1. CIV E 657: Air Pollution Control
Instructor: Dr. Zaher Hashisho
Presented by:
Monisha Alam
Controlling Emission of Volatile Organic
Compounds by Biofiltration: Case Study of
a Printed Circuit Board Industry in Canada

2. 2
OUTLINE
• Objective
• Volatile organic compounds (VOCs) emission in Canada,
health and environmental effects of VOCs
• Traditional VOCs removal technologies and limitations
• Biofiltration: a new application in removal of VOCs
• Biofiltration operational considerations, advantages, cost
and limitations
• Case study of a printed circuit board (PCB) industry located
in Toronto, Canada
• Conclusion and recommendations

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OBJECTIVE
• To introduce biofiltration, a green technology applied
recently for efficient VOCs removal from industrial
airstream
• To perform a detail case study on VOCs removal by a
commercial scale biofiltration system in a printed circuit
board (PCB) industry located in Toronto, Canada

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VOCS EMISSION RATES IN CANADA
Major sources of VOCs emission: industrial activities involving
paints, solvents, lubricants, greases etc. (Fiedler et al. 2005)
• in 2014, 2.2 Mt
(approx.) VOCs
emission in Canada.
• highest emission:
industrial sources -
40% (860 kt) of total
emissions
Air Pollution Emission Inventory (APEI) Report:
http://ec.gc.ca/Air/default.asp?lang=En&n=89ED82E9-1&offset=8&toc=show
http://www.conferenceboard.ca/hcp/details/environment/voc-emissions.aspx

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VOC EMISSION IN ALBERTA
Emission reduction in
AB: significantly lower
than other provinces
VOCs source in AB:
Industrial sources: largest
contributor
Environment Canada 2001a
Environment Canada 2001a

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ADVERSE EFFECTS OF VOCs
Health
Eye & skin
irritation
Respiratory &
heart diseases
Central nervous
system damage
Carcinogenic
effects
Environmental
Atmospheric
ozone formation
Acid rain
Vegetation
damage
Greenhouse gas
formation
Formation of Photochemical
Smog
(Fiedler et al. 2005)
Google image

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VOC REMOVAL TECHNIQUES
Traditional technologies used:
• Incineration
• Carbon adsorption &
absorption
• Chemical scrubbing
• Condensation
• Membrane separation
• Zeolite adsorption
(Khan and Kr. Ghoshal 2000, Moretti 2001)
Disadvantages:
• High energy
consumption
• Costly if VOCS in low
concentration
• fuel burning –
greenhouse gas
emission
• Cross-media pollutant
transfer

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BIOFILTRATION: A RECENT VOC REMOVAL
TECHNOLOGY
(Fulazzaky et al. 2014)
Contaminant intake Digestion & Metabolism Non-toxic end
products (CO2, H2O)
Working Principle:
• VOCs laden air passed through porous filter media supporting
microorganisms
• VOCs adsorbed from air phase to water/bio-film phase
• Adsorbed VOCs are decomposed through bioreaction
Image Source: Google Image

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BIOFILTRATION SYSTEM
A sketch of a typical Biofiltration system
(Khan and Kr. Ghoshal 2000)

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ADVANTAGES OF BIOFILTRATION OVER
OTHER VOC REMOVAL TECHNOLOGIES
• Low Cost Technology
• No expensive fuel required
• Least energy consumption
• Easy & Simple
• No complex mechanical parts
• Filter media & microorganisms: available in nature
• Typically used filter media: wood, compost, peat, soil etc.
• Eco-friendly Technology
• No fuel burning – no emission, treats low concentration VOCs
• No toxic end products
Technology Cost (USD/106
cft air)
Incineration 130
Ozone 60
Carbon adsorption 20
Biofiltration 8
(Wani et al. 1997)
(Wu et al. 1999)

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DESIGN CONSIDERATION & LIMITATION
To consider
• Filter Bed Properties
• Void fraction
• Surface area
• Water retention capacity
• Contaminant Property
• Biodegradability complex bonds: resist bioreaction
• Toxicity Microbial death
• Microbial Growth favourable environment required
• Moisture content Clogging of pores
• pH, Temperature neutral pH required
• Nutrients
• Oxygen content
Limitation
• Large space required
• Long treatment time
• Frequent change of filter bed
(Wu et al. 2006, Sempere et al. 2011)

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SUCCESSFUL APPLICATIONS OF
BIOFILTRATION IN VOCs REMOVAL
(Iranpour et al. 2005, Fulazzaky et al. 2013) http://www.pureairsolutions.nl/en/site/our-references
*BTEX: benzene, toluene, ethylbenzene and xylene
Industry Location VOCs removal efficiency
Petrochemical China BTEX*: 95%, total VOC: 90%
Chemical California, US Styrene: 70-85%
Painting California, US Total VOCs: 83-93%
Flexographic
Printing
Netherland 15,000 m3/h airflow, 40 ton VOCs
(Ethanol, ethyl acetate): >90%
Automobile Spain 30,000 m3/h airflow, 40 ton VOCs
(ethyl acetate, toluene), 95%
Electronics Toronto, Canada Ethylene glycol, acetate 5000 cfm,
125 ppm : >90%

