This study was performed to obtain the emission characteristics of odor compounds generated from a livestock wastewater treatment process. The sampling of odor compounds was performed twice, on May 9th and June 14th 2006, at 4 and 5 sites in the boundary and source areas, respectively. The odor concentrations obtained from the air dilution sensory test ranged from 10 to 100 in the boundary area. Of the 5 source sites, the odor concentrations found at the pre-treatment building had the highest values, which were 14422 and 20800 for the first and second dates, respectively. To estimate the major odor compounds produced during a live wastewater process, the contributions of 12 odor compounds to the total odor were calculated from the concentration and odor threshold values of each compound. At the pre-treatment building and outlet of the activated carbon tower of the source sites, the contribution of sulfur compounds to the odor was 97%, and at the outlet of the biofilter that of NH₃ was 90%. The order of the contribution to the odor in the boundary area sites was; from highest to lowest: H₂S, C₂H₆S, i-C₅H10O, C₃H₉N, NH₃. The correlation coefficient between the theoretical odor concentration from the odor threshold of 12 odor compounds and that obtained from the air dilution sensory test was 0.73. This result indicated a limit to the correct analysis of the odor concentration obtained from the air dilution sensory test when only 12 odorous compounds at a livestock wastewater treatment process are used. The odor removal efficiency of the deodorization facilities showed that for the activation carbon tower, the odor concentration was reduced to 4% and the contributions of H₂S, C₂H₆S and NH₃, which were estimated to be the major odor compounds, were reduced to 20, 26 and 11%, respectively. With respect to the bio-filter, the removal efficiency of the odor compounds revealed an odor concentration of 0% because the major odor compounds were calculated as negative percentages.

The aim of this study was to investigate the legally-designated malodorous compounds at the plant boundary areas of 5 plants expected to emit high odor intensities, as well as! complaint area at the Yeosu petrochemical industrial complex in Korea. The sampling was carried out during spring and summer of 2003 and 2006. The concentrations of ammonia, sulfur compounds (hydrogen sulfide, methyl mercaptan, and dimethyl sulfide) and aldehydes (acetaldehyde and propionaldehyde) emitted during 2006 were higher than those emitted during 2003, and the concentrations emitted during summer were higher than those emitted during spring at the plant boundary areas. It was thought that the concentrations of odorants in the complaint area had been directly influenced by the concentrations of odorants in the plant boundary areas as they showed similar patterns of concentration variations. While the concentration of TMA during 2006 was lower than during 2003 at the all sampling sites, the concentration of styrene during 2006 was higher than during 2003 at the all sampling sites. The sites showed high concentrationsof odorous compounds at the plant boundary area of the related chemical and petrochemical refinery plants.

In order to validate the meteorological and odor dispersion modeling methods, the measured meteorological parameters such as wind speed and direction and odor intensities were compared with those calculated from the models. The CALMET and CALPUFF models which were recommended by USEPA were used to predict the meteorological variable and odor concentrations. The average time of odor concentration was 10 mins. to consider instantaneous response nature of the odors. The results showed that model predictions were in good agreement with the measurements. It is expected that the modeling method presented in this paper will be useful to assess the impact of odors from industrial complex to near-by residential areas.

The odorants from wastewater sludge treated with four different chemical oxidants, i. e., potassium ferrate, sodium hypochlorite, sodium permanganate, and calcium nitrate, were analyzed. The release of odorants from the treated sludge was not completely eliminated, only retarded, possibly due to the low one time doseof oxidants. In a comparison of the concentration profiles of methyl mercaptan and dimethyl sulfide, calcium nitrate was the best of the four different oxidants at reducing their emission. For methyl mercaptan, calcium nitrate gave the best result, while for dimethyl sulfide, potassium permanganate was found to be the best oxidant. From this study, it was found that the oxidation-reduction potential (ORP) would be an easy and inexpensive parameter for the monitoring of the release of offensive odors.

In this study, QA/QC (quality control/quality assurance) data of reduced sulfur compounds from several institutes were obtained and compared based on the Korean standard method for off-odor. From the results, attempts were made to optimize the analytical conditions and improve the measurement reliability of reduced sulfur compounds analyses from detailed CF/TD and GC/PFPD information. Analysis results (minimum detection limit, precision, recovery rate) of reduced sulfur compounds based on the each analytical condition corresponded with the Korean standard methods for off-odor. Therefore, we expect that we could execute the exact analysis if we use the analytical condition of CF/TD and GC/PFPD in this study

Experiments were conducted to analyze the concentration of sulfur compounds present in ambient air at the pg or ppt level. The compounds were estimated using GC/PFPD (Gas Chromatography with Pulsed Flame Photometric Detector) analyses with a Thermal Desorber (TD). The analytical results showed very stable and precise retention time values (RSD: ＜ 0.22%), peak area (RSD: ＜ 3.9); the coefficients of the calibration curves were also determined (r²: ＞ 0.991). Also, with respect to the recovery rates of the sulfur compounds from dry air, those for H₂S, MM, DMS and DMDS were 94, 100, 113 and 114%, respectively. In order to evaluate the sulfur chemicals in humid air, a study was conducted at RH of 55 and 100%. The recovery rate at a relative humidity of 55% was similar to that under dry conditions. However, recovery rates of H₂S and MM at RH 100% were reduced to 70 and 77%, respectively.

DOAS (Differential Optical Absorbance Spectrometry) has been designated as one of the instrumental analyses for the continuous and real time measurement of ammonia and styrene under the newly established Korean Offensive Odor Prevention Law. However, cases of odor monitoring using DOAS are very limited, as questions have been raised relating to its reliability, mainly for ambient monitoring. This paper primarily focused on the advantages and limitations of DOAS for the measurements of ammonia and styrene, with a review of the theoretical and field intercomparison studies, to address its suitability, particularly for odor monitoring purposes. However, this instrumental technique was found to be useful for real time continuous measurements of concentrations over a few ppbv, for both ammonia and styrene, and was also found to be sensitive enough for odor monitoring purposes over vast multi industrial complex regions.