Comparison of odor treatment system: advantages and disadvantages
Introduction
Currently, countries are acting more rigorously with the care of the environment based on different established measures. A clear example is the regulation of the generation of odors that are emitted into the environment from industrial processes.
Governments or environmental entities are not the only ones that require compliance with laws to control industrial odors. Today society plays a very important role as public opinion when it comes to planet Earth, its care and its pollution.
There are various technologies with their advantages and disadvantages, and with different functions for odor control, such as:
Biofilter Technology
The process air, which contains the annoying odor, is treated using a filter material and eliminated by microorganisms located therein, and can reduce various compounds such as sulfides, ammonias and amines. Then, the clean air is released into the atmosphere, leaving the residual drainage (nitrates and sulfides) as a contaminant that must necessarily be treated, because, otherwise, they continue to cause bad odors.
This system can treat flows of 200 to 10,000 m3/h, requires water for its operation and a large area for its implementation, using little electrical energy.
To avoid damaging the filter material, periodic maintenance should be considered. When it comes to process air with a high dust content, it is mandatory and necessary to treat it, for example, using a gas scrubber.
It is considered a good technology due to its cost/efficiency ratio, obtaining results that reach 85% of odors eliminated. Regarding investment costs, although they may vary by brand, manufacturer or model, they generally range between USD 700,000 and USD 1,000,000.
Ozone and UV light treatment technology
The air flow, which must be less than 60,000 mm3/h, first passes through the UV lights where the ammonias, sulfides and amines are decomposed, and then decompose the remaining compounds with catalysts by injecting ozone (O3).
It is important to remove dust from the air of the process as it will damage the effectiveness of the UV light. That is, highly contaminated air can considerably affect the efficiency of the system due to the flow density.
On the other hand, it uses electrical energy for its operation and the air must not exceed 60°C nor the humidity must be greater than 85%.
This treatment allows you to achieve good results, reaching levels of 80 to 90%. Regarding investment costs, they are considered between USD 200,000 and USD 400,000, with high annual operating costs.
Non-thermal plasma technology
Technology capable of treating flows ranging from 5,000 m3/h to 200,000 m3/h. These devices use ambient air to generate free or active oxygen (O1), which has a high oxidation power with the molecules that contain the annoying odor. In order to obtain the active oxygens, the air must pass through a stage of filters to rid them of impurities and then goes through the cabinet with non-thermal plasma modules, where the dissociation of the molecules is achieved and the aforementioned oxygens are obtained. . These are injected into the outlet duct where the annoying odors come from and in just 1 second the odor molecules react and oxidize, becoming imperceptible to our nose.
Unlike other technologies, non-thermal plasma does not use water or chemicals for its operation so it does not generate a secondary contaminated by-product, it only requires a minimum of electrical energy. In addition to the large flow rates that it can treat, there is no restriction on the humidity or temperature that the process air can have.
Optimal results are achieved, reaching levels of up to 95% of odors eliminated.
They are systems that easily adapt to existing installations, thanks to their flexibility and little space they take up. Regarding investment levels, these range from EUR 120,000 to EUR 250,000.
Scrubber technology
The air coming from the process, which contains the annoying odor, comes into contact with the stream of water and drip-type chemicals and, in this way, the odors adhere to the liquid and the air is released into the atmosphere cleanly. .
Scrubbers, also known as gas scrubbers, can treat air flows that contain dust, without the need to use filters. They can treat flows ranging from 1,000 to 180,000 m3/h, achieving good results from 50% to 90% of controlled odors.
A great disadvantage they have is that strict control of the contaminated water generated after the process is required, and it also occupies a large area for its installation.
The investment can reach up to USD 250,000 with high operating costs close to USD 150,000 per year.
Conclusion
The choice and installation of the appropriate system will depend, on the one hand, on the industrial process that needs to be treated, considering the components of the contaminated air and, on the other hand, on the levels of odor control that must be achieved to comply with regulations current in each country.
As a summary, see a comparative table of the technologies presented with their advantages and disadvantages, considering the following as a score: 5 highly positive, 4 positive, 3 medium, 2 negative and 1 highly negative.
