1. BIO-FILTRATION
A Detailed Study of Methodology of Bio filtration In Controlling Air Pollution.
Shreyash Gupta
Avichal Sharma

2. OVERVIEW-:
Industries, agriculture transport many more modern socio-economic practices pollute our environment.
Gas Biofiltration is a relatively new technology used to purify contaminated air from volatile organic and inorganic compounds VOC’S and VIC’S, aromatic compounds and other toxic and odorous compounds.
Our main aim is to study use of bio filters for controlling air pollution in industries having above mentioned pollutants.
The experience gained from monitoring exercise carried out during the last 25 years and adoption of appropriate strategy for air quality control have been discussed in this paper presentation.

3. Air pollution Statistics
Percentage %
Ref. 1

4. INTRODUCTION Bio filtration is air pollution control technique
Involves bio degradation of contaminants under the action of microorganisms diffused in a thin layer of moisture known as “BIOFILM”
Mainly used for elimination of malodorous gas emissions and low concentrations of Volatile Organic Compounds (VOCs).
The process of Bio Degradation is :
Organic Pollutant + O2   CO2 + H2O + Heat + Biomass

5. BRIEF TIMELINE OF DEVELOPMENT OF BIO FILTERS
1923
Biological methods were proposed to treat odorous emissions.
1955
Biological methods were applied to treat odorous emissions in low concentrations in Germany.
1960’s
Bio filtration was used for the treatment of gaseous pollutants both in Germany and US.
1970’s
Biofiltration is used with high success in Germany.
1980’s
Biofiltration is used for the treatment of toxic emissions and volatile organic compounds (VOCs) from industry.
1990’s
Today, there are more than 500 biofilters operating both in Germany and Netherlands and it is widely spreaded in US.

6. WHY IS BIO-FILTRATION IMPORTANT
Bioreaction is a green process
Thermal and catalytic control units consume large volumes of expensive fuel.
Bioreactors only use small amounts of electrical power to drive two or three small motors.
Normally, bioreactors do not require full-time labor and the only operating supplies needed are small quantities of macronutrients.
Combusting
any fuel will generate oxides of nitrogen (NOx), particulate matter, sulfur dioxide (SO2), and
carbon monoxide (CO). Bioreactors usually do not generate these pollutants or any hazardous
pollutants

7. TYPES OF BIO FILTERS ON THE BASIS OF LAYOUT ON THE BASIS OF SHAPE
Open Bed : Uncovered and Exposed to all Weather conditions.
Closed Bed : Enclosed with a small exhaust port for venting of cleaned air
ON THE BASIS OF SHAPE
Horizontal :
With Larger footprints
Relatively inexpensive
Easy maintenance
Vertical :
Designed to reduce the footprint required.
Use less surface area compared to Horizontal
Expensive
Not easy to Maintain
ON THE BASIS OF SUPPORT MEDIA
Compost Bio Filter : Soil , Peat, Compost material is used
Synthetic Bio Filter : Ceramic , Plastic ( BTX )*

8. HOW DO BIO-REACTORS WORK ?
Microbes’ life cycle –they breed, feed, eat, die. Their diet is based primarily on carbon-based compounds, water, oxygen (for aerobic reactions) and macronutrients.
Mass flow diagram of a bio-reactor

9. SCHEMATIC DIAGRAM OF A BIOFILTER UNIT
Ref. 4

10. Horizontal Flat Bed Bio Filter Vertical Bio Filter
Ref.5

11. COMPONENTS OF A BIO-FILTER UNIT
MATERIALS used for bed media - peat, composted yard waste, bark, coarse soil, gravel or plastic shapes ( Reference 2 from EPA PDF )
Oyster shells (for neutralizing acid build-up) and fertilizer (for macronutrients) are mixed with bed media.
SUPPORT RACK -perforated - allow air from the plenum to move into the bed media -to contact microbes that live in the bed.
Perforations also permit excess, condensed moisture to drain out of the bed to the plenum.
FAN - used to collect contaminated air
As the emissions flow through the bed media, the pollutants are absorbed by moisture on the bed media.
Microbes reduce pollutant concentrations by consuming and metabolizing pollutants. During the digestion process, enzymes in convert compounds into energy, CO2 and water.
Material that is indigestible is left over and becomes residue.

12. Design and Performance Parameters
Contact Time and Air Flow
Moisture Content
Temperature
Siting
Media
Microorganism Seeding
Construction
Weeds
Rodents
Health and Safety Concerns
Costs

13. DESIGN AND PERFORMANCE PARAMETERS
TEMPERATURE: Most microbes can survive and flourish in a temperature range of 60 to 105 /F (30 to 41/C) (Ref. 3 of EPA PDF).
When emissions are too hot, humidifiers are used which cools gases down by evaporative cooling.
MOISTURE: Moisture creates the bio-film that removes (absorbs) pollutants from an air stream so that they can be assimilated by microbes.
Humidifiers made from an old FRP (fiber reinforced plastic) tank are used to increase moisture.
CARE AND FEEDING : Microbes need a diet of balanced nutrients to survive and propagate. Pollutants provide the main source of food and energy, but microbes also require macronutrients to sustain life.
Microbes use nitrogen to build cell walls.
some nitrogen products form water-soluble compounds and are leached out of the system with condensing water.
Nitrogen, phosphorus, potassium added by incorporating agricultural fertilizer into bed media.
It is important to monitor bed temperature at least daily, but every eight hours would be safer.
Moisture: The design should include
several rows of pipes near the top of the vessel with spray heads installed along their length, and
on/off valves on each pipe run to provide some control of humidity.
It is important to remember that a by-product of a bioreaction is water. If emissions are
saturated entering the process, there will be water condensing in the bed media. Always provide
space in the plenum for water to collect and a method to remove it from the plenum.

