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.

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.

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.

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.

In this study, actual odor conditions were investigated in restaurants, livestock facilities, and major odor discharge facilities around daily life, and an odor modeling program was performed to find ways to improve odors in odor discharge facilities. The odor modeling results of restaurants around daily life showed that the complex odor concentration of large restaurants, which are close to residential areas, is higher than the acceptable complex odor standard at the receiving point. It was judged that a plan to increase the height of the restaurant odor outlets and a plan to reduce the amount of odor discharge was necessary. As a result of modeling the life odor of livestock housing facilities, when the distance from the housing facility is far away, the actual emission concentration is much lower than the acceptable emission concentration at the receiving point. It was judged that such facilities need to be reviewed for ways to reduce the emission of odorous substances, such as sealing the livestock housing facilities or improving the livestock environment. The main odor emission business sites that show complex odor concentration as 1,000 times or greater than the outlet odor emission standard were businesses associated with surfactant preparation, compounded feed manufacturing, textile dyeing processing, and waste disposal. Due to the separation distance and high exhaust gas flow rate, it was found that odor reduction measures are necessary. In this study, it was possible to present the allowable odor emission concentration at the discharge facilities such as restaurants, livestock houses, and industrial emission facilities by performing the process of verifying the discharge concentration of the actual discharge facility and the result of living odor modeling. It is believed that suitable odor management and prevention facilities can be operated.

In Korea, odor emission control is carried out at the boundary between the discharge port and the site based on the height of the discharge port, but in Japan and the U.K. a range of characteristics are considered in odor management, including the height, size, and amount of exhaust gas, when managing the acceptance criteria of the discharge port that conforms to the odor concentration standards based on the site boundary. In this study, the permitted concentration of odor in the outlet was studied considering the design conditions of the outlet, in order to manage it based on the distance between the outlet and the residential area. To improve the effectiveness of odor management, Korean odor management measures were reviewed by applying the methods used to calculate odor concentration in Japan and the U.K. Guidelines on effective odor reduction were provided by calculating the permissible odor concentration for each condition based on the flow rate and height of the final outlet to comply with the permissible concentration at regular intervals at the outlet of the factory.

The number of complaints of odor in urban area has been increased due to mixed industrial areas of odor-related factories and municipal waste treatment odor-producing facilities located in adjacent residential regions. In this study, the characteristics of odor were reviewed according to two types of complaint from regions in Incheon area. In this study, the characteristics of odor were reviewed in two patterns of odor complaints in Incheon area such as the complaints are maintained high continuously and are increased in recent period. International city with largescale residential areas with the environmental facilities and redevelopment of residential regions with the adjacent industrial complexes and other odor emission sources were analyzed. Based on these characteristics, the odor management measures of major odor generating sources in order to improve urban environment were discussed with reducing odor complaints effectively.

The study of odor generation conditions in urban areas which were outside odor controlled(or management) areas were investigated using the air dilution olfactory method and instrumental analysis in Incheon city. From the study the generation of odor from residential sources and industrial sources was different from region to region. Odor intensity was high in industrial regions in the afternoon, but was low in school regions in urban areas. From the analysis, more effective regional policy suggestions to address different kinds of odor problems in urban areas are proposed.

본 연구에서는 도시지역의 악취발생에 대하여 인천지역의 악취관리지역 이외 지역인 도심지역을 대상으로 관능법을 이용한 시민 모니터링을 통하여 조사를 진행하였다. 조사 결과 지역에 따라 지역별로 생활악취와 산업부분 악취발생이 서로 다르게 나타났으며 시 간별로는 대부분 저녁이나 아침시간대에 세기가 강한 악취를 감지할 수 있었다. 이러한 분석의 결과를 갖고 도시지역으로서 악취관리지역 이외의 지역에 대한 악취 문제를 해결 하기 위한 방안을 검토하고 실천방안을 제시하였다.

본 연구에서는 공공하수처리시설의 효율적인 관리방안 제시를 위하여 2008년~2010년까지 28개소의 공공하수처리시설에 대하여 복합악취와 지정악취물질(22종)을 대상으로 악취실태조사 및 원인분석을 실시하였다. 조사결과 전처리 공정과 슬러지 처리공정에서 주로 고농도의 악취가 발생되고 있었으며, 황화수소와 메틸머캅탄 등의 황화합물류가 주요 악취원인물질로 조사되었다. 공공하수처리시설에서 발생되는 악취는 유입수의 성상에 따라 차이가 있으며, 유입수에서의 복합악취는 67배~66,943배, 황화수소는 ND~66.87 ppm으로 조사되었다. A 하수처리시설 유량 조정조에서의 복합악취와 황화수소는 교반시 각각 3,000배, 6.23 ppm, 비교반시 각각 300배, 0.20 ppm으로 조사되었다. 유입 분배조와 생슬러지 분배조는 하수와 슬러지 이송 파이프 라인의 낙차에 의해 내부에 양(+)압이 형성되므로 파이프 라인의 연장과 악취포집설비를 정상적으로 설치․운영하여 내부를 음(-)압 상태로 유지할 필요가 있다.