Biofiltration Technology
Overview
Biofiltration Systems Overview
Biofiltration is a low-cost and highly effective air pollution control (APC) technology that can
significantly decrease capital and long-term operating costs compared to conventional competitive
technologies such as carbon filtration or oxidation. Proven commercially in Europe since the early
1990’s, biofiltration has been used successfully to control a number of air contaminants such as
noxious odors, Volatile Organic Compounds (VOCs), and Hazardous Air Pollutants (HAPs)
stemming from a wide range of industrial and public sector sources. Consistent control efficiencies
of greater than 90% have been achieved by TRG Biofilter for many common air pollutants and up
to 99.9% for H2S emitted from POTWs.
In biofiltration, the polluted effluent air is passed through an all-natural, biologically active filter, or
biofilter. Naturally occurring microorganisms in the biofilter convert the air pollutants into harmless
by-products that are primarily carbon dioxide (CO2) and water (H2O).
Biofiltration is based on a process that occurs naturally in soils and water and thus represents a
safe, environmentally friendly "green" technology. The biofilter itself is non-hazardous and remains
so. There are no hazardous by-products that need to be addressed. In competing, conventional
technologies like carbon, absorption recycling and disposal typically are ongoing, increasing the
costs of operation. This fact makes biofiltration a more cost-effective solution for air pollution
control applications.
Process Description
Microorganisms live in a bed of biofilter packing material consisting of a mixture of rocks, compost,
activated sludge, or other hard support material that avoids long-term compaction problems. The
bed is housed in an open or an enclosed vessel ranging in size from small 1,000 gallon tanks to
large buildings. A blower is used to move the air through the biofilter, and an air dispersion system
ensures evenly distributed flow in the bed. High moisture is constantly maintained in the biofilter
bed. The ideal operating temperature is 15ºC to 43ºC (59ºF to 110ºF).
The microorganisms exist in a biofilm, or biologically active water film, located on the bed
materials. Biofilters require moisture, nutrients, and enough energy to move air across the biofilter
bed. Usually the head loss across a biofilter bed is only one to two inches of water. As the
contaminated air passes through the bed, the contaminants make contact with the
microorganisms in the biofilm and are consumed, much as people consume food for energy. As a
result of this metabolism, harmless carbon dioxide (CO2) and water (H2O) are released, and the
microorganisms in the biofilm thrive and are regenerated.
Economics
The startup costs for biofiltration are comparable to those for more conventional air pollution
control technologies such as carbon adsorption and incineration, yet ongoing operating and
maintenance costs are substantially lower. As a result, with the correct air pollution control
applications, biofiltration becomes the clear economical choice over the life cycle of the air
pollution control system. For example, with biofiltration, there are no long-term costs associated
with recycling air pollutants, as there are in carbon filtration. There are no external fuel costs such
as those associated with thermal oxidation technologies, where such costs are ongoing and
increase with the cost of inflation. Controlling the costs of such unknowns must be considered
when selecting competing technologies. Therefore, from a pure economic comparison, biofiltration
is clearly superior, especially for high flow rates streams with low concentrations of pollutants.
Biofiltration becomes more economical than carbon adsorption or oxidation when airflow rates are
high and VOC pollutant concentrations are under 3000 PPM, which is a typical toxicity limit for the
biomass. Most biofilters operate at VOC concentrations of 1000 PPM and below.
Biofiltration is also superior from an environmental or "green" point of view. It consumes very little
energy. Its all-natural and organic technology does not accumulate any residual toxic wastes, as
does carbon adsorption, nor emit any NOx as oxidizers or incinerators do.
Odorous air pollutants emitted at a fish processing plant
in Baja California, Mexico.
Applications
Biofiltration is ideally suited for the treatment of volatile organic and odorous compounds in air
resulting from a wide range of manufacturing operations or from organic decomposition, including
H2S. The simplest compounds to treat are hydrocarbon molecules, ranging from alcohols and
ketones to the heavy molecules found in JP-4 and JP-5 jet fuels. Fluorocarbons can also be
treated, depending on type.
