WEF Odors and Air Pollutants 2012 Louisville. Odors conference? Is it not H2S conference?

WEF odour and pollutants in the air 2012   As I wait here at the airport, after an intense 3-day conference organized by the WEF I ask myself if it was the money of the olores.org advertisers worth, once the event has ended.

   Alright, I have met again all the colleagues and that is nice. I met Mike McGinley from St Croix and Thierry Pagé from Odotech. I spoke with the people of Ecometrika Chile and I met a lot of interesting people selling a bunch of different solutions like scrubbers, biofilters, ozoners, bioscrubbers, etc to manage“odors”…

   .. to manage odors? Is that right? Do they really treat odors? The answer comes plain from my point of view: No, none of the equipment shown at the event was specifically designed to treat odors, but to treat H2S, which is not quite the same.

   Measuring H2S instead of “odor” is like measuring vibration instead of noise, or measuring “sales” instead of “profit”. There is a very nice correlation between both parameters in many cases, but this correlation might get a bit uglier at lower H2S concentrations (1) (2).

   Every single equipment was designed to treat H2S. None of the makers in the various booths at this conference has shown any data of efficiency in terms of odor units when asked about it. This is not a surprise if taken into account that there are just 3-4 olfactometric labs in USA*. If every operator rely on H2S measurement instead of a proper olfactometric measurement, no wonder there is no business for more olfactometry labs in the States!!

   During 2010 and 2011, the LUFA Nord-West Institute (Germany) in collaboration with the DLG has carried out the evaluation of the official measurements of 96 units of treatment equipment (3). Of these 96 measurements, 56 corresponded to initial audits and 40 were verifications following a period of time in operation. The key criteria for the odor evaluation performance were two:

  • No detection of odor from the inlet in the outlet
  • Odor emission limit value of 300 ouE/m3

Here there are just a few examples.

Report Type of Equipment Maker/Distributor Date of test
6057 Odour abatement equipment in two steps Siemers Umwelttechnik Jan-12
6051 Odour Abatement plant „Abluftwäscher Rohreinbau“ Reventa Dec-11
6050 Odour Abatement plant HelixX Big Dutchman  Dec-11
5957 Odour Abatement plant HelixX Big Dutchman Aug-10
5955 3-steps Odour Abatement equipment BIO Flex 3-step SKOV Aug-10
5954 2-steps Odour Abatement equipment BIO Flex 2-step SKOV Aug-10
5952 Odour Abatement Plant MagixX-B Big Dutchman Aug-10
5944 2-steps Odour Abatement Plant Siemers Umwelttechnik Jun-10
5880 Odour Abatement equipment. Chemical Scrubber Uniqfill Air Jul-09
5879 Odour Abatement equipment “Combined biologic Scrubber BCA 70/90" Devriecom Jul-09
5702 Odour Abatement Equipment "Dorset-Biotrickling" Dorset Green Machines bv Sep-07
5699 Odour Abatement Equipment for pig farms Hagola Biofilter Sep-07
5451 Floating Cover to reduce odour emission Hexa-Cover ApS Sep-07

   This is the difference and from my point of view, a very significant one.

   There is a need for data from the makers of  odor abatement equipments in the form of odor efficiency and not H2S.

   Another interesting observation is that there is generally a trend towards the  comparison of odor measured in a lab by means of dynamic olfactometry and odors measured with a field olfactometer such as the Nasal Ranger or the newer Scentroid SM100.

   Dilution to threshold D/T is not an standardized “odor unit”. A D/T measurement has no correlation with a measurement made with a dynamic olfactometer (4)(5) according to the EN 13725.

   From my point of view, there is little use for a measurement of D/T in terms of proof of compliance for odour abatement equipments. Nor of H2S measurement. Most of the operators that presented papers in this Odors and Air Pollutants 2012 organized by the Water Environment Federation (WEF) preferred to spend hundreds of thousands of dollars in expensive equipment for odor abatement but save a few thousands in the evaluation of these equipments with a repeatable and reproducible and thus standardized method named dynamic olfactometry. The fascinating presentation of Charles McGinley(6) in this 2012 conference was quite refreshing and also clear about precision and accuracy of odor control system performance tests.

   The organization of the Odors and Air Pollutants 2012 Conference in Louisville was excellent and I would like to congratulate the organizers. This year and according to the list of participants, I was the only European there. This situation was a bit unusual as there was plenty of talks about the “European” norm.

   I would like to encourage to scientists and operators to come over to the next 2014 WEF conference. This year there were plenty of interesting talks and a very valuable contribution of scientists, technicians and plant operators. However if you did no come this time to Louisville, you have definitely lost the chance of enjoying a soothing glass of Kentucky bourbon.


* Just in a small country as Spain there are 6 olfactometric labs, 4 of them with the ISO 17025 and EN 13725 accreditation. In Germany, there are over 15 labs.


(1) Gostelow, P., SA Parsons (2000). “Sewage treatment works odour measurements.” Wat. Sci.Technol. 41(6), 33-40.
(2) Gostelow, P., SA Parsons, RM Stuetz (2001). “Odour Measurements for Sewage Treatment Works.” Water Research 35(3): 579-597.
(3) Broer L. (2011): Geruchsminderung durch Abluftreinigung bei Tierhaltungsanlagen– Wie zuverlässig sind zertifizierte Anlagen in der Praxis. In: VDI Wissensforum GmbH (Hrsg.): Gerüche in der Umwelt. VDI-Berichte 2141.
(4) Sheffield R., Thompson M., Dye B., Parker D. Evaluation of Field-based Odor Assessment Methods. WEF/A&WMA Odors and Air Emissions 2004
(5) Bokowa A.,Ambient Odour Assessments: Comparison of Two Techniques Used for Assessing Ambient Odours.3rd IWA Odour Conference, October 2008.
(6) McGinley C.Precision & Accuracy of Odor Control System Performance Tests. WEF Odors and Air Pollutants 2012.



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Carlos Nietzsche Diaz Jimenez's Avatar

Carlos Nietzsche Diaz Jimenez

Carlos is the editor-chief of olores.org and has been in the odour world since 2001. Since then, Carlos has attended over 90 conferences in odour management, both national and international and authored a few papers on the subject. He has also organized a few international meetings and courses. Carlos owns a small company named Ambiente et Odora (AEO). He spends his free time with his wife and his twins, Laura and Daniel, and of course, writing on olores.org.