An assessment of the VOC removal efficiency of a soil vapour extraction (SVE) biofiltration unit.

1. BIOFILTRATION FOR TREATMENT OF
VOLATILE ORGANIC COMPOUNDS
Prepared by:
Graham Brown
Isabella Luu
Prepared for:
Roger Saint-Fort, Ph.D. P.Ag.
Environmental Chemist
December 2, 2016

2. 1 | P a g e
Executive Summary
A small-scale biofiltration system was set up in the Mount Royal University Environmental Sciences
laboratory to be analyzed by Environmental Science students, Graham and Isabella under the guidance
of Dr. Roger Saint-Fort. This project was undertaken to aid in the understanding of bioremediation
technologies utilized in the field for the treatment of contaminants, specifically the employment of
biofiltration systems. Contaminants to be analyzed by such technology are induced by anthropogenic
activities.
The scope of work involved constructing, maintaining, and analyzing various operating parameters to aid
in optimizing the biofiltration system. The construction, set-up, and analysis of the biofiltration
functioning and treatment of contaminants took place between October 19 to November 23, 2016. The
airflow distribution system required to enhance the biofilter system operation was operated on October
27 on continuous mode, up until November 7 where the system was subsequently operated in pulse
mode and operation was shut-off on November 18. Initial and final analytical tests were conducted on
October 19 and November 23, respectively.
Inlet VOC concentrations were reduced from greater than 2000 ppm to a steady state of 28.8 ppm over
the systems operational period. With sufficient run time under pulse mode operation, the system would
likely reduce the VOCs to nominal levels. The loading rate and inlet concentration trends mirrored each
other, while no identifiable trend was observed in the mass removal rate. Overall, the system removed
0.07% of the original contaminant by weight. This is rationalized despite the significant drop in VOC
levels due to the focus of the system on lighter fractions. Optimizing the temperature, nutrient content,
and airflow rate would benefit the system operation as this would allow for a greater percentage
removal of heavier fractions and continued success in light fraction removal.
With the production of this laboratory experiment coupled with a comprehensive study of the scientific
literature of preceding biofiltration studies, it is recommended that biofiltration systems be fully
optimized considering the above parameters as it provides the critical success factors required in
operating a full-scale system in the field. It is also recommended that other remediation technologies
like a carbon adsorption system or soil vapour extraction (SVE) be employed in the field along with the
biofiltration system to further aid in compliance with pertinent guidelines and regulations.
Respectfully Submitted,
Graham Brown
Environmental Science Student
Isabella Luu
Environmental Science Student

3. 2 | P a g e
Table of Contents
Executive Summary 2
Terminology and Acronyms 4
1.0 Introduction 5
2.0 Background 5
2.1 Biofiltration technology 5
2.2 Biofiltration system parameters 6
2.2.1 Air flow rate 6
2.2.2 Bulk density 6
2.2.3 Temperature 6
2.2.4 PH 7
2.2.5 Moisture content 7
2.2.6 Nutrient content 7
2.2.7 Packing materials 7
3.0 Scope of Work 7
3.1 Project aims and objectives 7
3.2 Project summary 8
4.0 Methodology 8
4.1 System design 8
4.2 Materials 9
4.3 Data collection 10
4.4 Quality assurance/quality control 10
5.0 Results 10
5.1 Inlet/outlet concentrations 10
5.2 Volumetric loading rate 11
5.3 Removal efficiency 12
5.4 Mass removal 13
6.0 Discussion 13
6.1 Data evaluation 13
6.1.1 Inlet/outlet concentrations 13
6.1.2 Volumetric loading rate 14
6.1.3 Removal efficiency 14
6.1.4 Mass removal 14
6.2 System optimization potential 15
7.0 Conclusions 15
8.0 Recommendations 15
9.0 Closure 16
10.0 Limitations 16
References 17
Appendix-A 18
Appendix-B 20

