The odors emitted from wastewater treatment plants are not only a health and hygiene problem, but can also lead to complaints from residents and have wider social ramifications such as bringing about falling property values in the surrounding area. In this paper, based on the data measured at domestic and overseas wastewater treatment facilities, the concentrations of complex odors and odorous compounds were compared for each treatment/process: primary treatment, secondary treatment, and sludge treatment processes. Odor compounds that contribute greatly to complex odors were summarized for each process. In addition, the characteristics of odor wheels for each wastewater treatment process, which provide both chemical and olfactory information regarding odors, were reviewed. For domestic wastewater treatment facilities, the complex odor concentrations (unit, dilution factor) of the primary and secondary treatment processes were 4.5-100,000 (median, 32.1) and 2.5-30,000 (median, 10.7), respectively. However, the complex odor concentrations in the sludge treatment process were 3.0-100,000 (median, 118.7), which was more than three times higher than that in the wastewater treatment process. In the wastewater treatment process, those odor compounds making the greatest contributions to complex odors were sulfur-containing compounds such as hydrogen sulfide, dimethyl sulfide, and dimethyl disulfide DMS. In order to properly manage odors from wastewater treatment plants and minimize their impact, it is important to understand the status of odor emissions. Therefore, the compositions and concentrations of odors from wastewater treatment processes and odor wheel information, which are reviewed in this paper, are used to evaluate the potential risk of odor from wastewater treatment facilities in order to derive strategies to minimize odor emissions. Moreover, the information can be usefully used to introduce the best available technology to reduce odors emitted from wastewater treatment facilities.

This study evaluated the effectiveness of odor reduction when spraying inside the Bio-curtain (hereinafter referred to as curtain) according to the exhaust fan operating rate. Spraying is a main factor affecting the ability to odor reduction of curtains. The curtain (total area: 37.9m3) was constructed with two layers of light-shielding screens stretched over a rectangular parallelepiped structure installed around an exhaust fan (630 mm) on the side wall of a pig barn. Air samples for odor analysis were collected from inside the pig barn and outside the curtain. The main odorous compounds such as volatile fatty acids, phenols, indoles, and ammonia were measured. The odor reduction effectiveness was evaluated by total odor activity values (TOAVs) summed to the odor activity values of each odorous compounds. Depending on the exhaust fan operating rate, the reduced rate of TOAVs gradually decreased to the range between 15.67% and 68.80%. Because the contact time between the spraying liquid and the air velocity of the exhaust fan becomes shorter (or there is a reduction in liquid to gas flow ratio) as the exhaust fan operating rate increases. The results of this study can be used as basic data for research into spraying conditions to improve the odor reduction effectiveness of curtains.

Odor is a type of air pollution where irritating substances enter through the olfactory system, causing discomfort. At present, the government is formulating various measures and policies to address this type of pollution. This paper seeks to analyze major research cases from both domestic and overseas settings in relation to odor management. In addition, it reviews the potential of addressing environmental issues using a living lab approach in conjunction with community mapping and citizen science. For example, in one domestic case, the Magok smart city living lab project, citizens’ data on community mapping of odor were collected for analysis using artificial intelligence (AI) to derive results. Additionally, in an overseas case in California, citizens directly participated in monitoring air quality using the Community-based monitoring (CBM) method, and both CBM and existing methods were used to assess the level of pollutants for effective data collection. In both of these cases, the potential to address environmental issues was seen to manifest through the development of citizens’ determination and ability to independently solve local problems. However, there are still problems in implementing citizen science, such as the lack of infrastructure and resources available, issues with data collection methodology, questions of objectivity regarding collected data, and concerns about sustainability and expertise in relation to civic participation. Addressing these problems would require an institutional foundation and systematic civic education. This study highlights the potential of addressing environmental problems inherent in the living lab system based on citizen science by analyzing two cases. In addition, this study suggests that if systematic civic education measures are introduced to address issues within existing citizen science research approaches, such measures would be valuable within the educational living lab framework in that they would become effective in tackling not only environmental problems but also social problems as well.

