Special odour sampling procedure with nitrogen dilution has been developed by Uniqair and Purdue University Odor Lab for odour samples with high humidity from dryers and coolers. The nitrogen will preserve the odor and prevent condensation for more accurate odor concentration test results.
Unlike VOC testing, the odour lab is utilizing human noses of screened panel members with odor sensing capabilities that reflect the average person according the latest ASTM and CEN odor testing standards. Odour samples are diluted until detection threshold; the required number of dilution is the odour concentration: DT (Detection Threshold) or ou/m3 (Odour Units per cubic meter). Some food or feed processes with high fat and protein content can have high odour concentrations in the (untreated) air from the dryers of 100,000 DT or ou/m3. This means it needs a stack dilution of 100,000 to ground level. But for example fish feed generally has even more odour, so for fish feed a Plasma-Injector with more energy capacity is applied to oxidize these odours. Most countries/states now recognize the latest European CEN-13725 odour standards and cold plasma odour oxidation for feed and food dryer stack odour control.
Uniqair Technologies Ltd (BC-Canada)
We are the originators of advanced high frequency cold plasma injection odour control systems for stack emissions.
Unlike incinerators, chemical- or water scrubbers or bio-systems, the PLASMA-INJECTORTM is an oxidizer that does not need any chemicals or water and does not generate any waste.
Our experience includes over 100 systems for stack odour control: dryers of Petfood, fish feed, etc.
Plasma-Injector: a compact cold plasma-injection technology, selected as Best Available Technology in Europe, Asia and N-America. The Plasma-Injector is oxidizing odours instantly with oxygen radical injection from ambient air; for example 12,000 cfm (20,000 m3/h) with only 6 to 9kW energy consumption. Simple on/off control. See www.uniqair.com or email@example.com for more info.
Purdue University (IN - USA)
The Purdue Agricultural Air Quality Laboratory (PAAQL) is part of the Department of Agricultural and Biological Engineering at Purdue University, West Lafayette, Indiana, USA. The PAAQL specializes in odor assessment using field and laboratory olfactometry, chemical analyses using gas chromatography-mass spectrometry with olfactory sensing (GC-MS-O), ion chromatography, closed-cell FTIR spectrometry, and continuous emissions monitoring of ammonia, hydrogen sulfide, carbon dioxide, methane, nitrous oxide, ethanol, methanol and particulate matter. PAAQL personnel have been studying the science and engineering of odor, gas, and dust emissions since January of 1994. Our research has served industry, government and agribusiness, in addition to communities at large.
More info at https://engineering.purdue.edu/~odor/