4. 3 | P a g e
Terminology and Acronyms
Bench Scale Testing is a small laboratory experiment designed to establish proof of concept and
determine viability of upscaling
Bottom-loaded is a biofiltration unit design choice where the inlet to the system is placed at the bottom
of the filter media and contaminants move upwards against gravity through the system
Elimination Capacity (EC) is the mass of contaminant degraded per unit volume over a defined unit of
time
Inlet is the port where the reading of the contamination is recorded, located prior to entering the filter
media
Loading Rate (LR) is the mass of contamination entering the biofiltration system over a given unit of
time and per unit of volume
Outlet is the port posterior to the filter medium where residual contaminant concentrations can be
recorded
Packing Material are the constituents that make up the biofilter medium
Pulse Mode is the operation of a system with pauses as opposed to continuously running the system
Steady State is when the recorded VOC concentrations stop decreasing and remain constant over a
period of time
Surface loading is the volume of gas per unit area of filter material per unit time
Top-loaded is a biofiltration unit design choice where the inlet to the system is placed at the top of the
filter media and contaminants move downwards with gravity through the system
VOC is a Volatile Organic Compound that is a naturally occurring or anthropogenic compound with high
vapor pressure that is prone is evaporating or sublimating in the air from a solid or liquid state

5. 4 | P a g e
1.0 Introduction
This report presents the results gathered from a biofiltration system set-up at Mount Royal University in
the Environmental Sciences laboratory. Under the guidance of Dr. Saint-Fort, Graham and Isabella are to
establish proof of concept of the removal of VOCs using bioremediation technology, for which a
biofiltration system was chosen as a removal method of interest. The construction, set-up, and analysis
of the biofiltration functioning and treatment of contaminants took place between October 19 to
November 23, 2016. The materials used to construct the bench scale biofiltration system were provided
in the laboratory by Dr. Saint-Fort.
2.0 Background
2.1 Biofiltration technology
Anthropogenic hydrocarbon contaminants can be treated in-situ by the use of bioremediation
technology. Bioremediation technology that has been employed for contaminant removal includes the
use of biotrickling filters, bioscrubbers, and biofilters (Devinny et al., 1999). Biofiltration incorporates
the use of a biofilter media typically comprised of a mixture of active and inert materials such as
vermiculite, sands, and organic matter (Doble and Kumar, 2005; Devinny et al., 1999). A generalized
schematic of a biofiltration system is shown below in Figure 1.
Figure 1. Schematic diagram of a general biofilter system (Delhomenie and Heitz, 2005)
Hydrocarbon contaminants within a soil system can undergo volatilization, causing vapors to be
discharged into the surrounding area and affect various human and ecological receptors. A myriad of
studies demonstrates that biofiltration systems are effective in the treatment of low concentration VOCs
from petroleum derived liquid contaminants (Devinny et al., 1999).

6. 5 | P a g e
Biofiltration as a means of a remediation technology is associated with generally low operating costs and
can be used as an alternative to conventional physical and chemical treatment methods. Advantages of
biological treatment include: low risk of chemical release into the environment and minimal energy
requirements (Wang and Govind, 1997). Secondary waste streams are minimized by microbial oxidative
and reductive activity leading to the release of less harmful products including carbon dioxide, water
vapour, and biomass (Wang and Govind, 1997; Kumar et al., 2011; Alonso et al., 1998).
2.2 Biofiltration system parameters
Within the biofilter media, absorption, adsorption, degradation, and desorption processes contribute to
the removal of contaminants (Devinny et al., 1991). Packing material parameters include: the degree of
compaction, water retention capacity, pore space volume, and the type and amount of microorganisms
present in the media (Devinny et al., 1999). Additional performance parameters required to be
optimized include air flow rate, nutrient content of the medium, temperature, pH, moisture content and
the packing material composition.
2.2.1 Air flow rate
Studies indicate that there are two rates that must be adjusted to optimized levels to obtain efficient
removal, this includes the transfer rate of VOCs from gas phase to the biofilter medium and the
biodegradation rate of VOCs within the medium (Delhomenie and Heitz, 2005). Further, the properties
of the compost material provide relatively large surface areas for contaminants to adhere to and flow
through the system while the addition of nutrients can be applied for optimization (Devinny et al.,
1999). Typical ranges for air flow rate is between 50-300,000 m3
h-1
; however, inlet flow rates are ideally
operated between 100-100,000 m3
h-1
(Deshusses, 1994; Detchanamurthy and Gostomski, 2012). It is
shown that the gas residence time in the biofilter medium depletes when the air flow rate is higher than
optimal rates; hence, this is not ideal as microbial biodegradation is not able to meet its maximum
potential (Detchanamurthy and Gostomski, 2012).
2.2.2 Bulk density
A method for optimizing the packing material porosity can be done so by mixing the biofilter medium.
Mixing allows for the medium to exhibit more pore space that allows for the adherence of
contaminants, hence decreasing the degree of compaction which allows for a more distributed flow
throughout the system (Bohn, 1992). Greater pore space attributes to the increased permeation of
contaminant air flow through the system.
2.2.3 Temperature
It is shown that increasing the temperature by 10°C, increases the degradation by 2-fold within the
optimal range of 25°C to 40°C (Deeb and Alvarez-Cohen, 1999; Wang and Govind, 1997). When
operating a biofilter on a large-scale, it is subject to variable temperature fluctuations. When operating
in cold temperatures, such as that exhibited during winter, it is important that the system is well
insulated to prevent heat loss within the system; however, it is suggested that the system is operated in
relatively warmer conditions to decrease the costs associated with additional insulation. For in-situ
operations, cold temperatures can lead to the condensation of moisture, filling the pore space and
preventing the transfer of contaminants out of the matrix.