14. ACIDITY: Most bioreactors perform best when the bed pH is near 7, or neutral.
hydrogen sulfide, organic sulfur compounds, and halogens (chlorine, fluoride, bromine and iodine) are acidic in nature and lower the pH.
Oyster Shells may be added to neutralize the pH.
a Dilute solution of soda ash (sodium carbonate, Na2 CO3) may be introduced by a garden hose periodically.
Ref. 6

15. BIOFILTERS EFFECTIVENESS
Odor and hydrogen sulfide reductions up to 95%.
Ammonia reductions up to 80%.
Uses Microorganisms
Absorbs And Oxidizes
VOC’s
VIC’s
Oxidisable Inorganic Gases and Vapors
Produces
Water, Carbon di oxide, Salts
Microbial Biomass

16. Air Waste/Component
Microorganism
Support
Ammonia
bacteria
Celine pellete
Compost + ACTIVETED Carbon
Perlite
Benzene
Ethanol
Hydrogen Sulphide
pseudomanas sp.
Sugarcane Bagasse
Wood Bark
Pig Manure
Methyl Acetate
Methyl Ethyl Ketone
Methyl Tert Butyl Ether
Nitrogen oxides
rhodococcus Sp.
Compost +activated carbon
Styrene
exophiala yeanselmei
Yard Waste
perlite
Toluene
pseudomonas putida
Peat
Xylene
bacteria + yeast
Cellulose
Ref.7

17. Bio-filteration Thermal Process Chemical Oxidation
Differentiation Between
Bio-filteration Thermal Process Chemical Oxidation
-By-Product is nitrogen oxides which causes ozone depletion and smog formation.
-requires additional natural gas for achieving high tempt hence increases CO2.
-operation and handling cost is high.
-Produce chlorine and chlorinated products.
-require precise temperature and pressure conditions.
-In chemical oxidations chemicals have to stored and handled.
-Only By-product is waste biomass. -Ambient Temperature and pressure process. -investment and operation cost are lower than other two.

18. BIOFILTERS A Viable Option
Effective at emission reduction.
Low-cost
Biological system requiring management.
Design, installation and operation will impact building ventilation and bio-filters effectiveness.

19. COMPARISON OF BIOFILTERS AND OTHER TREATMENT PROCESSES
Ref.2

20. GAS FLOW RATE (in cfm)
Ref.3

21. Review of RESEARCHES
In research on Transient Behavior of Biofilter , Marc A. Deshusses describes the aerobic biodegradation of VOC mixtures from effluent air streams in laboratory scale compost based biofilters.
Bio filters had degraded and absorbed Hexane , Acetone , MIBK , propane and MEK in different proportions.
Established a fundamental description of pollutant removal in biofilters.

22. BIOFILTRATION-AN INNOVATIVE TECHNOLGY FOR THE FUTURE
-by Dr. Rakesh Govind, Prof. Chemical Engg. Department University of Cincinnati, OH
different types of biofilters’ support media
the various biofilters operations adopted in industry.
waste compounds treatable by biofiltration
commercial potential of biofiltration.
The paper concludes that when compared to other available technologies, biofilters have significant technical and economical advantages.

23. Photograph of four Biofilters being installed in Arlington, TX
At Central Regional Wastewater System Plant

24. A FEW EXISTING BIO FILTERS
McMinnville, Oregon: The installation in McMinnville, Oregon perhaps best demonstrates the capabilities as the levels of odorous compounds to be treated were among the highest ever reported from the wastewater treatment environment.
Long Sault, Ontario: Although a small (1500 cfm), indoor, container-type system, this installation demonstrates several key aspects that are relevant to any installation.
Sarnia, Ontario: This biofilter was installed in 2001 and treats 12,500 cfm of air coming from a sludge liming and drying operation.
Brookfield, P.E.I. : This biofilter was installed in 2002, at a composting plant in P.E.I., that treats 60,000 cfm of air from the composting process.
Toronto, Ontario: This biofilter was installed in 2002 in the north end of Toronto at the Toronto Mixed Waste Recycling and Organics Processing Facility.

25. REFERENCES:-
Review Paper on Biofiltration of Volatile Organic Compounds (VOCs) – An Overview by Thakur Prabhat Kumar, Rahul, Mathur Anil Kumar and Balomajumder Research Journal of Chemical Sciences ISSN X Vol. 1(8), 83-92, Nov. (2011); ref. 4
Magazine paper on Biofiltration: an innovative technology by Dr. Rakesh Govind, chemical engg., University Of Cincinnati, OH (2000) ref. 2, ref. 3
Journal on Environmental Progress vol. 24 no.23 (october 2005) by American Society of Chemical Engineers Project No. 98-CTS-4 Bureau of Sanitation, LA ref. 6, ref.7
Indian Journal Of Biotechnology vol. 2, july 2003, Biofiltration-an emerging technology by Soccol, Woicieschowski, Vedanberghe, Soares and Neto UFPR, Federal university of Parana, Curtiba-PR, Brazil CEP ref.5
Pollution statistics from Indian Journal Of Biotechnology vol. 2, july 2003 case study of effluent in Industries of Delhi-NCR region ref.1
Frederickson, J.; Boardman, C. P.; Gladding, T. L.; Simpson, A. E.; Howell, G. and Sgouridis, F. (2013). Evidence: Biofilter performance and operation as related to commercial composting. Environment Agency, Bristol.
EPA handout Environmental Protection Agency “What is Biofilter?”; “Using bio-filters to control air pollution”.