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CASE STUDY: PCB INDUSTRY
(Shareefdeen et al. 2006)
Type of industry Printed circuit board manufacturing facility (PCB)
Location Urban area in greater Toronto, Canada
VOCs emission
source
• Solder masking process (solvent mixing, spraying of
masking agents on circuit board, infrared oven drying)
Emitted VOCs • Propylene Glycol Monomethyl Ether Acetate (PGMEA)
• 1,3,5 triazine-2,4,6 triamine, di-Propylene Glycol
• Monomethyl Ether (di-PGME)
VOCs concentration • Solder masking process air: 40 ppmv(airflow: 3500 cfm)
• Infrared drying oven air: 450 ppm (airflow: 1000 cfm)
• Chemical fume hood air: 500 cfm
• Combined air flow: 120 ppm (flow volume: 5000 cfm)
Type of filter used • Commercial biofilter (BASYSTM), capacity: 7500 cfm
Operation started • August, 2000

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CASE STUDY: PCB INDUSTRY contd..
(Shareefdeen et al. 2006)
Commercial scale 7500 cfm capacity biofilter system (BASYSTM)
at the printed circuit board manufacturing facility, Toronto, Canada

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CASE STUDY: PCB INDUSTRY contd..
(Shareefdeen et al. 2006)
Detail of Biofilter system used:
Two units of equal dimension (40' x 8' x 8') made with:
i) Wood-based media (BIOMIXTM)
ii) Inorganic media (BIOSORBENSTM): synthetically manufactured to give uniform
particle size (<1 inch), surface area 40.9 m2/gram media
Synthetic media
Structure:
• Inside Core : hydrophilic mineral
• Outside Coating : nutrient rich sorption material with binders
Pre-treatment • Wet Scrubber – provides humidification of air
• Scrubber configuration: polypropylene mist eliminator, steel baffle
Data Collection & Analysis
Data Collected from:
• Inlet to scrubber & filter
• Outlets of both filters
• Analysis: Gas Chromatography with Solid Phase
micro extraction method (SPME)
• Monitored: removal efficiency, pressure drop,
moisture content, microbial count, pH, temperature

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CASE STUDY: PCB INDUSTRY contd..
(Shareefdeen et al. 2006)
Results & Discussions
Media
dry out
RE > 90%
Figure: Removal efficiency, RE profiles of VOCs from
the commercial (BASYSTM) biofilter system
Initial drop in RE due to
media dry-out
System modification:
• Proper irrigation
• Nutrient spray
RE > 90%
Slight RE drop in
winter:
• Heat loss (from scrubber
& media)
Compensation design:
• Steam add to inlet air

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CASE STUDY: PCB INDUSTRY contd..
(Shareefdeen et al. 2006)
Results & Discussions
Table: Media environment of the commercial BASYSTM biofilter
• pH: acceptable range (6 to 8) for bacterial growth
• TMC: wood-media-initially higher, synthetic-media: increased later
• Moisture content: higher in wood-media

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CASE STUDY: PCB INDUSTRY contd..
(Shareefdeen et al. 2006)
Results & Discussions
• Targeted VOC (PGMEA) removal efficiency (RE) > 90%
• Removed non-targeted VOCs with efficiency > 80%
• total VOCs (350 ppm) and odour removal with RE > 80%
• Pressure drop: always < 1 inch water
• No biomass clogging problem
• Empty bed residence time (EBRT) in synthetic-media 50% less
than wood-media, due to high surface area

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CONCLUSION
• Good performance of commercial scale biofilter in VOCs
removal
• Composite filter bed with organic & inorganic media can
increase filtration efficiency due to controlled operation
• Biofiltration capital cost lower than traditional technologies
• Biofiltration highly cost effective in VOCs removal at very low
concentration
• Biofiltration efficient VOCs removal from various industrial
emissions such as printing, electronics, petrochemical etc.

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RECOMMENDATION
Biofiltration strongly recommended for Alberta industries because:
In Alberta, VOCs production in 2013: (NPRI) (Environment Canada, 2015)
• 443,250 tonnes by petroleum industry
• 23,575 tonnes from painting & and surface coating industries,
VOCs removal from AB industries by biofiltration-Recommendations
• In winter: prevent filter media heat loss by steam addition
• Routine maintenance of filter bed material to avoid moisture
clogging due low temperature
• pH & temperature control for proper microbial activity
• Pre-treatment of pollutant air for highly toxic VOCs
NPRI: National Pollution Release Inventory

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REFERENCES
• Iranpour, Cox, Deshusses, Schroeder. Literature Review of Air Pollution
Control Biofilters and Biotrickling Filters for Odor and Volatile Organic
Compound Removal, Environ Prog, 2005, 10, 24 (3), 254-267.
• Zhao, Huang, Wei. A demonstration of biofiltration for VOC removal in
petrochemical industries, Environ Sci : Processes Impacts, 2014, 16 (5),
1001-1007.
• Wu, Quan, Zhang, Zhao. Long-term operation of a compost-based biofilter
for biological removal of n-butyl acetate, p-xylene and ammonia gas from
an air stream. Biochem Eng J, 2006, , 32 (2), 84-92.
• Wu, Conti, Leroux, Brzezinski, Viel, Heitz. A high performance biofilter for
VOC emission control. J Air Waste Manage Assoc, 1999, , 49 (2), 185-192.
• Wani, Branion, Lau. Biofiltration: A promising and cost‐effective control
technology for Odors, VOCs and air toxics, Journal of Environmental
Science and Health Part A: Environmental Science and Engineering and
Toxicology, 1997, 08/01, 32 (7), 2027-2055.

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