This review paper aimed to comprehensively assess the ventilation methods and ventilation rates of livestock sheds, various livestock odor mitigation technologies, and the design flow rate of odor mitigation devices. The most efficient ventilation method for livestock odor control was found to be mechanical ventilation. When livestock odor is at its most severe during summer, ventilation systems are operated at the maximum ventilation rate, which is 5-25 times higher than the ventilation rate in winter. Therefore, the mitigation facilities of livestock odor must be designed while considering the maximum ventilation rate. There is a significant amount of research data on various livestock odor control technologies using various physical, chemical, biological, and complex technologies applied to livestock farms. Biofiltration and photocatalytic oxidation are considered the most promising methods due to their cost-effectiveness and simplicity. Biofiltration is effective for removing hydrophilic odors, but requires improvement for the efficient removal of hydrophobic odors and the control of accumulated excess biomass. The advantages of the photocatalytic oxidation method include its excellent hydrogen sulfide and ammonia removal rates and relatively low ozone emissions. However, it requires technology to reduce nitrous oxide emissions. Investment in installing and operating these odor mitigation technologies is only realistic for large-sized farms. Therefore, it is imperative for small and medium-sized livestock farms to develop odor mitigation technology that is inexpensive and has low installation, operation, and maintenance costs.

아메리카동애등에(H. illucens)는 음식물 폐기물 등 유기성 폐자원을 효율적으로 처리할 수 있는 능력을 가지 고 있어 전세계적으로 주목받고 있는 환경정화 곤충이다. 하지만 유기성 폐자원을 처리 시 가장 큰 문제는 아메리 카동애등에가 먹이인 유기성 폐자원을 소화시킬 때 발생되는 악취이다. 국내에서 현재 아메리카동애등에를 사육하고 있는 농가는 223호로 조사되고 있지만 이중 악취발생 저감장치 등을 설치한 농가는 10%가 안되는 것으 로 생각된다. 따라서 국내에서 동애등에 먹이로 가장 많이 사용되는 습식사료를 먹이로 사용하였을 때 농가 사육 장 안에서 발생되는 복합악취와 지정악취 22종에 대하여 분석하였다. 그 결과, 복합악취는 249배였으며, 지정악 취는 22종 중 7종(암모니아, 메틸메르캅탄, 트라이메틸아민, 아세트알데하이드, 프로피온알데하이드, 뷰틸알 데하이드, i-발레르알데하이드)가 검출되었다. 이중 가장 높은 농도를 나타낸 악취물질은 암모니아로 98.4ppm 이 분석되었다. 또한, 아메리카동애등에를 사육 시 가장 많이 발생되는 암모니아의 발생시기는 사육초기인 1~4 령보다 5령 이후 전생육기 중의 대부분을 발생시키는 것으로 조사되었다. 이러한 결과는 암모니아 저감을 위한 적정시기를 설정하는데 도움이 될 것으로 생각된다.

This study examines the correlation between livestock odor civil petitions and the establishment of malodor control areas in Jeju Special Self-Governing Province, focusing on swine farms where numerous civil petitions regarding malodors have been received. After the designation of the malodor control areas, high odor concentrations occurred in Aewoleup and Jocheon-eup, and the odor concentration decreased in other areas. The number of civil petitions shows a consistent annual trend, with increased petitions from March, peaking during summer (July and August), and decreasing from September into winter. In Jeju-si, there were many civil petitions in Hallim-eup and Aewol-eup where there were many malodor control areas. However, in Seogwipo-si, there were also many civil petitions in Pyoseonmyeon, where there is no malodor control area. Additionally, we compared the average multiple of compound malodors and the rate of exceeding the maximum allowable emission level for compound malodors with the number of livestock malodor civil petitions to assess the actual state of malodors. The results reveal a stronger correlation between the number of civil petitions and the rate of exceeding the compound malodors allowable emission level than the average multiple for compound malodors. These findings provide valuable insights into addressing livestock odor concerns and enhancing malodor control measures in Jeju Island.

The air dilution olfactory method to measure complex odors needs to store and carry odor samples from the field sampling until the analysis in laboratories. Until the analysis of sample in the laboratory, odor dilution factor (odor sensitivity) in the sample bag may decrease over time depending on the characteristics of each odor substances. This is one of the limitation for the air dilution olfactory method. Thus, the air dilution device enable to measure without loss in complex odors of samples. Recently, many studies on the performance test of on-site air dilution devices, i.e., field olfactometer, has been conducted to figure out the feasibility of the field olfactometers. In this study, seven odor samples were collected from five odor emission source sites. And comparative analysis with the air dilution olfactory method was carried out to assess the field applicability of the olfactometer. As results, the performance of the field olfactometer used in this study is regared as the affordable method. The dilution factors from between two methods showed the similar values, indicating low values of standard deviations. In order to ensure the accuracy and precision of measurement data using the field olfactometer, methodology minimized variables (that may affect measurement) needs to establish.

