Characterization of the odor emissions resulting from food fermentation process and organic chemistry industry

Odor as a parameter has recently become an important contamination parameter with the increasing wellbeing level and it is necessary to minimize the problems caused by volatile organic compound which is the primary reason of this unpleasant odor. Waste gases with odor generated in the processes particularly as a result of industrial activities are being emitted to atmosphere in an uncontrolled manner, therefore causing odor emission related issues in the immediate area. Fermentation processes in the food industry and the organic chemistry industry, two of the processes which involve aforementioned odor emissions, were addressed in this study thus made it possible to characterize the odor emissions caused by these industries. An active sampling was conducted based on the principle of air flow in sorbent tubes using a pump system in order to efficiently sample UOBs. Sorbent tubes containing 20:35 Tenax-TA™, 60:80 Carboxen™ 1000, and 60:80 Carbosieve™ SIII sorbents were used during the sampling which facilitated the adsorption of UOBs generated during the food fermentation process which are highly volatile under low vapor pressure. The GS/MS system was supported with TD in order to convey UOBs into the GC/MS system in the best way possible and to have representative measurement results from them. Thus, the UOBs sampled on the sorbent tube were desorbed under high temperatures and conveyed into the GC/MS system. The food fermentation process in question results in the emission of gases containing UOBs such as ethanol, acetaldehyde, and 1-propanol to atmosphere therefore causing the odor problem. In this context, volatile compounds of alcohol which account for more than 99% of the emissions causing this odor in the fermentation process were analyzed. Theoretical emission calculations were made based on the literature in order to identify the process-borne emissions and results were compared with the analytical analysis results. A total of 5 samplings were conducted for the selected fermentation process. It was found that the most convenient and representative results were obtained from the analyses conducted on the samples collected in 50 ml and 20 ml, as a result of the first 3 sampling procedures which involved volumes of 1000, 100, 50, and 20 ml. In the light of these results, it was found that an emission of 130 mg/m3 was released to atmosphere. Emission characterization of the fermentation process for the 17th hours was obtained from the 4th and 5th sampling procedures. Sampling was conducted for the volume of 20 mL from a fermantor at the beginning of each hour in order to present the waste gas characterization of the process for the 17th hour. As a result of the analyses, it was found that the amount of ethanol sampled for calibration was above the identified range and that it would predict the increased margin of error. It was estimated that a sample volume of 10 mL would give results in the calibration range allowing for measurements of the emission sampling of the 17th hour. As predicted, all the analyses results obtained from 17th hour sampling were within the calibration range. According to the results obtained, the measurements showed that the first hours of the fermentation process were accountable for emission concentrations varying between 1000 mg/m3–1200 mg/m3 for the UOBs in the alcohol group. Emissions declined dramatically after the 10th hour of fermentation. It was observed that the cycle was completed as of the 13th hour of the process and the emission rate was negligible until the 17th hour. An olfactometry testing service was employed in order to identify the subjective perception of the emissions resulting in unpleasant odor and the results were compared with the literature data and discussed. Waste gas characteristic of the fermentation process found to involve 70-75% ethanol emissions, 25-30% acetaldehyde emissions and ≤ 5% other UOBs such as acetone and propanol. The manufacturing plant was selected in order to represent the organic chemistry industry and field visits were paid and authorized personnel were interviewed in order to understand the manufacturing processes. Thee information gathered showed that the main emissions of this plant involved TMA, a volatile organic compound. Nevertheless, it was found that UOBs such as dimethylamine, trimethylamine, and dimethylsulfoxide contributes to the emissions in a negligible amount. Adsorption of organic chemistry industry borne methylamine compounds such as dimethylamine and trimethylamine on the sorbent material was investigated. As a result of this investigation it was found that sorbent materials such as Carbopack™, Carbosieve™, and Carboxen™ were insufficient in the adsorption of methylamine compounds even though they have a greater specific area. The reason behind this finding is the grain size which is of great importance when selecting the sorbent. Pressure loss along the sorbent tube reaches to a very high level and it fails to adsorb methylamine compounds as the grain size of sorbent material such as Carbopack™, Carbosieve™, and Carboxen™ is relatively smaller. Tenax™ TA filling material stands out with its efficiency in analyzing compounds of the amine group when the literature is reviewed. Sorbent tubes filled with Tenax™ were reported for their reliable results in the measurements of methylamine compounds when used in combination with thermal desorption system. Another purpose of this study was to create local manufacturing technologies in order to reduce dependence of foreign technologies, allowing for domestic production. Accordingly, supporting materials other than the sorbent filling material such as cast, filter material and glass wool were provided in order to produce a locally engineered sorbent tube. Thus, the sorbent tubes used in the TD/GC/MS analyses were manufactured locally except the filling material. Tenax-TA™ (20:35 mesh) and locally manufactured Tenax-TA™ (60:80 mesh) were injected with a standard concentration and readings were made for both tubes in line with their specific calibrations in order to compare the accuracy of the measurements conducted using these tubes prior to the analyses. Adsorption of the material on each tube was compared and the adsorption of TMA was found to be 5-10% higher in the original tube while DMA showed the same amount of adsorption for the same amount of loadings. This differentiation was accounted for the changing grain size of the same material. Following the preliminary procedures and the calibrations, 3 samplings were performed in different time intervals in the selected organic chemistry manufacturing plant. Waste gas sampling was performed for 20, 50, 100, and 250 ml and analyses showed that the 50 ml sample gave the best results. The sampling was performed on a line with 100 m3/h capacity and a TMA emission of 44 mg/m3 was detected. Thus, it adds up to a daily TMA emission of 1056g. An olfactometry testing was also performed in line with the service employed in parallel with the analytical measurement. The olfactometry analysis revealed the existence of a high level of odorous gas emission up to 19863 KB/m3.