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Odour Management101

Presented by:

Anna H. Bokowa, M.Sc.ORTECH Environmental

Mississauga, OntarioCANADA

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OVERVIEW

• Odour Sampling Issues• How the Odour is Measured• Point Sources• Importance of Dilution Technique• Area Sources -which Method to Use?• Fugitive Sources• Ambient Sampling• Introduction to results using different Techniques• Conclusions

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• Methods are not standardized except for odour evaluation standard in Europe, Australia

• EN:13725:2003 “ Air Quality –Determination of Odour Concentration by Dynamic Olfactometry” is design more for evaluation of the already collected samples, not sampling

• Australia and New Zealand Standard – similar to European• Draft Ontario Ministry of Environment Method-Source Sampling for Odours, version 2, 1989

• No specific method for odour sampling in US except ambient measurement and

• A&WMA EE-6 Odor Committee – sub-committee called for development of draft odour sampling standard

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Odour Sampling Issues

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• Different odour sampling methods are used in different countries

• However most of countries agree with dilution technique especially when sampling at hot or humid sources

• Only in US it is a common practice to collect undiluted samples from these sources

• How important is dilution technique at these sources?

Odour Sampling Issues-con’t

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• How good are the analysis if the samples are not collected correctly?

• How anyone can Install a very expensive odour control equipment without a proper assessment of the facility

• Is it true well rounded annual condition established at facility when only one or two samples collected

• The accuracy of the results is limited when the number of samples is limited

Odour Sampling Issues (cont’d.)

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• Trend for municipal requests for proposal to specify analysis according to the European standard EN13725; 2003, but only one sample per source is defined just to reduce cost

• Most of the bids in Ontario are based on the lowest cost not quality of work

• Needs for proper odour assessment

• Needs for proer sampling methodology used in assessment

Odour Sampling Issues (cont’d.)

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• Proper sampling procedures especially for point sources when high in temperature and moisture content

• Proper sampling for area sources

• Number of samples per source

• Proper sampling for ambient locations

Odour Sampling Issues (cont’d.)

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• How good are the analysis if the samples are not collected correctly?

• Installation of very expensive odour control equipment without a proper assessment of the facility?

• Trend for municipal requests for proposal to specify analysis according to the European standard EN13725; 2003, but only one sample per source is defined

• The accuracy of the results is limited when the number of samples is limited

Odour Sampling Issues (cont’d.)

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• Different approaches for different sources

• Types of Sources: Point Sources- for example stacks, vents Area Sources-open piles, open tanks Fugitive Sources-windows, open doors, trucks

How the Odour Is Measured?

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• dilution technique• lung technique• flux chamber technique• wind tunnel technique

Sample Collection Procedures

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• Tedlar bags used for collection of samples• Other materials approved by European

standard • Residual odour from Tedlar, therefore a new

bag must be cleaned before use• Purging of the bags before collection• Importance of the volume of the sample• Sampling time• Number of samples per source• Performance (inlet/outlet) tests

Collection of the Samples

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• Importance of collecting more than one sample per source

• One sample per source- very common practice when issuing a request for proposal, even from municipalities when assessing odours at WWTP, rendering plants,

• Importance of testing under different process conditions

Number of Samples per Source

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• Odour sample diluted with nitrogen during sampling to prevent condensation, absorption and oxidation

• diluted sample collected at the temperature of the source

• pre-dilution test to calculate the optimum dilution level

• triplicate samples at each of four dilution levels (MOE requirement)

HeatedSampler

Probe

Nitrogen

Stack

TedlarGasBag

Dilution Sampling Technique

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Dynamic Pre-dilution Sampling

• odor samples collected using dilution sampling apparatus

• emission gases are diluted with nitrogen as the gases are extracted from the emission source

• nitrogen as a dilutant gas not air

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Predilution Ratio Determination

• collection of three samples at four different dilutions and calculation of the optimum dilution ( the highest ODTV)- MOE requirement

• analysis of the remaining two samples at the optimum dilution

• the geometric mean of the three samples at the optimum dilution is used for the emission rate calculation

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Is it time for Change in Procedure?

• Different times for different dilutions

• Possibly changes in process with time

• Ideally collect samples at different dilutions at the same time ( preferably two of three dilutions)

• Requires installation of minimum of 2 samplers at the same time at one source/stack

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Sampling at Point Sources

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Why Dilution is so Important?

