OEC Measurement to VDI Guideline 3885/1 and the Electronic Noses · 2014-05-27 · a big car...
Transcript of OEC Measurement to VDI Guideline 3885/1 and the Electronic Noses · 2014-05-27 · a big car...
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011
OEC MeasurementOEC Measurementaccording to the new VDI Guideline 3885/1
and the need for Electronic NosesThis material may be used &
distributed freely if cited correctly
Franz‐Bernd Frechen & Stefan M. Giebel, University of Kassel/Germany
Chair, IWA Specialist Group “Odour and Volatile Emissions”
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1 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
Chair, DWA Committee “Emissions of waste water facilities”
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Overview
Wh th d f Where the odour comes from ... ... and why we have to measure it in liquids: The Odour Emission
Capacity OEC – VDI 3885/1
Online Measurement of Sulphide and OEC: the Sulphide and Online Measurement of Sulphide and OEC: the Sulphide and OEC measurement Unit SOU – and that’s why we will need ...
El t i Electronic noses
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2 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Where does the odour come from?
Industry Sewer System, esp. pressure mains Wastewater and Sludge Treatment and Disposal
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3 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
g p
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011All starts in the sewer system
Odorants Odorantsemit from
Odorantsemit from Odour Odour
Odorants dischargedi t are pre-
sent in thewastewater
emit fromwastewaterinto the
sewer air
emit fromsewer
into am-bient air
impact inambientair
annoy-ance
into sewer
Odorants produced in sewer air bient air airproduced in the sewer
The consequence of this is that is is essential to measure the amount of odorants (and other compounds) in the liquid phase
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4 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Another reason why measuring the liquid is inevitable
A standard sewer with natural ventilation via the manholesA standard sewer with natural ventilation via the manholes ...Any kind of monitoring device (e.g. H2Sg)
( h h i h i h h l )(at whatever height in the manhole)
odour
l = low pressure areah = high pressure area
d odourhllh
odour
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5 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011A short detour to Sulphide/H2S
S l hid i d i t t d t ith Sulphide is a very common and important odorant with wastewaters
H2S is extremely odorous: 1 ppm H2S equals 1,000 ouE/m3
H2S can severely damage concrete:2 y g
If H S i t d ill b t If H2S is present, odour will occur, but: If no H2S is present, other odorants may still be relevant!
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6 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Odour measurement in the liquid: The OEC
The Odour Emission Capacity OEC of a liquid is the total amount of odorants present in that liquid that can be stripped from this liquid under standardized
conditions. [Frechen and Köster, Wat.Sci.Tech.,1998]
It is given in European odour units per cubic meter of liquid Its unit is ou /m3liquid. Its unit is ouE/m3
liquid
The OEC method is covered by the new VDI guideline 3885/1 ItThe OEC method is covered by the new VDI guideline 3885/1. It will be published 2012/2013
A t i ff th d t i t i tifi ti b d bAs we strip off the odorants into air, quantification can be done by the standard olfactometric method according to CEN 13725:2003
Also, different analytical procedures can be applied to the stripped air, resulting in Emission Capacities of the substances analysed
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7 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011OEC test reactor
Off gas outlet / sampling portOff gas outlet & sampling point
m
Liquid sample
0.10
0.354 m
pH‐measurement
sample30 Liter
5 m
Flowmeasurement
aerator 0.34
5
P t l Franke
odourless air Pressure control
Odourless air © Frechen
, odourless air
0.315 m
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8 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011OEC Evaluation
2.000Lu
ftr
1 500
olfaktometrische Meßwerte
GE E
/m3 L
OEC = (c d‐c100)/V dVLu E/m
3 ai olfactometric measurement results
1.500
berechneton in
G OEC = (cod c100)/Vp dVLwith Vp = 30 L
c odin o
test duration
1.000 extrapoliert
Test-Dauerzent
rati
tration
test duration
extrapolated
500
offk
onz
concent
0100chss
tood
our c
00 200 400 600
Luftmenge in Liter
Ger
uo
air volume in Liter
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9 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
Luftmenge in Literair volume in Liter
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011H2S cannot replace odour as a parameter
Municipal sewer Meat industry
OdourOEC: 5,210,000 ouE/m3
