Controlling Odor in Industrial Processes

  • 14 avril 2020
  • Author: Tim Daniels
  • Number of views: 4375

As the world’s population has increased, urban centers have expanded and created sprawl. Cities and their suburbs have engulfed rural and industrial areas like never before. As a result, longtime residents of these areas, such as industrial plants and facilities, have been forced to adapt. Issues that were never a concern previously, are now taking precedent. Among these concerns are the odors that are emitted as a byproduct of processes. These odors must be controlled, reduced, or eliminated altogether. Plant stake-holders must understand a number of different aspects of their operations in order to prevent or address the odors that are being emitted. Renderers are among the most affected by this and thus will be the focus of this article. Some of the factors that renderers must consider are:

  1. Type/Age of the Material
  2. Byproducts being created
  3. Scrubbing process

It’s important to understand both the mechanical process that is producing the odors and the molecular makeup of the odor compounds that need to be controlled. Start by identifying the materials being used and the way in which these materials are being converted to the final product. Generally, odors that are released are a byproduct of this process.

Type/Age of the Material
Renderers process animal byproducts such as animal fat, bone, feathers, hides, blood, and internal organs. Generally, a 1,000 pound steer has about 600 pounds of edible meat. The remaining 400 pounds is processed by renderers. (Franco, 1996) The perishable nature of the material being processed results in odors being emitted from plants. The longer a material is stored without being processed, the more odor compounds are created and emitted. These odors are a very intricate mixture of organic compounds. 

Byproducts Being Created
There are thirty or more odor causing byproducts being created in a rendering plant. Among the major compounds are organic sulfides, disulfides, aldehydes, amines, organic acids, alcohols, ketones, and hydrocarbons. (Burgwald TA., 1971)  Some of these compounds, such as Hydrogen Sulfide (H₂S), have very low odor thresholds. These compounds can be detected at levels as low as 1 ppb. As a result, highly efficient odor control processes are necessary.

Odor Removal Processes
The two most commonly used processes to remove odor compounds from the air are: boiler incineration and multistage wet scrubber systems.  

  • Incineration
    Incineration in boilers is a commonly used practice across the country. This is because rendering plants require steam for cooking and drying material and therefor have boilers. Odorous air is introduced to the boiler as either the primary or secondary combustion air, although precautions must be made to remove moisture and particulate matter. This is usually done with a scrubber and entrainment separator.
  • Multistage Wet Scrubbers
    Wet scrubbers, sometimes called packed-bed scrubbers are an alternative when incineration is not an option. A typical wet scrubber system consists of two or three stages; a venturi scrubber, which removes particulate matter, followed in sequence by a packed-bed scrubber(s). This scrubber contains plastic packing that vary in shape and size and are designed to maximize contact between the air and scrubber solution. The odorous air flows upward in the scrubber as recirculating water (scrubber solution) with an oxidizing solution, such as Chlorine Dioxide or odoreXile™, flows downward.

As demands for space and food continue to rise, manufactures will continue to be pressed more and more. Renderers will be processing ever increasing amounts of material while being told to reduce their odor emissions. Chem-Aqua has an expansive product line ready to address any odor control need or situation. We are also able to create and install generator systems customized to fit any application. Our field representatives have experience with Chlorine Dioxide, Paracetic Acid, odoreXile, and more. Contact Chem-Aqua today to have an experienced representative survey your facility and lend their expertise.

Written by: Tim Daniels


Burgwald TA. (1971). Identification of Chemical Constituents in Rendering Industry Odor Emissions, project no C8172. Chicago: IIT Research Institute.

Franco, D. A. (1996). The Original Recyclers. In D. A. Franco, The Original Recyclers (p. 33). The National Renderers Association.

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