To Prevent:

• condensation• adsorption of odours• chemical reactions such as oxidation

upon sample collection and cooling to ambient temperature

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Odor Sampler

• Based on the eductor• heated to the source temperature• range: 60 times to 8 times or

250 times to 60 times• calibrated with propane gas at different

temperature settings

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Lung Odour Sampler

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used for cold, low moisture sources, low in odour sources, ambient samples

Probe Pump

Stack

TedlarGasBag

Lung Technique

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Ambient Sampling using Lung Technique

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Results-Diluted Samples vs Undiluted

SamplingLocation

SampleNo. Predilution

Raw ODTV

(ou)

NetODTV

(ou)

Geometric MeanNet ODTV

(ou)

Source 1 1 50 651 32,550

2 50 668 33,400 34,294

3 50 742 37,100

1 40 636 25,440

1 60 336 20,160

1 1 2130 2,130

2 1 1969 1,969 2,075*

3 1 2130 2,130

*16X lower value

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Results-Diluted Samples vs Undiluted

SamplingLocation

SampleNo. Predilution

Raw ODTV

(ou)

NetODTV

(ou)

Geometric MeanNet ODTV

(ou)

Source 2 1 40 19 760

1 30 50 1,500

2 30 56 1,680 1,588

3 30 53 1,590

1 20 57 1,140

1 1 123 123

2 1 121 121 124*

3 1 128 128

*13X lower value

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Tedlargas bag

flux chamber

pump

flowmeter

sampling lungnitrogen cylinderbiofilterbiofilter

used for sampling at open sources (e.g., lagoons, storage piles)

Flux Chamber Technique

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Flux Chamber Sampler

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Area Source Sampling

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used for sampling of area sources

Wind Tunnel Technique

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ODTV-Thickener Vessel-Wind Tunnel MethodDate Sampled Sample Predilution Raw Odour Detection Net Odour Detection Geometric Mean

No. Ratio Threshold Value Threshold Value ODTVODTV ODTV

ou ou ou

August 3, 2006 Sample #1 1 724 724

Sample #2 1 845 845

Location 1 Sample #3 1 819 819

756

Location 2 Sample #1 1 724 724

Sample #2 1 709 709

Sample #3 1 724 724

Odour Emissio Rate = 61.99 ou/s/m 2

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ODTV-Thickener Vessel-Flux Chamber MethodDate Sampled Sample Predilution Raw Odour Detection Net Odour Detection Geometric Mean

No. Ratio Threshold Value Threshold Value ODTVODTV ODTV

ou ou ou

August 3, 2006 Sample 20X#1 20 985 19700

Sample 20X#2 20 826 16520

Location 1 Sample 20X#3 20 738 14760

19864

Location 2 Sample 20X#1 20 1158 23160

Sample 20X#2 20 1192 23840

Sample 20X#3 20 1158 23160

Odour Emission Rate = 5.19 ou/s/m 2

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Geometric EmissionMethod Pre-Dilution Mean of Rate Difference

OTV Samples ou/s/m2(ou)

Wind Tunnel None 760 6211 X

Flux Chamber 20 19,860 5.1

Wind Tunnel vs Flux Chamber Sampling

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• European- 13725 ; 2003 “Air Quality- Determination of Odour Concentration by Dynamic Olfactometry”

• Australian/New Zealand-AS/NZS 4323.3:2001-”Determination of Odour Concentration by Dynamic Olfactometry”

• ASTM 679-2004; “Standard Practice for Determination of Odor and Taste Threshold by Forced-Choice Ascending Concentration Series Method of Limits”; needs to be updated

• ASTM E544-2001; “Standard Practices for Referencing Superthreshold Odor Intensity”; needs to be withdrawn or replaced due to high exposure of n-butanol concentrations used for comparision ( 10 ppm to 20,000 ppm n-butanol in water)

• Draft AWMA EE-6-”Guideliness for Odor Sampling and Measurement by Dynamic Dilution Olfactometry”; needs to be updated

Standards for Odour Evaluation

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• emission rate (ou/s) - m3 basisOdour detection threshold value (ou)

x volumetric flowrate (m3/s)

• dispersion modelling

predicted concentration (ou) at receptors• exceedance of the 1 ou guideline may result in

the requirement for an odour emission reduction program

Odour Calculations

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• Lung sampling followed by dynamic olfactometry evaluation

• Portable Olfactometer – Scentometer or Nasal Ranger for Ambient Odour Investigation

Ambient Odour Sampling

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• upwind and downwind locations• a few locations chosen with the distance from

the facility• minimum three samples per location • sampling time depends on duration of

detectable odour• lung technique used for collection samples

Ambient Odour Sampling (Lung)

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Scentometer

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Nasal Ranger

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Portable Olfactometer

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Ambient Levels Based on AmbientSampling and Nasal Ranger Reading

Description

Ambient Level Based onAmbient Sampling

(ou)

Nasal RangerReadings

(DT)

Location 1 29 15

Location 2 12 7

Location 3 12 4

Location 4 8 <2

Location 5 9 2

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Conclusions

Loss of odour up to sixteen times by:• not using proper sampling • not diluting a sample at the source with

nitrogen • not heating a sampler to the source

temperature• not determining an optimum dilution• not preventing samples from direct sunlight

contact

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• Importance of the proper testing and analysis otherwise the loss of odour might be a significant and predicted off-site odours will be lower then the real ambient levels

• All sources should be assess not only point sources

• Caution should be used when some of the devices are used for ambient levels determinations

Conclusion-con’t

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Contact Information

Anna H. Bokowa, M.Sc.

Manager, Odour Assessment

ORTECH Environmental

1-877-774-6560, Ext. 669

abokowa@ortech.ca