In the first half of this year I was asked to investigate the potential passive air flow on two odour skid's. It was thought that the current media in the tank's could be changed out with more economical product. Before this could be determined the passive flows needed to be checked before and after the extraction fan.

1. Field Service Report
SFCXX1 / SFCXX2
Air Flow Testing Report
Flow Control Facilities
Completed by
David List
On behalf of CLIENT
July, 2016
Employed by Ventia
Work Order XXXXXXX

2. Field Service Report
SFCXX1 / SFCXX2 Flow Control Facility
Field Service Report
The aim of this report is to outline the procedure taken to identify the correct flow
rates through the odour filters. Then identify some improvements that “CLIENT” may
wish to implement to improve performance.
Contents
Work Order Request........................................................................................................................- 1 -
Air Flow Testing Procedure ............................................................................................................- 3 -
Testing Device..............................................................................................................................- 3 -
Testing Method.............................................................................................................................- 4 -
Testing Procedure........................................................................................................................- 5 -
SFCXX1.............................................................................................................................................- 6 -
As Constructed .............................................................................................................................- 6 -
Test Results ..................................................................................................................................- 7 -
Conclusion.....................................................................................................................................- 7 -
SFCXX2.............................................................................................................................................- 8 -
As Constructed .............................................................................................................................- 8 -
Test Results ..................................................................................................................................- 9 -
Conclusion.....................................................................................................................................- 9 -
Improvements .................................................................................................................................- 10 -
Odour Control Pre-Filters..........................................................................................................- 10 -
SFCXX1 Pre-Filters ...............................................................................................................- 11 -
SFCXX2 Pre-Filters ...............................................................................................................- 12 -
Airepure Australia...................................................................................................................- 13 -
Differential Pressure Transmitter.............................................................................................- 14 -
Air Flow Transmitter...................................................................................................................- 14 -
Conclusion.......................................................................................................................................- 15 -
References......................................................................................................................................- 15 -
Enquiries..........................................................................................................................................- 16 -

3. Field Service Report
- 1 -
Work Order Request
The following is a direct exert from an email sent by “CLIENT” to “VENTIA”;
From: CLIENT (EMAIL)
Sent: Tuesday, 31 May 2016 11:38 AM
To: VENTIA (EMAIL)
Subject: Work order 6345599
Hi VENTIA,
I am currently looking at replacing the carbon filter media at SFCXX1 and SFCXX2. To ensure that we
order the correct amount of carbon we need to know the air speeds through the carbon beds. Can you
please arrange for the following tests so that we can confirm airflows?
SFCXX1:
 Confirm what speed fan runs at, either run fan and take reading or confirm speed with
manufacturer.
 Measure airflow prior to fan without fan running. This is so we can see what passive airflows
are experienced on site. (If we have adequate airflow we will decommission the fan)

4. Field Service Report
- 2 -
SFCXX2:
 Confirm what speed fan runs at, either run fan and take reading or confirm speed with
manufacturer.
 Measure airflow prior to fan without fan running. This is so we can see what passive airflows
are experienced on site. (If we have adequate airflow we will decommission the fan)
Note that passive readings will need to be taken while the wet well pumps are not in operation.
If you have any questions, please let me know.
Regards,
CLIENT
Sewer Optimisation Technician
Lucknow St, Mitcham, Victoria 3132

5. Field Service Report
- 3 -
Air Flow Testing Procedure
To achieve accurate flow rates, the right testing equipment and procedure must be
used.
Testing Device
The device chosen was the FLUKE 922 Air Flow Tester.
The FLUKE 922 combined with the pitot tube is
capable of measuring “Velocity” and “Flow”.
The particular method that was used during the
testing is “Flow”. The flow unit used are m3/h.
Of course the flow values given in the testing are
directly related to velocity and can be converted via
the link below;
Air Flow Conversion
The table below shows the function and capabilities of the Fluke 922;
Please see full details in data sheet attached to this PDF.