7. 6 | P a g e
2.2.4 pH
The optimal pH range of a biofilter medium is typically a pH of 6 to 8, as it is shown to exhibit optimal
degradation rates, while influencing nutrient availability (Deshusses, 1994; Atlas and Bartha, 1993).
2.2.5 Moisture content
The typical moisture content value that is considered for optimal conditions of the biofilter medium is
60% by mass (Deshusses, 1994). In terms of compost, previous studies have shown that moisture
content values can range between 25-50% by mass (Ottengraf, 1987). Excess moisture content can fill
the pore space of the matrix and prevent the movement of VOCs through the system.
2.2.6 Nutrient content
Nutrient cycling in the biofilter medium aids in the distribution of microbial activity; hence, maintaining
sufficient microbial populations in the medium require nitrogen, phosphorous, and potassium nutrients
to initially be in the compost packing material (or added to the media). In terms of utilizing compost as a
packing material, it is suggested that nitrogen, phosphorous, and potassium be added at 0.4, 0.15, and
0.15% by mass of the compost material (Devinny et al., 1999); hence doing nutrient content tests at the
beginning of utilizing a biofiltration system is ideal so that the values can be adjusted throughout the
treatment duration.
2.2.7 Packing materials
The packing material chosen to be the biofilter media should be chosen while considering the
characteristics of the contaminant being run through the system (Detchanamurthy and Gostomski,
2012). The use of compost or peat as a medium to aid in biodegradation of VOCs is ideal in that it is
relatively low-cost and stable, which is beneficial when additional nutrients are being added to the
system to aid in removal (Devinny et al., 1999). Although biofiltration systems tend to exhibit relatively
low pressure drops, it is shown however that these packing materials can exhibit sedimentation and
compact when undisturbed, which could cause the pressure drop to increase (Yang et al., 2010;
Ottengraf, 1987). It is important to create turbulence and stir the medium as necessary so as to disrupt
the packing material so that removal can be more efficient, or ensuring that the filter bed material is
replaced every 3 to 7 years (Devinny et al., 1999).
3.0 Scope of Work
3.1 Project aims and objectives
This project aims to establish proof of concept of the removal of VOCs using a bench scale biofiltration
system. The construction, set-up, and analysis of the biofiltration functioning and treatment of
contaminants took place between October 19 to November 23, 2016.
The biofiltration system project objectives are as follows:
• To contaminant a soil matrix with a known quantity of petroleum derived contaminant in a soil
matrix and to set up a biofilter system to aid in the removal of the products released