Animal Feed Houses
Baking
Chemical Processing
Composting
Fiberboard Production
Fish Procesing
Food Production
Meatpacking
Metalworking
Municipal Waste
Paints & Coatings
Petroleum Refining
Pharmaceuticals
Pulp & Paper Mills
Printing
Rubber Productions
Soil Vapor Extraction
Wastewater Treatment
Biofiltration Technology
While biofiltration looks simple on the surface, it is in fact a complex bio-mechanical system, which
requires specialized knowledge and technology for efficient, long-term performance. Applying
years of experience and state-of-the-art technical advancements, TRG Biofilter’s 7th generation
products are unmatched worldwide for efficient and trouble-free long-term performance.
TRG's modern line of biofilters resolve a number of challenges that thwart other biofilters. They
overcome challenging conditions including the presence of acidic media that can terminate the
activity of the microorganisms, channelization that can allow air streams to pass through the
biofilter bed untreated, and compaction that can block the passage of the air streams across the
biomass. In conjunction with its academic partners, TRG Biofilter has developed mathematical
modeling tools to optimize the design of biofilters to meet specified throughput and efficiency
objectives, plus remote monitoring tools to facilitate maintenance and optimize performance. TRG
Biofilter’s measuring devices for determining the performance of the biofilter are the most
advanced in the world.
TRG Biofilter’s early applications include treating gasoline vapors from a soil extraction site,
treating ethanol, MEK and MIBK from manufacturing sites, and treating JP-4 jet fuel vapors at a
United States Air Force base. Most recently, TRG Biofilter won recognition and funding from the
California Air Resource Board (CARB) for its large-scale and highly efficient air biofiltration system
at the Ojai Valley Sanitary District (CA), a wastewater treatment facility (also referred to as a
publicly owned treatment works or POTW). TRG Biofilter approached this challenge and provided
a solution that won CARB approval.
The Ojai project involved unique challenges and required a two-stage biofilter. The first stage
holds an inert, readily drained, acid-resistant support medium that is capable of operating at low
pH to allow the microorganisms to remove hydrogen sulfide gas (H 2S). Removal of the H2S is
crucial, as it tends to form sulfuric acid (H2SO4) that can terminate the life of the microorganisms.
The second stage uses a biofilter media that is appropriate for a normal pH and provides the
environment for microorganisms to remove the remaining voltatile organic compounds (VOCs).
TRG Biofilter
Turnkey Biofiltration Systems
Tel: (714) 730-5397
Fax: (714) 730-6476
250 El Camino Real #204
Tustin, CA 92780, USA
E-mail: sales@trgbiofilter.com
Contact TRG Biofilter
m
To TRG Biofilter Home Page
Biofiltration Technology
Overview
Biofiltration Systems Overview
Biofiltration is a low-cost and highly effective air pollution control (APC) technology that can
significantly decrease capital and long-term operating costs compared to conventional competitive
technologies such as carbon filtration or oxidation. Proven commercially in Europe since the early
1990’s, biofiltration has been used successfully to control a number of air contaminants such as
noxious odors, Volatile Organic Compounds (VOCs), and Hazardous Air Pollutants (HAPs)
stemming from a wide range of industrial and public sector sources. Consistent control efficiencies
of greater than 90% have been achieved by TRG Biofilter for many common air pollutants and up
to 99.9% for H2S emitted from POTWs.
In biofiltration, the polluted effluent air is passed through an all-natural, biologically active filter, or
biofilter. Naturally occurring microorganisms in the biofilter convert the air pollutants into harmless
by-products that are primarily carbon dioxide (CO2) and water (H2O).
Biofiltration is based on a process that occurs naturally in soils and water and thus represents a
safe, environmentally friendly "green" technology. The biofilter itself is non-hazardous and remains
so. There are no hazardous by-products that need to be addressed. In competing, conventional
technologies like carbon, absorption recycling and disposal typically are ongoing, increasing the
costs of operation. This fact makes biofiltration a more cost-effective solution for air pollution
control applications.
