OLFASCAN nv offers a variety of services concerning odour-issues in industrial and agricultural activities. All projects are lead by certified experts (certified by the Flemish government)
There are thousands of organic compounds who can contribute to the perceived odour. Some of these odorous compounds can be present in very low concentrations which can not be measured using conventional analytical methods. For these particular cases, OLFASCAN offers GC-Sniffing. This analytical method combines highly sensitive analytical techniques with the human nose as odour detector. The very high sensitivity of the human nose for odours, makes it possible to detect compounds with a very low odour threshold value. This type of analysis reveals highly valuable sensorial information of the analysed air sample.
Advice on sanitation
OLFASCAN nv gides the client in chosing the appropriate emissionreducing and sanitational measures. Both procesintegrated and end-of-pipe technologies may be applied.
Chemical air analyses
OLFASCAN nv is equipped with a state-of-the-art device to perform chemical analyses. This way, volatile organic (odorous) compounds can be determined qualitatively and/or quantitatively using a sensitive gas chromatograph with mass spectrometry, equipped with a thermal desorption unit. This set-up allows OLFASCAN nv to achieve limits of detection of only a few ppbv.
Consulting on ventilation
When performing smoke tests, the air circulation pattern can be visualized. A cloud of smoke is released on several locations in the area to be evaluated. The cloud is generated by a smoke generator. This way the efficiency of the ventilation system can be evaluated, blind spots can be traced or areas which possibly need adaptations due to e.g. temperature stratification, can be marked. Also leaks or diffuse emissions can be detected. The performance of local air extraction is typically investiged using smoke tester tubes.
Dispersion modelling using ISC (US-EPA)
To determine the impact of a company on its surroundings, dispersion modelling can be used. An estimation is made of the contribution on immission level. Characteristics of the source, like height, flow,… the emission values are entered in a long term, bi-Gaussian dispersion model. Considering the meteorological data of a representative year, it is possible to calculate the frequency of exceedences of a certain immission concentration at several locations around the source. The plotted contours show the regions around the source where the concentration is exceeded and allow to check with imposed standards.
Determination of emissions form certain products/materials
By simulating process parameters in the lab, products/materials can be individually screened for odorous compounds. Both GC-MS as GC-Sniffing analyses can be applied to identify the compounds responsible for the (unwanted) odour. The information obtained makes it possible to take well-considered measures.
Olfactometric emission research
The odour concentration of a gas can be measured objectively by olfactometry. The emitted volatiles/odorants are collected in special sampling bags and analysed at the laboratory. To determine the odour concentration, expressed in European odour units ouE/m³, an olfactometer is used according to the European standard (EN13725).
Field panel measurements
The goal of a field panel measurement is to determine the impact of odour of the company on its immediate surroundings. The study is based on mapping the areas where odour can be perceived. These sensoric measurements are conducted by trained, calibrated and objective observers of OLFASCAN. During the measuring campaign an amount of unannounced field panel measurements are performed at different times, with different meteorologic conditions. Field panel measurements are performed according to the Flemish Code of Good Practice.
Using modelling, for every measurement an average odour emission is calculated. Based on the results of a measuring campaign (10 field panel measurements) the odour impact is determined using an odour model. In this model the odour concentration as well as the frequenvy of perception is calculated. Results are presented on a topographic map by means of plotting predetermined odour contours.
Air change rate measurements – diffusive emission
The ventilation flow rate of a space can be determined by the air change rate measurement method. A certain amount of a tracer gas will be dosed into the tested space until a certain concentration is obtained. From this point the gas supply in the space is aborted, immediately followed by the logging of the gas concentrations for a certain amount of time using a photo acoustic detector. When the tracer gas supply is stopped, a logarithmic decreasing gas concentration will be measured due to natural and/or mechanical ventilation. From the corresponding rate of concentration decrease, the air change rate can be calculated.
Based on these air change rate measurements, combined with simultaneous odour concentration measurements, an estimation of the diffusive odour emission from the space can be made.
Follow-up and evaluation of odour reducing measures
A malfunctioning biofilter or scrubber typically emits too high residual concentrations leading to odour nuisance and complaints.
OLFASCAN provides the opportunity to follow-up the efficiency of your biofilter or scrubber, so that (preventive) actions can be taken when needed. This way an optimal odour reducing efficiency can be maintained.
Environmental impact assessment
Amongst the staff their are 2 recognised experts in 'air' as well as 2 experts in 'fauna and flora'.
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