liquid
OdourOEC: 594,000 ouE/m3
liquid
H2S
H2S
Dimethylsulphide
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10 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Application
1 Characterizing different liquids concerning their odour1. Characterizing different liquids concerning their odour relevance (results so far):
Sewage: 80,000 (5,000 – 400,000) ouE/m3liquid
Excess sludge fresh: 30,000 (9,000 – 150,000) ouE/m3liquid
Filtrate stabilized sludge: 110,000 (5,000 – 400,000) ouE/m3liquidq
Filtrate raw sludge: 2,000,000 (up to 10,000,000) ouE/m3liquid
Sewage exceeding 50,000 ouE/m3liquid is generally accepted as critical
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11 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Example pressure mains
400.000
450.000
y = 90117x + 2419,9R² = 0,9805
300 000
350.000sigkeit
quid
250.000
300.000
E/m
3 Flüss
u E/m
3 liq
150.000
200.000
P in GE E
C in
ou
50 000
100.000GEP
OEC
0
50.000
0 1 2 3 4 50 1 2 3 4 5Aufenthaltszeit Druckrohrleitung in hhydraulic residence time in the pressure main in h
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12 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Application
1 Characterizing different liquids concerning their odour1. Characterizing different liquids concerning their odour relevance
2 Characterizing industrial discharges set standard and control2. Characterizing industrial discharges, set standard and control whether standards are met:
Brewery: up to 3,000,000 ouE/m3liquid
Chemical industry: up to 12,000,000 ouE/m3liquid
Paper industry: up to 6,000,000 ouE/m3liquid
Tannery: up to 15,000,000 ouE/m3liquid
Meat industry: up to 10,000,000 ouE/m3liquid
Yeast industry: up to 40,000,000 ouE/m3liquid
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13 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Application
1 Characterizing different liquids concerning their odour1. Characterizing different liquids concerning their odourrelevance
2 Characterizing industrial discharges set standard and control2. Characterizing industrial discharges, set standard and control whether standards are met
3 Identification of problems e ample paint shop rec cle ater at3. Identification of problems: example paint shop recycle water at a big car factory (1,800 cars per day)
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14 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Application
1 Characterizing different liquids concerning their odour1. Characterizing different liquids concerning their odourrelevance
2 Characterizing industrial discharges set standard and control2. Characterizing industrial discharges, set standard and control whether standards are met
3 Identification of problems e ample paint shop rec cle ater at3. Identification of problems: example paint shop recycle water at a big car factory (1,800 cars per day)
4 P f f ffi i f d i h i l i t th t4. Proof of efficiency of dosing chemicals into the sewer system for odour suppression/reduction
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15 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Application
1 Characterizing different liquids concerning their odour1. Characterizing different liquids concerning their odourrelevance
2 Characterizing industrial discharges set standard and control2. Characterizing industrial discharges, set standard and control whether standards are met
3 Identification of problems e ample paint shop rec cle ater at3. Identification of problems: example paint shop recycle water at a big car factory (1,800 cars per day)
4 P f f ffi i f d i h i l i t th t4. Proof of efficiency of dosing chemicals into the sewer system for odour suppression/reduction
5 E ti ti f d l t d5. Estimation of odour release at drops
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16 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Application
1 Characterizing different liquids concerning their odour1. Characterizing different liquids concerning their odourrelevance
2 Characterizing industrial discharges set standard and control2. Characterizing industrial discharges, set standard and control whether standards are met
3 Identification of problems e ample paint shop rec cle ater at3. Identification of problems: example paint shop recycle water at a big car factory (1,800 cars per day)
4 P f f ffi i f d i h i l i t th t4. Proof of efficiency of dosing chemicals into the sewer system for odour suppression/reduction
5 E ti ti f d l t d5. Estimation of odour release at drops6. Forecast the impact of system changes on the odour emissions
fof a system
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17 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011
E l H b di h f
Forecast of system changes
Example Hamburg: discharge ofa yeast industry wastewater via5 k i i t d fa 5 km pressure main instead of
discharge into a gravity sewer( t l it ti ) h f(actual situation): change ofquality concerning odour?