Process Description
Microorganisms live in a bed of biofilter packing material consisting of a mixture of rocks, compost,
activated sludge, or other hard support material that avoids long-term compaction problems. The
bed is housed in an open or an enclosed vessel ranging in size from small 1,000 gallon tanks to
large buildings. A blower is used to move the air through the biofilter, and an air dispersion system
ensures evenly distributed flow in the bed. High moisture is constantly maintained in the biofilter
bed. The ideal operating temperature is 15ºC to 43ºC (59ºF to 110ºF).
The microorganisms exist in a biofilm, or biologically active water film, located on the bed
materials. Biofilters require moisture, nutrients, and enough energy to move air across the biofilter
bed. Usually the head loss across a biofilter bed is only one to two inches of water. As the
contaminated air passes through the bed, the contaminants make contact with the
microorganisms in the biofilm and are consumed, much as people consume food for energy. As a
result of this metabolism, harmless carbon dioxide (CO2) and water (H2O) are released, and the
microorganisms in the biofilm thrive and are regenerated.
Economics
The startup costs for biofiltration are comparable to those for more conventional air pollution
control technologies such as carbon adsorption and incineration, yet ongoing operating and
maintenance costs are substantially lower. As a result, with the correct air pollution control
applications, biofiltration becomes the clear economical choice over the life cycle of the air
pollution control system. For example, with biofiltration, there are no long-term costs associated
with recycling air pollutants, as there are in carbon filtration. There are no external fuel costs such
as those associated with thermal oxidation technologies, where such costs are ongoing and
increase with the cost of inflation. Controlling the costs of such unknowns must be considered
when selecting competing technologies. Therefore, from a pure economic comparison, biofiltration
is clearly superior, especially for high flow rates streams with low concentrations of pollutants.
Biofiltration becomes more economical than carbon adsorption or oxidation when airflow rates are
high and VOC pollutant concentrations are under 3000 PPM, which is a typical toxicity limit for the
biomass. Most biofilters operate at VOC concentrations of 1000 PPM and below.
Biofiltration is also superior from an environmental or "green" point of view. It consumes very little
energy. Its all-natural and organic technology does not accumulate any residual toxic wastes, as
does carbon adsorption, nor emit any NOx as oxidizers or incinerators do.
Odorous air pollutants emitted at a fish processing plant
in Baja California, Mexico.
Applications
Biofiltration is ideally suited for the treatment of volatile organic and odorous compounds in air
resulting from a wide range of manufacturing operations or from organic decomposition, including
H2S. The simplest compounds to treat are hydrocarbon molecules, ranging from alcohols and
ketones to the heavy molecules found in JP-4 and JP-5 jet fuels. Fluorocarbons can also be
treated, depending on type.
Animal Feed Houses
Baking
Chemical Processing
Composting
Fiberboard Production
Fish Procesing
Food Production
Meatpacking
Metalworking
Municipal Waste
Paints & Coatings
Petroleum Refining
Pharmaceuticals
Pulp & Paper Mills
Printing
Rubber Productions
Soil Vapor Extraction
Wastewater Treatment
Biofiltration Technology
While biofiltration looks simple on the surface, it is in fact a complex bio-mechanical system, which
requires specialized knowledge and technology for efficient, long-term performance. Applying
years of experience and state-of-the-art technical advancements, TRG Biofilter’s 7th generation
products are unmatched worldwide for efficient and trouble-free long-term performance.
TRG's modern line of biofilters resolve a number of challenges that thwart other biofilters. They
overcome challenging conditions including the presence of acidic media that can terminate the
activity of the microorganisms, channelization that can allow air streams to pass through the
biofilter bed untreated, and compaction that can block the passage of the air streams across the
biomass. In conjunction with its academic partners, TRG Biofilter has developed mathematical
modeling tools to optimize the design of biofilters to meet specified throughput and efficiency
objectives, plus remote monitoring tools to facilitate maintenance and optimize performance. TRG
Biofilter’s measuring devices for determining the performance of the biofilter are the most
advanced in the world.