In this study, we analyzed the changes in concentrations of volatile fatty acids (VFA), phenols, and indoles, as well as odor contribution in pig slurry. The pig slurry was stored for approximately two months after the manure excretion of pigs which had been fed 3% level of peat moss additive. The investigation was carried out through lab-scale experiments simulating slurry pit conditions within pig house. Throughout the storage period, the concentration of VFA exhibited a tendency to be 11%-32% higher in the pig manure treated with peat moss as compared to the control group. From a concentration perspective, phenol and acetic acid accounted for the majority of the total odor compounds produced during the pig slurry storage period. However, their significance diminished when the concentration of odoros compounds are converted into odor activity value and odor contribution. Despite the odor reduction effect of the ammonia (NH3) adsorption by peat moss, if it cannot effectively reduce the high odor-contributing compounds such as indoles and p-cresol, the sole use of peat moss may not be considered an effective means of mitigating odors produced by pig slurry. According to this study, indoles, p-cresol, skatole, and valeric acid were consistently revealed as major odor-contributing substances during the two-month storage of pig slurry. Therefore, a comprehensive odor mitigation methodology should be proposed, taking into consideration the odor generation characteristics (including temporal concentration and odor contribution) of pig slurry-derived odors during storage.

This review comprehensively summarizes the livestock odor reduction method by dietary manipulation, in-housing management, and manure management. The gut microbial metabolism of animals can be stimulated by low-crude protein feeding and the addition of probiotics, enzymes, plant extracts, and/or organic acids to their feed. These methods can result in reduced odor emissions from manure. For in-housing management, it is important to maintain the proper breeding density in the barn facilities, regularly remove dust and manure, and periodically clean the barn facilities. A barn using litter on the floor can reduce odor at a relatively low cost by adding adsorbents such as zeolite, biochar, etc. Although masking agent spraying can be the simplest and quickest way to control odors, it is not a fundamental odor mitigation strategy. Odor emissions can be reduced by installing covers on manure slurry storage facilities or by acidifying the manure slurry. It is necessary to install a solid-liquid separator in an enclosed facility to minimize odor emissions. Other methods for reducing odor emissions include covering manure composting plants with semi-permeable membranes or using reactor composting technology. In order to minimize odor emissions in the liquid manure composting, sufficient oxygen must be supplied during the fermentation process. Furthermore, the odor reduction effect can be achieved through the liquid manure pit recharge system which supplies matured liquid manure fertilizer to the slurry pit in the pig house.

This study investigated the odor emission characteristics of fertilizer manufacturing facilities. The characteristics were evaluated by measuring the odor concentration at the outlet and site boundary of the complex fertilizer and organic fertilizer manufacturing facilities. The evaluation process utilized the air dilution sensory method and PTR-ToF-MS. The complex odor dilution factor ranged from 100 to 120 times at the outlet of the compound fertilizer manufacturing facility. Specifically, the concentrations of Ammonia and Aldehydes were relatively high as designated odor substances. For the organic fertilizer facility, the dilution factor for complex odors was measured up to a maximum of 3,000. And, designated odorants such as Ammonia and Hydrogen sulfide were measured at levels up to parts per million (ppm). The odor contribution assessment of the fertilizer manufacturing facilities showed that the complex fertilizer facility exhibited similar contributions from Aldehydes and Sulfur compounds. On the other hand, the organic fertilizer facility had the highest contribution of over 62% from Sulfur compounds. As odor substances are easily changed and diffused according to weather conditions, it is difficult to obtain representative data according to the measurement time. Therefore, if continuous monitoring of odorous substances is performed using equipment that can be measured in real time without pretreatment, it becomes feasible to identify odor emission sources and regional spatio-temporal distribution. This information would then serve as a basis for analyzing odorant contamination characteristics and establishing appropriate countermeasures.