Test in DESEE’s research pressuremain: OEC measurement of the
© DESEE
“fresh” wastewaterand of the waste‐water after varyinghydraulic residencetimes in thepressure main © DESEE © DESEE
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18 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Application
1 Characterizing different liquids concerning their odour1. Characterizing different liquids concerning their odourrelevance
2 Characterizing industrial discharges set standard and control2. Characterizing industrial discharges, set standard and control whether standards are met
3 Identification of problems e ample paint shop rec cle ater at3. Identification of problems: example paint shop recycle water at a big car factory (1,800 cars per day)
4 P f f ffi i f d i h i l i t th t4. Proof of efficiency of dosing chemicals into the sewer system for odour suppression/reduction
5 E ti ti f d l t d5. Estimation of odour release at drops6. Forecast the impact of system changes on the odour emissions
fof a system7. Online Sulphide and OEC measurement Unit (SOU)for process
l f h l d hcontrol purposes of chemical dosing into the new sewer emscher:kanal utilizing H2Sg sensors and electronic noses
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19 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Overview emscher:kanal
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20 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Overview emscher:kanal
Gravity flow sewer „emscher:kanal“ (cost > 2 billion €, ready 2016) 51 km long, depth up to 40 m 113 manholes (every 300 – 600 m), Diameter 12 m 1 or 2 pipes, max. 2,800 mm wide Technical ventilation: design DMTg
Deutsche Montan TechnologieGmbH – Bergbau Service‐Wettertechnikg
38 waste air treatment facilities: design 38 waste air treatment facilities: designUniversity of Kassel, Department ofSanitary and EnvironmentalSanitary and EnvironmentalEngineering (DESEE)
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21 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011basic considerations for chemical dosing
A di t t i l i ti t’ ti d t t According to a material scientist’s expertise, due to concrete corrosion prevention, a maximum of 1 ppm H2Sg in the air inside th t t b d dthe sewer must not be exceeded
Additional measures concerning the wastewater, i.e. dosing of h l blchemicals, are inevitable
Depending upon circumstances, possible strategies are an oxygen carrier (such as calciumnitrate) can be used to prevent
anaerobic conditions and subsequent sulphide formation or t l lt b d f i it ti f h d l hidmetal salt can be used for precipitation of hydrogen sulphideNon‐sulphur odorants can be oxidized e.g. with H2O2
In order to minimize consumption of chemicals a closed loop In order to minimize consumption of chemicals, a closed‐loop process control is under research at DESEE incorporating SOUtechnology that is able to prevent overdosing and unnecessarytechnology that is able to prevent overdosing and unnecessary costs
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22 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Dosing of chemicals for odour emission suppression
Load (sulphide, OEC) Dosing amount
100 % safe“ but much too expensive
OE
C)
„100 % safe , but much too expensive
cheaper“ but still
hide
, O
„cheaper , but still overdosing, some-
times overload
(sul
ph
Closed loop processcontrol assuring optimal
Load
control assuring optimal dosing regarding cost and
efficiency
time
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23 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Dosing of chemicals for odour emission suppression
mg/
L]at
ion
[mfo
rma
lphi
de
sul
time [h]
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24 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Online Sulphide + OEC measurement Unit (SOU)
1st t t SOU ( t K l t )Reactor for OECmeasurement
1st test SOU (at Kassel wwtp)
Reactor for H2S‐ /sulphidemeasurement
Colour display/data storage &
PCS
measurement data storage &processing
Measurement of sulphideby lowering pH down to 4and air stripping /H2Spp g /measurement
OEC by stripping andAir supply
OEC by stripping andusing eNose
measurement interval10 mins
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25 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Dosing process control (schematic example)
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26 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.20112nd + 3rd SOU in operation at the Bottrop Sewer
© Frechen
Purpose: avoid overdosing avoid underdosing avoid underdosing
© Frechen
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27 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
© Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.20112nd + 3rd SOU in operation at the Bottrop Sewer
© Frechen© DESEE
Purpose:
© DESEE
avoid overdosing avoid underdosing avoid underdosing
© DESEE
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28 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
© DESEE
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Simple dosing schme
H2S FeCl2YH2Sexistent
FeCl2dosing
Y
N
OEC H2O2Y> 50.0002 2
dosingY
N
okay
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29 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Sensors needed for an online measuring SOU
f th l hid t f th SOU f H S i for the sulphide part of the SOU, a sensor for H2Sg is necessary (readily available on the market)
for the OEC part of the SOU, a sensor is needed that might be able to indicate the odour (thus replacing the test person panel): an “electronic nose”
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30 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011eNoses under research (excerpts)
© Frechen
© Frechen
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31 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
© Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Principles of eNoses
S i d t t h d t d t l ti Semiconductor: current changes due to odorants accumulating in the detector sensitive layer
Oscillating Quartz: frequency changes due to mass of odorants accumulating in the detector sensitive layer
Usually 4 to 10 different sensor signals: different sensors (sensor materials) or different measurement conditions (heating profiles, ) ( g p ,dilution)
100%S1 (aromatic)
S10 (methane
AK Bottrop
20%
40%
60%
80% S2 (broadr.)
S3 (aromatic)S9 (sulphur, chlor)
S10 (methane-aliph)
Schwarzbach
Dr ckrohrleit ng0%
0%
S4 (hydrogen)S8 (broad, alcohol)
Druckrohrleitung
Biogasanlage: Mais-Silo (feucht)
S5 (arom-aliph)
S6 (broad, methane)
S7 (sulphur, organic) Bauernhof: Gülletank
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32 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
Legende: S1…S10 sind die Sensoren des Multisensormessgerätes
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Can eNoses measure the olfactometric odour conc.?
