How Does the Biological Deodorization Method Treat VOC Exhaust Gases?

A biological deodorization tower mainly uses microbial decomposition to eliminate odors. In principle, any kind of waste gas can be treated using a biological deodorization tower. Among these gases, some are classified as VOCs (volatile organic compounds). So, how exactly does a biological deodorization tower treat VOC exhaust gases?

The biological method involves using microorganisms to absorb and decompose organic gases containing compounds such as benzene, toluene, and xylene ("BTX"). This is an emerging technology that leverages the ability of microbial strains to absorb organic gases as nutrients during their growth and reproduction processes. These harmful components are degraded into carbon dioxide, water, and microbial biomass, thus achieving waste gas purification.

This method has a broad applicable concentration range, requires low investment, is easy to operate and maintain, causes no secondary pollution, and improves over time as microorganisms adapt to the waste gas, resulting in more stable and effective treatment. A key to the success of this method is the selection and cultivation of suitable microbial strains.

The core of the biological method for treating VOCs lies in biofilm technology. The basic principle involves microbial breeding techniques where specialized microbial strains are cultivated, acclimated, and enriched to form a diverse microbial community. These strains are then inoculated onto the surface of porous packing materials to form a biofilm. When VOC-laden gas passes through the packed tower, pollutants diffuse and transfer to the biofilm surface. Under suitable environmental conditions, biochemical reactions catalyzed by microbial enzymes occur, breaking down VOCs into carbon dioxide, water, and cell biomass—thus purifying the exhaust gas.

The application of biological treatment technology to VOC purification has only emerged in recent years. Common biological treatment processes include biofiltration, biotrickling filtration, bioscrubbing, membrane bioreactors, and rotating biological contactor filters.

Biofilm-based treatment uses microbial metabolism to biologically degrade various organic and some inorganic pollutants, converting them into CO₂ and H₂O, thereby effectively removing contaminants from industrial exhaust gases. This method features simple equipment, low operation and maintenance costs, and no secondary pollution. However, it has limitations when treating complex or hard-to-degrade VOCs, as the removal efficiency may vary. It also requires large equipment volume and long retention times, and the effectiveness varies with different types of packing materials.

The above content summarizes the principles and methods of using biological deodorization to treat VOCs. When treating such gases, these guidelines can serve as a reference to help ensure effective odor removal.