8. 7 | P a g e
• To conduct analytical tests on the biofilter media and to assess parameters considered in the
optimization of the system throughout the duration of the study
• To quantitatively and qualitatively assess and report the amount of VOCs being removed from
the biofiltration system with a PID gas probe for a period of 3 weeks from October 27 to
November 18, 2016
• To provide recommendations based on the results drawn from the bench scale experiment
3.2 Project summary
A known volume of soil matrix is contaminated with a known volume of 87 octane gasoline. The
contaminated matrix is pumped through a storage vessel containing an active biofilm matrix composed
of fine sands, vermiculite, and compost. The VOC concentrations are monitored and recorded from inlet
and outlet valves built into the system between October 27 to November 18, 2016. The system was
monitored and run in both continuous and pulse modes over a period of 3-weeks, or for which the
contaminant has reached the desired concentrations as outlined in pertinent guidelines.
4.0 Methodology
4.1 System Design
PVC pipes were used to construct an enclosed air distribution system from the source of contaminant to
the inlet of the biofilter, and further attached to a carbon adsorption system where the remaining VOCs
were released to the atmosphere through the outlet. With regards to the carbon adsorption system
once at adsorptive capacity it must be reactivated so as to aid in the removal of remaining contaminants
in the affected system (Devinny et al., 1999).
The biofilter was bottom-loaded where air flow through the biofilter distributed the contaminants
upward through the packed medium. The contaminated vessel was constructed to mimic a vacuum
extraction well with reversed air flows. A mixture of fine sands, compost, and vermiculite was used as
the packing material within the filter. The bench scale operating parameters are outlined in Table 1 and
the instruments used are listed in Table 2. The system was run for multiple consecutive days during
continuous mode excluding weekends. When VOC inlet concentrations reached a steady state, pulse-
mode operation was initiated to enhance removal.
Refer to Appendix-A, Figure 1 and Figure 2 for system setup.

9. 8 | P a g e
Table 1. Summary of the bench scale biofiltration system operating parameters and average operating
values
4.2 Materials
Table 2. Summary of the instruments used in the operation, maintenance, and evaluation of the
biofiltration system
Manufacturer Product Name Serial Number
Cole Parmer Model L 115 Volt 60 Hertz 1.5 Amp Pump 79200-00
PE Photovac Photoionization Air Monitor 2020
Ever Bamboo Aquarium Filter Bamboo Charcoal n/a
Hach DR 5000™ UV-Vis Spectrophotometer 1432091
Agilent Technologies ADM 2000 Universal Gas Flowmeter US09E38752
Parameter Operating value
87 Octane gasoline (L) 0.03
Biofilter medium volume (m3
) 0.083
Biofilter medium weight (kg) 40.83
Contaminated soil volume (m3
) 0.011
Air flow rate (Lh-1
) 2.7x10-3
Operating temperature (°C) 20.2
pH 8.03
Water content of support medium (%) 44%
Empty bed retention time (years) 3.5
Bulk density (g/ml) 0.492
Phosphorous (% weight) 0.062
Nitrate (% weight) 0.83

10. 9 | P a g e
4.3 Data collection
Initial readings were taken at the start of the system runtime and final readings prior to shut down from
the outlet and inlet sampling points (Appendix-A, Figure 1). Readings were taken on fixed time intervals
from October 27 to November 18, 2016. The system was run in continuous mode on October 27, 28, and
31, followed by November 1st to November 4th. Once steady state was reached, the system operation
was switched to pulse mode on November 7, 14, and 18.
4.4 Quality Assurance / quality control
All instruments were calibrated prior to operation, and all glassware was cleaned and rinsed with
distilled water prior to use. In the analysis of nutrients. the photo spectrometer was standardized, and
the reference and sample cuvettes wiped with non-abrasive wipes to ensure maximum passage of light
through the matrix. Lab gloves were worn in the determination of bulk density to prevent the transfer of
oil from the users’ hands to the tin weigh tray.
Samples of the biofilter medium were taken at multiple depths within the system, from which sub
samples were taken from the composited material. The samples were assessed using weigh scales clear
of debris, with the initial and final weight of the weigh boats recorded during the transfer of soil
materials prior to evaluation.
The system was given five minutes to initialize prior to initial sampling. The PID was exposed to the inlet
for a minimum of one minute during each sampling event and the value was recorded once the
concentration had stabilized. The outlet sampling period was extended to five minutes prior to taking a
reading, due to the reduced rate of air flow.
A carbon adsorption system was utilized to which VOCs released from the biofilter was captured on the
reactive carbon medium. The carbon medium was heated at a temperature of 200°C to ensure that it
was reactivated and maintained its effectiveness in treatment of VOCs.
5.0 Results / Data Interpretation
5.1 Inlet/outlet concentrations
The VOC concentrations of the inlet exceed that of the outlet throughout the duration of remediation
on the first operating day i.e. October 27th, where the concentration is shown to decrease from 750
mg/L to 150 mg/L at a rate of 85.7 mgL-1
h-1
(Figure 2).