In this review paper, the sources of odor, major odor compounds, and emission characteristics from livestock farms are summarized. The main sources of odor on livestock farms are barn facilities, manure storage facilities, manure composting facilities, and wastewater treatment facilities. High concentrations of odor are emitted during the manure removal process, and livestock odor tends to be the most severe in summer. There was a remarkable difference in odor intensity depending on the farm size and the cleaning condition, and odor intensity varied greatly depending on the weather parameters such as wind direction and speed. The concentrations of ammonia and hydrogen sulfide were high among the odor compounds emitted from livestock farms, and these compounds also contributed to odor intensity. The odor intensity in poultry and swine farms was higher than in cattle farms. Information on livestock odor emission is very useful for managing livestock odor complaints and designing odor abatement technologies.

The livestock industry continues to grow around the world, but livestock odor is becoming an environmental problem that is difficult to solve. In this review paper, the current status of the domestic livestock industry, livestock odor complaints, mediation cases involving environmental disputes related to livestock odor, livestock odor management policies and standards, livestock odor sources, major odor compounds, and emission characteristics are summarized. Domestic meat supply and meat consumption per capita are increasing, and livestock farms are becoming large-scale and intensive. Livestock odor complaints increased 4.5 times over the last five years (2014-2019), and its proportion to total odor complaints was 19%-30%. Livestock facilities larger than a certain size are classified as odor emission facilities and are managed based on the Odor Prevention Act. The information presented in this paper can be used to establish strategies to promote the sustainable development of the livestock industry while resolving air quality deterioration and public health problems caused by odor emissions from livestock farms.

This study was carried out in order to provide suggestions with regard to optimal control methods for various odor emission facilities (162 companies and 26 industrial classifications) through comparative analysis of effective odor treatment technologies for each type of odor substance by literature reviews, based on measured 22 odor substance data for 162 samples taken from A city. The industrial classification of Pulp showed the highest odor quotient (7,589 as average value) and was followed by the industrial classifications of Wastewater, Woods, and Furniture, indicating average odor quotient values of 2,361, 1,396 and 1,392, respectively. Absorption using chlorine dioxide and sodium hydroxide can be an optimal treatment method to remove the odor substances of sulfide and aldehyde groups. Biofilers with microbial communities will be effective to remove odors caused by volatile organic compounds (VOCs) and an absorption method using sulfuric acid is proper for the removal of odor substances caused by nitrogens.

Korea is a country where the population is concentrated in metropolitan areas that have undergone rapid industrial development. As of 2020, more than 43% of the total population lives in large cities, and about 18.5% of the total population lives in Seoul. A basic human need living in such a metropolis is a pleasant environment. In this study, complex odors and designated odors were evaluated at the boundary areas and at the outlets for 15 public environmental facilities selected from among odor sources in Seoul. As a result of measuring the complex odor intensity was 3 ~ 6 times at the boundary areas and 100 ~ 4,481 times at the outlets. In food waste treatment facilities, incineration facilities, and waste transfer station facilities, the compound making the largest contribution to odor is acetaldehyde, which was recorded at 46%, 25%, and 32% respectively. At a sewage treatment facility and agro-fisheries wholesale market, hydrogen sulfide was the largest contributing compound at 71% and 29% respectively.

Complaints about foul odors are emerging as an issue, and the number of complaints is steadily increasing every year. Biofiltration is known to remove harmful or odorous substances from the atmosphere by using microorganisms, and full-scale biofilters are being installed and operated in various environmental and industrial facilities. In this study, the current status and actual odor removal efficiency of full-scale biofilters installed in publicly owned treatment facilities such as sewage, manure, and livestock manure treatment plants were investigated. In addition, the effects of design and operating factors on their efficiency were also examined. As a result, it was found that odor prevention facilities with less than 30% odor removal efficiency based on complex odors accounted for 40%-50% of the biofilters investigated. In investigating the appropriate level of operating factors on odor removal efficiency, it was found that compliance with the recommended values p lays a significant role in improving odor removal efficiency. In the canonical correlation analysis for the on-site biofilter operation and design data, residence time and humidity were found to be the most critical factors. The on-site biofilter operation and design data were analyzed through canonical correlation analysis, and the residence time and humidity maintenance were found to be the most important factors in the design and operations of the biofilter. Based on these results, it is necessary to improve the odor removal efficiency of on-site biofilters by reviewing the effectiveness of the operation factors, improving devices, and adjusting operating methods.