Th f t N ld b bl t th REAL d The perfect eNose would be able to measure the REAL odourconcentration. This means that a mathematical model exists that
t 4 t 10 di i t b (th REALconverts 4 to 10 sensors readings into one number (the REAL odour concentration)
To establish such a model, it is necessary to do parallel measurements with eNose olfactometer
The more parallel readings (the bigger the mathematical sample size), the better the mathematical model can be
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33 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011DESEE’s data pool (09/2010)
DESEE’ d t l DESEE’ datapool: 5 eNose brands 3 olfactometry labs 3 olfactometry labs Different origins of odours
project eNose period olfactomery origin of odour numberproject eNose period olfactomery origin of odour numberVienna A 2005 Lab 1 wastewater 382Vienna B 2005 Lab 1 wastewater 156Hilter A 4/2008 ‐ 5/2008 Lab 2 wastewater 40emscher sewer A 1/2007 ‐ 1/2008 Lab 2 wastewater 150Biofilter C 2009 Lab 2 wastewater 12Biofilter C 2009 Lab 2 wastewater 12OEC with wastewater A,A 2010 Lab 2 wastewater 88safety research part 1 A,A 2007 drugs/explosives (8)f h d / l ( )safety research part 2 A,A 2010 drugs/explosives (40)
lab test C 2009 hydrogen sulphide (20)Verden A,A 2010/2011 Lab 3 wastewater 44Aachen A,A 2011 Lab 3 wastewater 156Berlin A,B,D,E 2011 Lab 3 wastewater 366
total with olfactometry: 1 394
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34 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
total with olfactometry: 1.394
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Possible sources of problems and errors
S li Sampling Uncertainty of olfactometric measurement The eNose itself The odour’s nature The odour s nature
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35 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Possible sources of problems and errors
S li Sampling type of eNose (batch‐like measurement or continuous reading) sampling location different constituents of odours sampling location – different constituents of odours Unsynchronized clocks of sampling devices involved (this might be
overcome by doing the eNose measurement from the same sample bag asovercome by doing the eNose measurement from the same sample bag as the olfactometric measurement)
Sample bags storage time
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36 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Possible sources of problems and errors
U t i t f lf t t i t Uncertainty of olfactometric measurement It has to be differentiated between THE REAL ODOUR and THE ODOUR
MEASURED BY OLFACTOMETRYMEASURED BY OLFACTOMETRY Olfactometry measurement has an error itself. According to Boeker (2005)
this can be estimated to be 50%. This means: if an eNose perfectly explains the odour as measured by
olfactometry, (claimed by some vendors of eNoses: R2 = 1 !!), the model has an error of 50%!
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37 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Possible sources of problems and errors
Th N it lf The eNose itself t90‐time
no information provided by the manufacturers no information provided by the manufacturers t90‐time differs from sensor to sensor t90‐time differs from odour to odour90
Some sensor signals do not converge to a final value at all – then there is not90‐time at all …
70.000
80.000
90.000
11 500
12.000
12.500
40.000
50.000
60.000
nsor re
ading
10.500
11.000
11.500
nsor re
ading
10.000
20.000
30.000sen
9.500
10.000
sen
0
1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031323334353637383940414243
time [s]
9.000
1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031323334353637383940414243
time [s]
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38 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Possible sources of problems and errors
Th N it lf The eNose itself t90‐time oscillating readings mean used oscillating readings – mean used
10.420
10.380
10.400
10.340
10.360
reading
10 300
10.320
sensor
10.280
10.300
10.260
1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70 73 76 79 82 85 88 91 94 97 100
103
106
109
time [s]
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39 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Possible sources of problems and errors
Th N it lf The eNose itself t90‐time oscillating readings mean used oscillating readings – mean used do 2 eNoses of the same type and age deliver the same readings?
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40 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Possible sources of problems and errors
Th N it lf The eNose itself t90‐time oscillating readings mean used oscillating readings – mean used do 2 eNoses of the same type and age deliver the same readings? aging of sensors aging of sensors
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41 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen
4th IWA OVE Conference Vitoria/Brazil, 18.10.2011Finale ....
Th k f ki d i !Thanks for your kind attention!
this (and more) presentation(s) can be downloaded fromwww uni kassel de\fb14\siwawiwww.uni‐kassel.de\fb14\siwawi
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42 Department of Sanitary and Environmental Engineering (DESEE) Head: Prof. Dr.‐Ing. F.‐B. Frechen