11. 10 | P a g e
Figure 2. The inlet and outlet VOC concentrations recorded on October 27th. Sampling occurred in 15
minute intervals over the span of 7 hours. The initial 10:00 am reading exceeded the detection limits of
the PID and was not included.
The initial readings peaked at 750 mgL-1
and 1039 mgL-1
on the first and second operating day,
respectively. The system entered a period of steady state after the fifth operating day with a minimum
reading of 28.8 mgL-1
. The final concentrations ranged between 150 and 16.4 mgL-1
on the first and sixth
operating day respectively. The mean outlet concentration was 0.47 mgL-1
across all sampling days
(Figure 3).
Figure 3. Inlet and outlet VOC concentrations taken on 10 operating days over a three-week time period.
The initial reading on the first operating day exceeded the detection limits of the PID and was not
included; therefore, the graph shows the second initial reading for the first operating day.
5.2 Volumetric loading rate
The initial loading rate of the system peaked at 24.4 and 33.7 mgL-1
hr-1
on the first and second operating
days. The lowest observed final reading was on the last day of operation at 1.3 mgL-1
hr-1
. The final
loading rate peaked at 4.9 mgL-1
hr-1
and finished at 1.3 mgL-1
hr-1
with a minimum of 0.53 mgL-1
hr-1
on the
ninth operating day. The system can be seen to enter a steady state on the fifth day of operation (Figure
4 and Figure 5).

12. 11 | P a g e
Figure 4. The loading rates observed on the first day of remediation. Sampling occurred in 15 minute
intervals over the span of seven hours. The initial 10:00 am reading exceeded the detection limits of the
PID and has not been included. The loading rate can be seen to decrease from 24.37 mgL-1
hr-1
to 4.87
mgL-1
hr-1
at a rate of 2.79 mgL-1
hr-1
.
Figure 5. The initial and final daily loading rates of the system observed over 10 operating days in a
three-week time period. The second inlet and outlet reading on the first operating day was used in place
of the initial readings due to exceeding the detection limit of the PID.
5.3 Removal efficiency
The net removal efficiency of the system including pre and post bamboo charcoal filter addition was
99.83% with a standard deviation of 0.36%. The mean outlet concentration was 0.47 mgL-1
. Prior to the
addition of the bamboo charcoal filter, the mean removal efficiency was 99.51% with a standard
deviation of 4.69x10-3
. The range in outlet concentrations was 0.00 mgL-1
to 3.50 mgL-1
.

13. 12 | P a g e
5.4 Mass removal
The mass removal during the initial run times peaked at 0.51 and 2.02 mg on the first and second
operating days with a minimum of 9.5x10-3
mg observed on the tenth. The final mass removal readings
peaked on the fourth and fifth operating days at 0.95 mg and 1.63 mg respectively. The range in mass
removed in all readings was between 0.0085 mg and 1.63 mg which occurring on the tenth and fifth
operating days. A total of 15.1 mg of the theoretical 22,000 mg of gasoline used to spike the system was
removed over the 10 operating days. This represents a net removal of 0.07% by weight (Figure 6).
Figure 6. The mass removal of the system observed over 10 operating days in a three-week time period.
The second initial inlet reading on the first operating day was used in place of the first reading due to
exceedance of the detection limit of the PID.
6.0 Discussion
6.1 Data evaluation
6.1.1 Inlet/outlet concentrations
The significant drop in inlet concentrations on the first operational day can be attributed to the high
availability of volatilized contaminant (Figure 2). Prior to running the system, the hydrocarbon is given
increased time to volatilize and pool relative to later in the system runtime when there is consistent
airflow within the contaminated headspace. This prevents pooling of VOCs and leads to significantly
higher initially readings. This is observed in Figure 3 on operating days 1 to 4 where the system was shut
off overnight and had time to pool between the initial and the final concentration of the day prior. This
phenomenon ends once the system has reached steady state and the proportion of the removed light
fractions is high.
The first initial data value of 750 mgL-1
on Figure 2 is significantly less than the 1039 mgL-1
reading the
day after (Figure 3). This is a result of utilizing the second reading on the first day taken 15 minutes later

