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Andersen K.B.,Applied Plasma Physics AS | Andersen K.B.,University of Aarhus | Hansen M.J.,University of Aarhus | Feilberg A.,University of Aarhus
Journal of Chromatography A | Year: 2012

Methanethiol (MT) is a potent odorant that can be difficult to measure due to its high volatility and reactivity; it easily reacts to form dimethyl disulphide (DMDS) during sampling and/or analysis. This paper focuses on finding an optimal method for sampling and measuring MT with minimum artefact formation using sorbent materials and a thermal desorption-gas chromatography-mass spectrometry method (TD-GC-MS). Experiments were conducted to identify suitable sorbent materials and tubes for analysis. Breakthrough, desorption rate, the effects of storage and desorption temperatures were investigated and different drying methods were established with respect to quantitative sampling and formation of DMDS. Proton-transfer-reaction mass spectrometry (PTR-MS) was used in the development of the method and was an especially useful tool for determination of breakthrough. The results show that glass tubes packed with silica gel for pre-concentration of MT before analysis with TD-GC-MS give the best results. In addition, a combination of Tenax TA and carbonised molecular sieve or Tenax TA cooled to ≤0°C gives acceptable results. 80°C was found to be the optimal desorption temperature. For all the sampling methods tested, storage conditions were observed to be very critical for transformation of MT. Room temperature storage should be limited to few minutes and, in general, tubes should be kept at 0°C or lower during storage. © 2012 Elsevier B.V.. Source


Bokowa A.,Odour Assessment | Beukes J.A.,Applied Plasma Physics AS
Water Science and Technology | Year: 2012

This paper will demonstrate the differences found in odour test results, when odour sampling is performed at the same sources by two different consultants. By examining two case studies, this paper will highlight that the difference between the results can be significant. Both studies are based on odour sampling programs determining the odour removal efficiency of odour control units installed at two different facilities: a pet food facility and an oil/grease recycling facility. The first study is based on odour measurements at the inlet and outlet of the unit installed by Applied Plasma Physics AS at the pet food facility. Odour assessments were performed by two separate consultants at the same time. The second study is based on testing of the odour removal effectiveness of two units: a scrubber and a biofilter at an oil/grease recycling facility. During this study two odour sampling programs were performed by two consultants at different times, but under the same process conditions. This paper will show how varying results can play a role in choosing the adequate odour control technologies. The final results suggest that although, an odour control unit may appear to be insufficient, it actually is successful at removing the odours. © IWA Publishing 2012. Source


Grant
Agency: Cordis | Branch: FP7 | Program: BSG-SME | Phase: SME-1 | Award Amount: 1.46M | Year: 2008

Within the last decade there has been significant growth in the use of egg products for both home and commercial use. The largest egg producing countries are China, the USSR, the US and Japan. The leading EU producers are The Netherlands, Spain, France and Italy. The Netherlands is the largest producer and exporter to EU countries. Despite this market share, various factors threaten EU producers, most prominent of which are zoonotic pathogens, namely Salmonella egg contamination. To date, a number of sterilisation methods exist for disinfecting eggs, including chemical, thermal and radiation methods. However, such treatments are not sustainable given that chemical products can be absorbed by egg shells, contaminate egg content and chemical washing of eggshells is not permitted in the EU for eggs destined for human consumption, thermal processes affect egg content or lead to shell cracking, slow pasteurisation is far too time-consuming for widespread use in the modern egg producing installation and irradiation of eggs is not permitted in the EU. Furthermore, SMEs lack the resources for developing a more advanced egg sterilisation technology. To this end, consortium SMEs have identified a clear need for a cost efficient and effective system for the secure sterilisation of eggs. The proposed EGGSTERILISATION will provide a highly effective system to sterilise eggs using a plasma source, a simple and safe microbial sterilisation technique, and contribute to reducing the high number of infections caused by this bacterium. The commercial objective of this EGGSTERILISATION proposal is to increase the competitiveness of SME egg producers and packers by providing them with a low cost, rapid and effective system that will be suitable for simple insertion into modern production or packing lines, facilitating installation and maintenance, thus saving time and associated costs.


Andersen K.B.,Applied Plasma Physics AS | Andersen K.B.,University of Aarhus | Glasius M.,University of Aarhus | Feilberg A.,University of Aarhus
Environmental Sciences: Processes and Impacts | Year: 2014

Odorous compounds identified in pig houses span a wide range of vapour pressures and may thus be present as volatile and semi-volatile compounds, but little is known about the partitioning between phases. In this study, the concentrations of 17 known odorants were measured in a pig house both in the gas phase and in particles. Particles were collected on PTFE coated glass fibre (GF) filters while gas phase compounds were collected using Tenax TA and Carbograph 5TD sorption tubes after the filtration. All samples were analysed using a thermal desorption gas chromatograph and mass spectrometer (TD-GC-MS). The effect of desorbing the filters at different temperatures (290, 200 and 100 °C) was investigated, and we found that a desorption temperature of 290 °C was optimal. Backup filters were placed behind the front particle sampling filter to account for adsorption of gas-phase compounds to the front filters (positive artefact). Adsorption of propanoic acid, butanoic acid and 4-methylphenol to GF filters and PTFE-coated GF filters was specifically investigated in the laboratory by measuring the air concentration with proton-transfer-reaction mass spectrometry. Both field and laboratory results show considerable adsorption of most compounds to filters, and the use of backup filters is necessary to account for this. Of the odorants investigated in this study, carboxylic acids (C4-C6) were the most abundant in the particles, which is ascribed to acid dissociation in the particles. The logarithm of the subcooled liquid vapour pressures, logp°L, plotted against the logarithm of estimated equilibrium gas-particle coefficients, logKp, showed that the compounds were divided into two groups, polar and non-polar compounds, that showed linear trends with mr-values of -0.94 and -0.83 respectively. The study shows that it is possible to measure gas-particle partitioning by filters and TD-GC-MS. Only very low concentrations and low fractions of odorants were found in the particles measured in the pig house. This journal is © the Partner Organisations 2014. Source


Grant
Agency: Cordis | Branch: FP7 | Program: BSG-SME-AG | Phase: SME-2 | Award Amount: 4.02M | Year: 2010

The problem and AirPath solution This project targets a large group of SMEs with a shared need. In Europe there are more than 50,000 broiler breeders who are facing a major problem concerning control of air- and insect-borne pathogens in their broiler houses, which results in high infection rates of the broiler flocks. This is partly caused by insects especially flies entering the broiler house through the ventilation system. The Airpath project seeks to solve this problem by developing a new type of barrier based on electrostatic precipitation. This is a known technology used in larger applications where cost is not a major concern such as chimneys on power plants. Hence, the technology must be further developed, scaled and adapted to the specific needs of the European broiler industry. Background of the project The project seeks to solve one of the major challenges that the poultry sector is facing concerning airborne pathogens. An example is Campylobacter which is a major problem in broiler houses (and in the consumer product). At certain times of the year (the warmer months) the breeders experience a rise of infection to more than 60-80% of the flocks. A previous study by DTU Veterinary Institute in Denmark has demonstrated that a major source of the infections is flies entering the houses through the ventilation system. DTU has demonstrated that by effectively keeping the flies out of the broiler houses, the number of infected populations will be drastically reduced. Using simple fly screens it was possible to reduce the infection rate to 15% of the flocs in the problematic period, whereas control populations not using screens showed more 50% infection rate.

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