In this study, hybrid devices were developed to simultaneously remove odor and particulate matter (PM) emitted during meat grilling, and their performance was evaluated. A ceramic filter system and surfactant microbubble plasma system were used to reduce particulate matter. For odor reduction, an electro-oxidation system, an ozone-active catalytic oxidation system, and a multi-adsorption filter system were used. By combining the above particulate matter reduction and odor reduction devices, the reduction efficiency of odor and particulate matter generated during meat grilling was analyzed. As a result, most of the six combined device conditions showed a reduction efficiency of more than 90% for particulate matter. The combined odor also showed a high reduction efficiency of less than 200 times the emission concentration standard. This study also evaluated 22 types of odorous substances, of which ammonia (NH3) and hydrogen sulfide (H2S) showed removal efficiencies of more than 99%. Therefore, it is expected that the combination of these technologies can be used and applied directly to the sites where meat grilling restaurants are located to effectively contribute to the simultaneous reduction of particulate matter and odor.

This paper aims to review the odor removal performance and operating parameters of pilot and full-scale chemical scrubbers, bioscrubbers, biofilters, and biotrickling filters for odor control in wastewater treatment plants. Based on the performance of full-scale facilities installed in wastewater treatment plants, empty-bed residence times were the shortest for bioscrubbers (7.5±2.5s), followed by chemical scrubbers (20±8.1s), biotrickling filters (22.2±26.2s), and biofilters (48±30s). The removal efficiencies of complex odors by biofilters, biotrickling filters, bioscrubbers, and chemical scrubbers were 97.7±1.9%, 87.7±15.6%, 89.0±9.0%, and 70.0%, respectively. The investment cost was the lowest for biofilters, followed by biotrickling filters, bioscrubbers, and chemical scrubbers. In addition, the operating costs of these deodorization technologies were in the following order: biofilters < bioscrubbers and biotrickling filters < chemical scrubbers. However, most studies on odor control for wastewater treatment processes have been conducted on a laboratory scale with model odors (single odorous compound or mixtures of 2-3 odorous compounds). Therefore, field research to develop deodorization technologies for wastewater treatment plants should be more actively conducted to accumulate data for the design and operation of full-scale deodorizing systems.

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.

Biofilters are a wide-spread technology over physical and chemical methods for the treatment of odor compounds because many lab and field-scale operations have demonstrated effective treatments for gas streams contaminated with a low concentration of various odor compounds. Therefore, biofilter processes are classified as one of the best available control technologies in Europe. However, biofilter performance can not be reliable when they are operated at dynamic loading conditions over an extended period. Several methods have been proposed and implemented to overcome some operational problems such as nutrient depletion and clogging. In spite of these efforts, conventional biofilters require improvement to effectively control high concentrations of odor compounds. As a results, additional attempts to resolve the problems and expand biofilter application range are being studied.