14. 13 | P a g e
as it exceeded the 2000 ppm detection limit of the PID. The significant difference in VOC concentrations
is highlighted between initialization of the system and continued runtime.
6.1.2 Volumetric Loading rate
The results show that the loading rate progressively declined over the duration of remediation;
however, the VOCs released are not shown to completely diminish within the remediation time-frame
(Figure 4 and Figure 5). The downward trend in daily loading rate (Figure 5) correlates strongly to the
trends observed in inlet concentration (Figure 2). This is a result of loading rate being a function of the
VOC concentration within the waste air stream. As the concentration decreases, the quantity of
contaminant entering and interfacing with the packing filter media decreases. As result of this trend, the
presumption that is made is that there are various processes occurring within the biofilter media. Within
the limits of this experiment, it was not possible to definitively determine the rate at which the system
would reach an overloaded state.
Had the system operations prolonged and the loading rate underwent a significant drop at later stages
in remediation, the possible rationale is that the initial higher loading rates transferred a toxic level of
contaminant contributing to the damage of the biological components.
6.1.3 Removal efficiency
The removal efficiency of the constructed biofilter system is shown to be within the typical removal
efficiency of 60 to 100%, summarized in Appendix-B, Table 1. The significantly low VOC concentrations
at the outlet valve implies that the system exhibited efficient removal, such that VOCs were held within
the biofilter medium. Due to the addition of the activated carbon for capturing of excess VOCs from the
biofilter system, adsorption processes are likely playing a role in further removal.
Parallel to removal efficiency is elimination capacity (EC), which is the rate at which the contaminant
enters and is degraded within the system. The observed EC values were identical to that of the loading
rate in 68% of observations, where identical values shared a removal efficiency of 100%.
6.1.4 Mass removal
The mass removal of the initial observations exceeded that of the final observations on the first
operating day (Figure 6). This can be attributed to the concentration of VOCS in the air stream being
exceedingly high, allowing the transfer and breakdown of contaminants relative to lower concentration
over greater time periods.
Given the time span of 10 operating days no definitive trends in the rate of mass removal were
observed. Day three of operation was commenced after two days of rest as the system was not in
operation over the weekend. It is observed that during this time, the mass removal rate had declined
relative to the previous operation days that ran in succession. Higher mass removal rates would
normally be expected when the contaminant was given time to pool. This rebuke in the expected trend
is reinforced between days eight and nine where twice the resting days between sampling occurred;
however, the mass removed dropped only to rise after the next pulse-mode reading (Figure 6).
Despite the relatively short run period of the experiment, only 0.07% by weight of the original
contaminant was removed. This can be attributed to the difficulty in extracting the medium and heavy
fractions from the contaminant relative to the lighter fractions. This is due to the decreased vapor

15. 14 | P a g e
pressure associated with heavier fractions resulting in low transfer to the gas stream and subsequent
biofilter system.
6.2 System optimization potential
Flow rate is the parameter where optimization is most needed as the current flow rate is significantly
lower than that described in the literature. This would have a significant impact on the loading rate and
mass removal of the system. As the desired system parameters vary by system due to differences in
packing material media and contaminant, the flow rate would have to be carefully adjusted to prevent
overloading of the system.
The temperature of the waste air streams is a significant factor in the volatilization of contaminants and
the degree of fraction removal. The current system is limited by ambient temperatures within the
contaminated soil matrix. Elevating these temperatures would provide the necessary energy to remove
greater fractions of the contaminant from the soil matrix and allow for a greater percent removal rate.
The nutrient contents of the system were found to be 208% and 16% of the recommended nitrate and
phosphorus concentrations, respectively. The nutrient content is a key factor in maintaining the biofilm
within the packing material and degradation capability of the system. Optimizing the system nutrients
would likely lead to overall increases in the mass removal of the system.
7.0 Conclusions
Over the three-week sampling period the system was able to remove a significant concentration of the
volatilized contaminants. The system has excelled in the removal of light fractions; however, a
significant quantity of the remaining fractions still resides within the contaminated matrix. Provided
sufficient time, the system could reasonably be expected to reduce and the breakdown the emitted VOC
concentrations to near zero levels.
It is important to note that the results gathered from biofiltration bench scale studies under controlled
laboratory conditions may not be the same as those determined in the field due to various dynamic
factors that include seasonal temperature and relative humidity differences, particulates in the system
or atmosphere, and the loads being encountered at the inlet (Devinny et al, 1999).
8.0 Recommendations
It is recommended that various removal technologies be employed along with the biofilter system to
enhance removal rates, and in fact it is often required for compliance with regulatory standards
(Devinny et al., 1999). In the short term, it is recommended that physical treatment incorporates mixing
of the packed medium to redistribute biomass to prolong the system functioning (Berenjian et al.,
2012).
When a biofiltration system is implemented and applied in the field, the system should be periodically
monitored as needed to ensure proper functioning and that the critical success factors of the biofilter