TRG Biofilter’s early applications include treating gasoline vapors from a soil extraction site,
treating ethanol, MEK and MIBK from manufacturing sites, and treating JP-4 jet fuel vapors at a
United States Air Force base. Most recently, TRG Biofilter won recognition and funding from the
California Air Resource Board (CARB) for its large-scale and highly efficient air biofiltration system
at the Ojai Valley Sanitary District (CA), a wastewater treatment facility (also referred to as a
publicly owned treatment works or POTW). TRG Biofilter approached this challenge and provided
a solution that won CARB approval.
The Ojai project involved unique challenges and required a two-stage biofilter. The first stage
holds an inert, readily drained, acid-resistant support medium that is capable of operating at low
pH to allow the microorganisms to remove hydrogen sulfide gas (H2S). Removal of the H2S is
crucial, as it tends to form sulfuric acid (H2SO4) that can terminate the life of the microorganisms.
The second stage uses a biofilter media that is appropriate for a normal pH and provides the
environment for microorganisms to remove the remaining voltatile organic compounds (VOCs).
TRG Biofilter
Turnkey Biofiltration Systems
Tel: (714) 730-5397
Fax: (714) 730-6476
250 El Camino Real #204
Tustin, CA 92780, USA
E-mail: sales@trgbiofilter.com
Contact TRG Biofilter
m
To TRG Biofilter Home Page
Technical Papers on Biofiltration
Reproduced with Permission
The technical papers listed below will provide an excellent overview of the
capabilities of biofiltration in reducing odorous and often toxic air pollutants. TRG
Biofilter and its academic associates were involved in all of the papers either as
writers or as project managers. Click on any of the titles for the full paper with
tables and illustrations.
1.
Biofiltration: An Old Technology Comes of Age.
Paper by F. Edward Reynolds, Jr. & W. D. Grafton III of TRG Biofilter. Published
in Environmental Technology, July/August 1999, pp 51-52.
Recent improvements in biofilter technology makes biofiltration air pollution control
technology a viable alternative to conventional approaches. Excellent survey
paper.
2.
Biological Air Pollution Control In North America.
Report on the USC-TRG Conference on Biofiltration, October 5-6, 1995, Los
Angeles, California. By George Skladany, Gero Leso, Douglas Hodge [Technical
Director of The Reynolds Group]
An overview of the state of the art of biofiltration in 1995.
3.
Modeling of Air Contaminants by Biofiltration.
Paper by Douglas S. Hodge, Member ASCE, Director of Bioremediation Services,
The Reynolds Group; and Joseph S. Devinny, Associate Member, ASCE,
Department of Civil. Engineering, University of Southern California. Published in
Journal of Environmental Engineering, Vol. 121, No. 1, January, 1995, by the
American Society of Civil Engineers (ASCE).
A definitive paper on the quantitative aspects of biofiltration. A mathematical
model was developed that describes basic transport and biological processes for
a biofilter. The model described transfer between the air and solids/water phases,
biological degradation of the substrate, CO2 production and accumulation, and pH
changes resulting from CO 2 accumulation. Model equations were solved using a
two-step, explicit, finite difference approximation technique, and solutions were
tested on simplified problems with known analytical results. Experimental data
were compared with the predictive model solutions for steady-state and nonsteady-state regimes.
4.
Biofilter Pilot Unit: A Case Study.
Section 10 of the Doctoral Thesis of Douglas Hodges at U.S.C. [Technical
Director of The Reynolds Group].
Large commercial bakeries can emit several hundred pounds of VOCs per day.
The known performance of biofilters for treating ethanol inspired the SCAQMD's
Technology and Advancement Office (TAO), Southern California Edison (SCE),
and Southern California Gas (SoCalGas) to jointly fund this biofilter pilot
demonstration project at a local commercial bakery.
5.
Full-Scale Biofilter: A Case Study.
