Introduction

Odorous gas emissions from swine slurry pits are major concerns affecting environmental quality, worker health, and the sustainability of livestock production systems. In slurry pit, the accumulation and decomposition of organic materials can accelerate the generation of odorous compounds such as ammonia and hydrogen sulfide. Therefore, improving manure handling through simple and effective solid–liquid separation methods may help mitigate these emissions. This study evaluated the potential of a laboratory-scale surface filtration-based solid–liquid separation system to reduce odorous gas emissions from swine slurry pits.

Materials and methods

The experiment was conducted using 60-L laboratory-scale reactors: a control without surface filtration and a surface filtration treatment equipped with a filter installed at the upper surface of the reactor. The surface filter was designed with 10-mm-diameter holes to retain larger solid particles while allowing the liquid fraction to drain into the lower reactor. Each treatment was performed in triplicate. Odor characteristics were assessed using dynamic olfactometry. Odorous gases, including ammonia (NH₃) and hydrogen sulfide (H₂S), were measured. In addition, odor-related volatile organic compounds, including phenol, p-cresol, indole, and skatole, were analyzed.

Results and discussion

The surface filtration treatment was designed to reduce the accumulation of degradable solids in the lower liquid storage zone, which subsequently limit microbial decomposition and the formation of odorous compounds. By retaining solids at the upper layer and facilitating separation of the liquid fraction, the filtration system was expected to improve manure stratification and reduce the odor emission by 70%. This indicates that retaining feces above the filter platform significantly mitigate reduction effieciency (p<0.05). Total VFA concentration was significantly reduced in the treatment compared with the control (p < 0.05). Control showed strong VFA accumulation, especially around day 15, indicating active anaerobic decomposition and higher odor potential. These observations suggest that surface filtration effective management approach for mitigating emissions of odorants and harmful gas from swine slurry under laboratory-scale conditions.

Conclusion

Surface filtration-based solid-liquid separation reduced odor emissions from the swine slurry pit simulation by limiting feces-urine mixing and reducing organic load in the slurry layer. The treatment showed lower odor concentration, higher odor reduction efficiency, significantly reduced VFA accumulation, higher pH, and lower EC compared with the control. These results suggest that surface filtration is an effective pre-treatment strategy for mitigating odorant generation from swine slurry pits.

Key words: Odor mitigation, solid–liquid separation, surface filtration, swine slurry pit

Acknowledgemnet

This work was carried out with the support of “Research Program for Agriculture Science and Technology Development (Project No. PJ01708401)” Rural Development Administration, Republic of Korea.