BIO-FILTRATION

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 + O2CO2 + H2O + Heat + Biomass

5. BRIEF TIMELINE OF DEVELOPMENT OF BIO FILTERS

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.

7. TYPES OF BIO FILTERS • ON THE BASIS OF LAYOUT • 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. Vertical Bio Filter • Horizontal Flat Bed Bio Filter Ref.5

11. COMPONENTS OF A BIO-FILTER UNIT • MATERIALSused 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.

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. Ref.7

17. DifferentiationBetween 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. BIOFILTERSA 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. Deshussesdescribes 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. RakeshGovind, 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 onBiofiltration of Volatile Organic Compounds (VOCs) – An Overview by Thakur PrabhatKumar, Rahul, Mathur Anil Kumar and BalomajumderResearch Journal of Chemical Sciences ISSN 2231-606X 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 45221-0171 (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 81531-970 ref.5 • Pollution statistics from Indian Journal Of Biotechnology vol. 2,july 2003case 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”.