Bio-filters
Advantages
Low environmental impact since it’s a natural biological process.
Low investment and maintenance costs: the natural process requires a lower energy consumption compared to other technologies.
High efficiency: air purification over 90% makes them a valid alternative to other filtration systems.
Applications
Biological purification of polluted air
Bio-filtration is one of filtering technologies for air purification systems which specifically need to remove polluting and odorous emissions such as Volatile Organic Compounds. Bio-filtration is a bioremediation technology for gaseous emissions. Polluting and malodorous organic compounds are oxidized and metabolized by aerobic and mesophilic microorganisms (bacteria, molds, fungi and yeast). Biological oxidation has significant advantages in the treatment of medium-low concentrations of Volatile Organic Compounds (VOC): in these cases, the bio-filter allows high abatement efficiency with a wide range of products with reduced contact times. Bio-filtration is convenient both from total management costs and environmental points of view, achieving the degradation of the pollutant. In many cases, bio-filtration is even more efficient compared to other chemical/physical solutions since the various biological agents are able to reproduce on pollutants getting a cross and complete action.
The air to be treated is carried through the filtering bed which is a solid mold made of products deriving from the mechanical processing of vegetal waste. Thus, polluting substances spread within the watery biofilm which adheres to the wood-cellulosic mold, becoming available to the group of naturally present microorganisms. They draw energy by oxidizing or metabolizing the compounds, consequently making them odorless. This biocoenosis of microorganisms, that is the basic element for the technology functioning, needs appropriate conditions to be able to proliferate and perform their function. Therefore, in order to obtain an efficient air treatment, it’s necessary to maintain certain values of incoming airflow rates, pH, temperature, porosity and humidity of the filtering bed, relative humidity of the incoming airflow. Finally, airflow rates to be treated mustn’t contain concentrations and substances which are incompatible with the vitality of the microorganisms.