6. Field Service Report
- 4 -
Testing Method
Air flow readings can be inaccurate due to small eddies and currents forming within
the flow path. More commonly referred to as “Turbulent” & “Laminar” flow, see
below;
To ensure that accurate readings are achieved, the pitot tube is traversed across the
depth of the pipe and then averaged over the sample time.
Traversing is a method where the measuring instrument is moved across the flow
path to ensure all flows can be measured accuracy. See below;
For more information on pitot tubes and traversing, please see link below;
Performing a Duct Traverse

7. Field Service Report
- 5 -
Testing Procedure
To ensure that all bases were covered, several tests were performed at different
operational times.
1. Ensure negative or neutral air flow
 INLET - Pump ON, Extraction Fan OFF
 OUTLET - Pump ON, Extraction Fan OFF
2. Ensure positive passive air flow
 INLET - Pump OFF, Extraction Fan OFF
 OUTLET - Pump OFF, Extraction Fan OFF
3. Confirm extraction air flow
 INLET - Pump OFF, Extraction Fan ON
 OUTLET - Pump OFF, Extraction Fan ON
All tests had a sample time of 1-minute. The MAX, MIN & AVERAGE readings were
then recorded. See example below;
NOTE: An accurate flow rate is achieved by combining the velocity with the diameter
of the pipe or duct. For each sample table I will list the size of the pipe so
conversions can be made if necessary.

8. Field Service Report
- 6 -
SFCXX1
As Constructed
Before conducting the air flow tests I contacted the manufacturer for the as
constructed drawings.
Aerotech were able to provide me with the original specifications to the extraction
fan, including the operating flow rate of 3510 m3/h @ 1.4KPa. See below;
The motor specifications were also confirmed via the name plate. See below;
See the full “AS CONS” attached to this PDF.

9. Field Service Report
- 7 -
Test Results
For each of the tests below the following applies;
Inlet Diameter = 500mm
Outlet Diameter = 400mm
Units = m3/h (cubic meters per hour)
Sample Time = 1 min (approximately)
Pump ON, Extraction Fan OFF
MAX MIN AVERAGE
INLET 0 0 0
OUTLET 0 0 0
Pump OFF, Extraction Fan OFF
MAX MIN AVERAGE
INLET 581 510 532
OUTLET 607 573 590
Pump OFF, Extraction Fan ON
MAX MIN AVERAGE
INLET 2594 1833 2318
OUTLET 3168 2054 2721
Conclusion
The readings above indicate that there is positive air flow through filter when the
pumps are OFF. Whether they are adequate for the new media cannot be confirmed.
The static outlet pressure, on TEST 3 was 170 Pa.
Whilst the specifications suggest the air flow is 3510
m3/h @1.4 KPa, this does not mean that it will operate
at 1.4 KPa.
The low operating pressure could mean that the media
install is just porous in nature. This could also indicate
that the pre-filters are blocked.

10. Field Service Report
- 8 -
SFCXX2
As Constructed
Before conducting the air flow tests I contacted the manufacturer for the as
constructed drawings.
Aerotech were able to provide me with the original specifications to the extraction
fan, including the operating flow rate of 1000 m3/h @ 1.4KPa. See below;
The motor specifications were also confirmed via the name plate. See below;
See the full “AS CONS” attached to this PDF.

11. Field Service Report
- 9 -
Test Results
For each of the tests below the following applies;
Inlet Diameter = 230mm
Outlet Diameter = 230mm
Units = m3/h (cubic meters per hour)
Sample Time = 1 min (approximately)
TEST 1 - Pump ON, Extraction Fan OFF
MAX MIN AVERAGE
INLET 0 0 0
OUTLET 0 0 0
TEST 2 - Pump OFF, Extraction Fan OFF
MAX MIN AVERAGE
INLET 136 95 117
OUTLET 149 99 127
TEST 3 - Pump OFF, Extraction Fan ON
MAX MIN AVERAGE
INLET 1185 1056 1118
OUTLET 812 677 747
Conclusion
The readings above indicate that there is positive air flow through filter when the
pumps are OFF. Whether they are adequate for the new media cannot be confirmed.
The static outlet pressure, on TEST 3 was 153 Pa. Whilst
the specifications suggest the air flow is 1000 m3/h @1.4
KPa, this does not mean that it will operate at 1.4 KPa.
The low operating pressure could mean that the media
install is just porous in nature. This could also indicate that
the pre-filters are blocked.
NOTE: I suspect that the INLET readings for TEST 3 were
compromised. I would suggest the more relevant reading
are from the OUTLET.

12. Field Service Report
- 10 -
Improvements
Odour Control Pre-Filters
Ensuring that the pre-filters are working efficiently is an essential part of the odour
control operation. The ideal installation would be as follows;
The first filter is a “Mist Eliminator”. This separates oil and water from the air, then
the condensate is exhausted via the drain.
The second filter is a “Particle Filter”. This further filters any large particles that are
not caught by the mist eliminator.
If these filters are not operating effectively, they can allow moisture to enter the filter
media a dramatically shorten its life span. A blocked pre-filter can also dramatically
reduce the permissible air flow.
To avoid excessive moisture, the condensation drain should be adequately
maintained so that water does not pool in the bottom of the duct.

