Further Information for Lecture 8
Additional Pages I have prepared for you contain information about the uses, applications, advantages & disadvantages of each process - just click to be taken directly to the page:
Air sparging
Enhanced air sparging
Bio-venting
Enhanced bio-venting
Bio-slurping
Natural Attenuation
Bio-filtration (click or see below)
Air sparging
Enhanced air sparging
Bio-venting
Enhanced bio-venting
Bio-slurping
Natural Attenuation
Bio-filtration (click or see below)
Play this animation to visually see how a bio-filter decontaminates both liquid and gaseous states...
Bio-Filtration
Typical Methanotrophic Biofilm Reactor
Effective air pollution control!
Process:
Uses:
Advantages:
Process:
- 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:
- Effectively treats non-halogenated VOCs and fuel hydrocarbons.
- Can also treat Halogenated VOCs - just less effective (these are less bio-degadable).
- Often used to control odours from compost piles.
Advantages:
- Low-cost (~$5 - $10/kg of contaminant).
- Highly effective air pollution control (APC) technology
- Biofilters degrade the contaminants to harmless products.
- More time & cost effective than activated carbon adsorbers (GAC) because:.
- Bio-regeneration (instead of physical replacement) of the film maintains the maximum adsorption capacity available, thus contaminants are desorbed at a quicker rate
- The contaminants are destroyed not just separated (the case in G.A.C. technologies).
- Reduced time and capital & operating costs.
- Air flow rate in 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 accumulate, (ie too high concentration of contaminant for the rate of MO growth) - would then require periodic mechanical cleaning.
- Only effective for certain biodegradable contaminants (as for all biological processes).
External Links provide even further information and case studies for each application:
- Air-Sparging & Bio-venting: http://www.etecllc.com/air-sparge.asp Information and Case Studies
- AIR SPARGING
- BIOREMEDIATION - IN SITU GROUNDWATER
- BIOREMEDIATION - IN SITU LAGOON
- BIOVENTING
- A Citizen’s Guide to Soil Vapour Extraction and Air Sparging: (EPA 542-F-01-006) Download (80K / PDF)
- A Citizen’s Guide to Monitored Natural Attenuation: (EPA 542-F-01-004) Download (91K / PDF)