Section 11 of the Doctoral Thesis of Douglas Hodges at U.S.C., later Director of
Marketing of The Reynolds Group (TRG).
A two-story open biofilter was designed to control VOC emissions, mostly ethanol,
from an investment casting process that releases VOC into the general working
area. Changes to SCAQMD rules, limiting maximum uncontrolled daily emissions
to 600 lbs per day, mandated the implementation of some form of VOC control.
6.
Biofiltration System to Remove Toxic and Odorous Gases from Wastewater
Treatment.
From a proposal by TRG Biofilter to the Ojai Valley Sanitary District.
Provides excellent overview of biofiltration. Includes technical background and
project description; diagram of proposed system; pilot scale emission test results;
environmental, technical & economic benefits; previous work by TRG Biofilter;
project plans; and references.
7.
Clearing the Air Biologically.
Paper by Joseph S. Devinny, M.ASCE and Professor of Civil and Environmental
Engineering at the University of Southern California. Published in Civil
Engineering, September 1998, pp 46-49, by the American Society of Civil
Engineers (ASCE).
Excellent survey paper with details on the Ojai Valley POTW project, which was
designed by TRG Biofilter. Across the country, an increasing number of
wastewater treatment plants are enlisting biofiltration to remove odor and
hazardous contaminants from air discharges.
8.
Treatment of Hydrocarbon Fuel Vapors in Biofilters.
Paper by Douglas S. Hodge, Victor F. Medina, Robert L. Islander, and Joseph S.
Devinny. Published in Environmental Technology, Vol 12, 1991, pp 655-662.
This paper reports on bench testing of biofilters using soil, carbon and
diatomaceous earth as support media for treatment of JP-5 jet fuel and diesel fuel
vapors. Activated carbon supported higher biodegradation rates than soil, and
diatomaceous earth was least effective. Jet fuel was degraded more rapidly than
diesel fuel.
9.
Biofiltration of JP-4 Jet Fuel Vapors.
Paper by Ann N. Chang and Joseph S. Devinny, University of Southern California.
Bench scale experiments were conducted to evaluate the effectiveness of
biofiltration for treating JP-4 jet fuel vapors from soil vapor extraction. Three
biofilter columns were operated, using granular activated carbon, bark compost,
and yard waste compost as packing materials. For the yard waste compost
biofilter, acclimation was slow and medium compaction occurred, but excellent
removal efficiency (>99%) was achieved.
10. Biofilter Treatment of JP-4 Vapors from a Soil Vapor Extraction System.
Demonstration Project by TRG Biofilter and Black & Veatch.
Excerpts from a proposal by TRG Biofilter to study removal efficiency as a
function of concentration and as a function of vapor contact time.
11. Biofilter Performance Report, March Air Force Base.
Report prepared by TRG Biofilter for Black & Veatch, Irvine, CA.
During the period from August, 1995 to April, 1996, a full scale biofilter was
applied to treat jet fuel air vapors that were emitted from an enhanced soil vapor
extraction system at March Air Force Base, Site 18. During the testing period,
removal efficiencies were measured independently by the University of Southern
California as frequently as once per week. Removal efficiencies reached greater
than 90%.
12. Final Report on Performance of a Pilot Scale Biofilter for Treatment of MIBK.
Report submitted by TRG Biofilter to Metromedia, Los Angeles, CA.
Includes analytical results from December 1995 thru January 1996. The report
states that a 90% removal efficiency can be achieved with a 93 second air flow
residence time. With a residence time of 47 seconds, a removal efficiency of 68%
is achieved.
13. TRG Biofiltration Vapor Treatment Systems Overview.
From a proposal by TRG Biofilter. This document covers technical fundamentals
and presents applicable TRG Biofilter models.
TRG Biofilter
Turnkey Biofiltration Systems
Tel: (714) 730-5397
Fax: (714) 730-6476
m
250 El Camino Real #204
Tustin, CA 92780, USA
E-mail: sales@trgbiofilter.com
Contact TRG Biofilter
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