13. Field Service Report
- 11 -
SFCXX1 Pre-Filters
The pre-filters for SFCXX1 feature only one
set of “Mist Eliminators”. I suggest the
missing filter was removed because of
possible back pressure issues or was
simply not replaced.
The “Mist Eliminator” is very dirty. It can be
washed but I suggest it be replaced.
The differential pressure across the pre-
filter was measured whilst the exhaust fan
was running. The reading was 1168 Pa.
With a clean filter you should only get a few
hundred pascals at the most. Suggesting it
is very blocked.

14. Field Service Report
- 12 -
SFCXX2 Pre-Filters
The pre-filters for SFCXX2 do not feature
“Mist Eliminators” and are visibly corroded.
These filters are called “V FORM” and are
acceptable if properly maintained. They are
designed to be “throw away” items.
Like the filter at SFCXX1, these filters are
also very dirty. The picture shows a
replacement date of the 26/9/14. They
should be replaced at least every 6
months.
The differential pressure across the pre-filter
was measured whilst the exhaust fan was
running. The reading was 986 Pa.
With a clean filter you should only get a few
hundred pascals at the most. Suggesting that
they are very blocked.

15. Field Service Report
- 13 -
Airepure Australia
Airepure was the company that installed the Odour Filters. I got in contact with Allan
Heckenberg who replied to me via email with the following suggestions;
Hi David,
Good chatting to you. Managed to find the data sheets pretty swiftly.
Data for the mist eliminators and Vform filters attached, see pressure drops for “new”. Fouled these
numbers should increase by about 150Pa at normal flow rates.
Given the pictures, I would change the V forms, and try to give the mist eliminators a power wash, if
they are not good, re-use till you can obtain some new ones from us. They are overseas units, so
figure about 10 weeks from order. The V form disposables are generally ex stock or a week at worst,
a bit longer for SST versions.
You would normally dump the pre filters every six months or so, the mist eliminators when they don’t
respond well to cleaning.
Media is expensive, but you get the performance life you pay for. Pressure drop across the bed
should be essential constant over time, even when exhausted chemically. Assuming the bed has not
been grossly contaminated by the pre filters failing – due to lack of maint.
Always happy to chat to the design folks, we can always offer a range of price points that actually
work, and let you know up-front the up and down sides of any of the media and solutions.
Cheers,
Dr Allan Heckenberg (PhD)
Business Manager
Airepure Australia Pty Ltd
64 Geddes Street, Mulgrave VIC 3170
PO Box 747, Mulgrave VIC 3170
www.airepure.com.au
See the full email and filter data sheets attach to this PDF.

16. Field Service Report
- 14 -
Differential Pressure Transmitter
I would suggest installing a differential pressure transmitter across the pre-filters.
Shown below is an ABB 266DSH Differential Pressure Transmitter;
By installing and monitoring the differential pressure across the pre-filters you will be
able to capture when the filters need replacing.
For further information, see link below;
ABB 266 Differential Pressure Transmitter - Data Sheet
Air Flow Transmitter
I would suggest installing an air flow sensor on the outlet pipe. Shown below is an
IFM SA4100 Flow Transmitter.
By installing and monitoring the air flow you can accurately identify if the correct
amount of air is being exhausted.
For more information, see link below;
IFM SAF4100 Flow Transmitter - Data Sheet

17. Field Service Report
- 15 -
Conclusion
The results show that both at SFCXX1 and SFCXX2 “Odour Filters” can operate
passively.
Though if this were to be introduced considerations would have to be made in
regards to the lack of air flow. By reducing the air flow this may have other corrosive
effects on the exposed equipment in the wet well (guide rails, pumps, chains etc).
I would suggest trailing the new passive odour control before remove any existing
equipment.
References
The following documentation is attached to this PDF;
 No References (CENSORED)

18. Field Service Report
- 16 -
Enquiries
Should you need any clarification on this document or if you wish to discuss
implementing any suggested improvements contact myself or Anthony Crowther.
David List
Mob: 0408 006 344
Email: David.List@ventia.com.au
Anthony Crowther
Mob: XXXX XXX XXX
Email: