoid expensive collection of large volume air samples

Different jurisdictions may have regulations and standards in place to regulate and manage odours. These regulations often set limits on odour concentrations, establish emission control requirements, and outline the obligations of odour-emitting facilities. Standards such as VDI 3880 and EN 13725 provide guidelines for odour measurement and assessment. Compliance with these regulations and standards helps ensure effective odour control and mitigate the impact on surrounding communities.

Odour control should be considered during the design phase of facilities to minimize potential odour issues. This includes proper selection and placement of equipment, installation of ventilation systems, consideration of potential emission points, and implementation of appropriate odour control technologies. Engaging environmental engineers and odour control specialists early in the design process allows for the incorporation of effective control measures and can help reduce future challenges.

Engaging and involving communities in odour control efforts is crucial. This can be done through community outreach programs, public consultations, and proactive communication. Providing information about odour control measures, addressing concerns, and implementing transparent monitoring systems can help build trust and foster a cooperative relationship between industries and communities. Regular communication channels, such as dedicated hotlines or online platforms, can also enable community members to report odour incidents or provide feedback.

Best practices for odour control include regular maintenance and inspection of equipment, implementing appropriate containment measures, optimizing process conditions, and utilizing effective odour control technologies. Monitoring odour emissions, conducting periodic assessments, and addressing any issues promptly are also important. Implementing a comprehensive odour management plan, considering community feedback, and staying informed about technological advancements in odour control are additional best practices to ensure effective and sustainable odour control.

Biofilter in general is biological system that work in the principle of attached growth. People call biofilter for both wastewater treatment system and for Odour control in case of Air Pollution Control. Both the systems are entirely different units both in terms of application/usage and the way it looks. The term “Biofilter” in wastewater treatment is mainly used in aquaculture/fish farms. It can be either a Moving Bed Bio-Reactor (MBBR) or Trickling Filter configuration.

Biofilter for Odour control on the other hand is used in many industries such as Fish processing industries, rendering plants, feed manufacturing industries, bone processing industries, foundries, painting shops, plywood manufacturing industries, pharmaceutical industries, speciality chemical manufacturers, rubber processing industries, paper manufacturing industries, food-spice processing units, fiber glass units etc for their process and ventilation air treatment, Municipal Solid waste treatment plant and wastewater treatment plants (Sewage treatment plants-STPs and Effluent Treatment plants-ETPs) for the odour control.

Biofilter is best suited for odour control of Medium to low strength odour control. This doesn’t mean that the biofilter is not suitable for high strength odour control. For high strength odour control, the biofilter can be used with suitable pre-treatment technologies; mainly to the fact that the air treated using biofilter is far superior to any other alternatives.

The pre requisites for installation of a biofilter is as listed below.

  1. For any kind of odour treatment system including biofilters there should be no leakage of air from the source to external environment so the source/ processing area should be completely closed and the whole air needs to be fed to the treatment system.
  2. There should be sufficient space for installing the biofilters and provision for duct routing should be also available.
  3. There should be provision for providing the required electrical power for the machines associated with the system, the rating of the same depends on the capacity of the plant and processing methods used.
  4. Fresh water should be available at site for providing moisture to the biofilters and for any kind of pre conditioning if required.

All kinds of biofilter systems generally include a Blower for suction of odorous air from the source, a ducting system for routing the air, a humidification system or its equivalent for pre conditioning the air the biofilter for removal of odorous compounds from the air stream. The general block diagram is as shown below.

These kinds of biofilters are generally used for medium and higher odour concentration applications. The area required for installation will be more and the time required for installation will be also more.

The main components of any odour treatment system includes the following.

  1. Suction Hoods – These are used for capturing the air from the source efficiently such that mixing up of the odorous air with ambient air is minimized.
  2. Air Duct – The purpose of the air duct is to route the air suctioned from the hood and direct it to the odour treatment section.
  3. Blower – The air blower provides the necessary pressure to suction the odorous air from the source to the biofilter in the designed manner.
  4. Humidification System – This is a preconditioning stage for the odorous air to achieve the required moisture level to be fed to the biofilter. In some cases, some other pre-treatment systems are installed instead of humidifier which will be capable of providing the same humidifying action as mentioned above.
  5. Biofilter – This is the main stage which deals with the removal of odorous compounds from the suctioned air stream and releases odour free air into the atmosphere.

The advantages of biofilters is as follows.

  • It is the most efficient method for odour removal from flue gas.
  • Installation and operation cost is low as compared to other kind of systems.
  • Generally, is the lowest lifetime cost among all types of Odour Control Units (OCUs)
  • Does not contain any use of chemicals for the process as this is a purely biological system.
  • The operation has higher level of simplicity and less maintenance.
  • Doesn’t require any consumables such as bacteria addition or other nutrients once the system is in operation.

The disadvantages of biofilters include.

  • For higher odour concentrations it may require larger area for installation the system.
  • The bacteria/micro-organisms involved in the degradation of odourous compounds takes up the required nutrients either from the air or from the biological media. Therefore, the media gets consumed as the time progresses. So, the whole media needs to be changed when the life is completed, and this can happen within a time range of 3 to 5 years

The power required for operation is dependent on the size/kind of the treatment plant as the design for each plant is customized for its application there is no general power consumption data available to establish this. To a minimum power requirement can be for the blower which is used to deliver the air to the Biofilter, about 30minutes per day the biofilter must be irrigated-so one pump and the power required for the pre-treatment units, if any. Generally, the installation in each location is depends on the process they follow, and the end result they wanted.

The pre-treatments depend upon the process parameters of the factory or establishment where the odour control to be installed. This can range from

  1. Humidifiers
  2. Dust Removal System / Dust Scrubbers
  3. Water Scrubbers
  4. Condensers / Heat exchangers
  5. Dehumidifying towers, etc to name a few.

Size of the biofilter is dependent on the odour concentration, production capacity (the estimated Odour load), total flow rate and the type of industry for which the treatment plant needs to be made.

The details required for sizing of a biofilter includes.

  • The site/factory and machine layout
  • Production process and production capacity
  • Odour sources in the process
  • Details of any flue gas outlet blowers if available
  • Detailed description of the processing steps
  • In secondary stage site visit and odour measurement may be required.

We offer different types of Biofiters now – Standard rate Biofilters and High rate Biofilters. Other than this, we have different configurations of the Biofilter systems, including single storey system, multiple-floor system, container-based design etc.

Standard rate biofilters uses modified media from CSIR-NIIST (government of India), a patented media which is being made market suitable based on our experience, which we market under the brand name Cocofil. The second and the recent invention of EES is the High-Rate Biofilters, suitable for places where the area available for the installation is very small. The high rate biofilters require only 1/6th or less footprint compared to the Standard rate Biofilters, which is a proprietary design of EES, this is branded and sold as Ultrafil Biofilters.

Biofilters, also known as biofiltration systems, are typically designed with a cover or roofing structure to protect the filter media and provide environmental control. The roofing helps maintain consistent operating conditions within the biofilter and prevents the filter media from getting wet or exposed to extreme weather conditions. It also helps regulate the temperature and humidity inside the biofilter, which is important for the growth and activity of the microbial communities responsible for odour or pollutant removal. Additionally, the roofing helps prevent rainwater from entering the biofilter, which could potentially cause clogging or reduce the filter’s effectiveness.

The lowest lifecycle cost system for odour control can vary depending on specific factors such as the scale of the operation, type and concentration of odorous compounds, regulatory requirements, and available resources. However, some commonly used and cost-effective odour control systems include biofiltration, activated carbon adsorption, and chemical scrubbing. Each of these systems has its own advantages and considerations in terms of capital costs, operating costs, maintenance requirements, and effectiveness in odour removal. A thorough evaluation of the specific needs and conditions of the facility is necessary to determine the most cost-effective system for odour control.

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