16. 15 | P a g e
are optimized. When VOC inlet concentrations reached a steady state, pulse-mode operation should be
initiated to enhance the removal of the remaining contaminants within the system.
9.0 Closure
This report has been prepared in accordance with the information in the literature and the guidance of
Dr. Saint-Fort. The results and conclusion that have been derived in this report are specific to the
parameters outlined in the method and may not apply to other scales or operating conditions.
10.0 Limitations
The following limitations apply but may not be limited to:
• The results indicated in this report are obtained from a pre-constructed biofilter system from
• previous years with preceding Environmental Science students conducting a biofiltration study;
hence the values obtained from the inlet and outlet values may be effected from prior use.
While efforts were made in substantiating this study in the provided time frame and materials
provided, Graham and Isabella cannot guarantee the accuracy of the results presented
• Confirmatory samples were not taken due to the nature of this study, but it is important to note
that it is required as a compliance measure to pertinent guidelines and regulations
• The report provides proof of concept and is not comprehensive in terms of field construction
and development of a full-scale system as it would be subject to the intricacies of the
environment
• This report is for the exclusive use of Dr. Saint-Fort

17. 16 | P a g e
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(VOCs) – An overview. Research Journal of Chemical Sciences, 1(8), 83-92.
Http://dx.doi.org/10.1007/s11157-012-9288-5
Ottengraf, S. P. P. (1987). Biological systems for waste gas elimination. Trends in Biotechnology, 5(5),
132-136. Http://dx.doi.org/10.1016/0167-7799(87)90007-2
Wang, Z., & Govind, R. (1997). Biofiltration of isopentane in peat and compost packed beds.
Environmental and Energy Engineering. 43(5), 1348-1356.
Http://dx.doi.org/10.1002/aic.690430524

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Appendix-A
Figure 1. Bench scale biofiltration system set-up

19. 18 | P a g e
Appendix-A
Figure 2. Bench scale biofilter system attached to a small-scale carbon adsorption system comprised of
activated bamboo carbon
Biofilter
Medium
Contaminated
Vapour Inlet
Carbon Adsorption Filter

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Appendix-B
Table 1. Biolfilter parameters for operating conditions of waste air treatment derived from Deshusses, M.
A. Biodegradation of Mixtures of Ketone Vapours in Biofilters for the Treatment of Waste Air, Ph.D.
thesis, Swiss Federal Institute of Technology, Zurich, 1994.
Parameter Typical Operating value
Biofilter layer height 1 m
Biofilter area 1 – 3000 m2
Waste air flow 50 – 300,000 m3
h-1
Biofilter surface loading 5 – 500 m3
m-2
h-1
Biofilter volumetric loading 5 – 500 m3
m-3
h-1
Bed void volume 50%
Mean effective gas residence time 15 – 60 s
Pressure drop per meter of bed height 0.2 – 1.0 cm water gauge (max. 10 cm)
Inlet pollutant and/or odor concentration 0.01 – 5 g m-3
, 500 – 50,000 OU m-3
Operating temperature 15 – 30 °C
Inlet air relative humidity > 98%
Water content of the support material 60% by mass
pH of the support material pH 6 – 8
Typical removal efficiency 60 – 100%
Table 2. Physical properties of the hydrocarbon octane, C8H18
Properties Values
Density 0.703 gm cm-3
(at 20°C)
Vapor pressure 1.33 kPa (at 20.0°C)
Flashpoint 13.0°C
Viscosity 0.5151 cP (at 25°C)