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Biofiltration for Odor and VOC Removal. INTRODUCTION. H 2 O. BIOMASS SUPPORT MEDIA. Clean gas outlet. H 2 O. Waste gas Inlet. Humidifying Chamber. Pump. Blower. Pump. Biofilter. Drain. Conceptual Design of a Typical Biofiltration System. PROCESS ENGINEERING FUNDAMENTALS.
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H2O BIOMASS SUPPORT MEDIA Clean gas outlet H2O Waste gas Inlet Humidifying Chamber Pump Blower Pump Biofilter Drain Conceptual Design of a Typical Biofiltration System
FILTER MEDIA BIOFILM GAS PHASE Reaction Controlled Zone Reaction Controlled Borderline Situation Diffusion Controlled Zone Diffusion Controlled Reaction Free Zone Simplified Biophysical Model of Biofiltration
Biodegradability of Various Contaminants in Biofilters (Continued)
Important Considerations in Deciding Waste Airflow in Biofilters
ATTACHED GROWTH versus ARTIFICIAL IMMOBILIZATION
Differences between Attached Growth Systems and Entrapment Immobilization Technology
Differences between Attached Growth and Entrapment Immobilization (Cont’d)
Main principles of immobilization processes • 1. Treatment of gases by attached growth systems - Self attachment of microorganisms to the filter bedding material • 2. Treatment of gases by systems that contain microorganisms entrapped within polymer beads -artificial immobilization of the microorganisms to or within the filter bedding material • microencapsulation - wrapping droplets containing microorganisms with a thin membrane; microorganisms can freely move within capsule, consuming substrates that penetrate through membrane • membrane separation - microorganisms are separated from the bulk fluid by the use of sheets of membrane, which allow substrates to penetrate. Usually porous UF membranes (0.002-0.1 m). Selective membranes also used, e.g. those separating CO2 and H2S from CH4
Main principles of immobilization processes(cont’d) • microorganisms entrapment within 3D polymer matrix - pores in matrix smaller than microbial cells, keeping them trapped within the material, but the pores allow penetration of substrates • covalent bonding and covalent crosslinking - creation of covalent bonds between reactive groups on the surfaces of cells and different ligands on the bedding material. Coupling agents used to activate ligands (most common is glutaraldyde; isocynate and amino silane also frequently used).
Comparison between natural polymers and synthetic polymers used for microbial entrapment (for wastewater treatment)