Resource and Energy Utilization of Swine Wastewater Treatment: Recent Progress and Future Directions

Livestock and poultry farming, as a crucial component of agricultural production, poses a substantial threat to the ecological environment due to the discharge of wastewater. In recent years, researchers have proposed various resource treatment technologies for livestock and poultry breeding wastewater. However, a comprehensive discussion regarding the limitations and avenues for optimizing resource utilization technologies for livestock and poultry farming wastewater treatment is notably absent in existing literature. This paper takes swine wastewater as an illustrative case and undertakes a review of the advantages, disadvantages, and optimization directions of resource treatment technologies, including physical and chemical technology, microbial metabolism, microbial electrochemistry, constructed wetlands, and microalgae-based techniques. Based on mass balance, the recovery rates of various treatment technologies are estimated, and it was found that microbial electrochemistry and constructed wetland techniques may become the mainstream for resource utilization in the future. Furthermore, this paper emphasizes that in addition to resource efficiency, the optimization of resource utilization technologies for swine wastewater should also focus on the following aspects: (1) striking a balance between environmental impact and economic benefits; (2) reducing the cost of resource and energy utilization; and (3) safeguarding environmental and ecological security.