Off-gas/Waste Vapour/Hazardous Volatile Treatment
Bio-Filtration
Typical Methanotrophic Biofilm Reactor Diagram
Process:
Uses:
Advantages:
Limitations:
- Effective air pollution control, where the vapour-phase organic contaminants are passed through a bed of porous media.
- The contaminants sorb to the media surface - are degraded by microorganisms in the media.
- Specific strains of bacteria may be introduced into the filter and optimal conditions provided to preferentially degrade specific compounds.
Uses:
- Primarily Treatment groups: non-halogenated VOCs and fuel hydrocarbons.
- Can also treat Halogenated VOCs - just less effective process.
- Have been successfully used to control odours from compost piles.
Advantages:
- Low-cost
- Highly effective air pollution control (APC) technology
- Biofilters change nearly all the contaminants to harmless products - under apt conditions.
- Advantages over activated carbon adsorbers (GAC) because:.
- Bio-regeneration maintains the maximum adsorption capacity available, therefore the mass transfer zone remains stationary and relatively short.
- The filter does not require regeneration
- The required bed length is significantly less.
- The contaminants are destroyed not just separated - just separated with activated carbon (GAC) technologies.
- These advantages reduce capital & operating costs.
Limitations:
- The rate of influent air flow is constrained by the size of the biofilter.
- Fugitive fungi may be a problem.
- Low temperatures may slow/stop removal unless the biofilter is climate-controlled.
- Filter flooding/plugging may occur if excessive biomass accumulation - periodic mechanical cleaning of filter required.
- Effectiveness is highly dependent upon the biodegradability of the contaminants - same for all biological processes