The types and distribution ratio of odor removal systems installed in publicly owned environmental facilities such as sewage treatment, wastewater treatment, manure treatment, livestock manure treatment, and food waste treatment were investigated. Since the intensity of the odor and the composition of the odor substances are different depending on the type of each public treatment facility, different odor removal efficiencies were derived depending on the applied odor removal technology. In addition, the removal efficiency of complex odors and individual odor substances of odor removal systems such as those applying biofilters, scrubbers, and adsorption towers were also compared and evaluated. Although it depends on each odor removal technology and application facility, about 50% of various odor removal systems presented an odor removal performance of less than 30%. The odor removal systems with an odor removal efficiency of 70% or more were evaluated to be less than 30% of the total number. Therefore, we suggest that odor removal efficiencies should be improved through continuous monitoring, diagnosis, reinforcement of maintenance, and improvement of systems.

The distance between livestock facilities and residential spaces is decreasing. Moreover, livestock odor complaints are increasing due to the large-scale and concentrated livestock breading industry. In order to reduce odor from livestock facilities, bio-curtain that are easy to install and inexpensive are commonly used in Korea. However, there is a lack of basic data on design standards and operation manuals for bio-curtains. The installation density of the bio-curtain material is an important factor that affects the odor reduction rate, increment of the load on the ventilation fans, and the structural stability of the curtain. There are limitations on deriving the design conditions of the bio-curtain by only field experiments targeting invisible air. Therefore, aerodynamic simulation such as CFD (computational fluid dynamics) can be used to obtain quantitative data according to various environmental conditions. Bio-curtain is a porous medium with a complex structure, and it is necessary to derive aerodynamic coefficients to analyze it. In this study, the wind speed and pressure difference according to the design density of the bio-curtain were monitored using the experimental chamber. Using the field results, a pressure resistance curve was created for each flow velocity and installation density. The viscosity and resistance coefficient of the bio-curtain were calculated through the derived resistance curve.

Incheon is an area where complaints about odors occur frequently and there are many sources of odor emission. In this study, we used a real-time monitoring device to measure the odorous concentration near the areas where there are complaints about odors. The measurements were carried out for the three areas (G, C, S) that are located around emissions sources. G is situated in an industrial complex that has a reputation for being one of the most foul smelling regions of Incheon. A petroleum refining plant and storage facility are located around C. S is a residential area nearby an industrial site. The concentration of major designated odor substances in the G and S areas satisfied the site boundary emission standards. With regard to the characteristics of odor substances by region, although the C area region had the highest odor intensity among the three regions due to the odor intensity near the oil storage facility areas G and S were similar in terms of odor intensity. In the region of the G area, the odor intensity was slightly higher at the northern side of t he industrial complex. In terms of the odor intensity of the designated odor substances, trimethyl amine was the strongest, followed by hydrogen sulfide. The real time monitoring system was necessary to analyze the changing trends of odor substances and for the determination of major odor sources. This study was conducted to identify the material causes of odors in areas of Incheon where there are frequent complaints about major odors.

The annual number of odor complaints increased about 10 times over 14 years from 4,302 in 2005 to 40,854 in 2019, in Korea. Especially, livestock facilities account for more than 50% of the odor complaints and the swine farms account for the most odor complaints among livestock. It is therefore necessary to manage swine farms as the major odor emission source. In this study, a real-time odor monitoring system equipped with PTR-TOF-MS (proton transfer reaction time-of-flight mass spectrometric) was used to measure the odorous substances in two swine farms. Odorous substances emitted from outlets were sampled and measured at the two types of swine farms. In addition, the boundary spots were designated as measurement points. As a result, the rankings of the odorous substances in order, from highest to lowest, were ammonia, acetaldehyde, methyl mercaptan, fatty acids, etc. and the level of odor intensity was 0.8-4.4 at the outlet of the swine farms. The concentration at the boundary decreased between 1/100 ~ 1/10000 compared to the concentration emitted from outlets. Base on the results of evaluating odor activity values, Skatole and p-Cresol were estimated as major odor substances in swine farms.