© Greg Lutz
Developed by a research team led by Professor Xie Yonghong from the Institute of Subtropical Agriculture at the Chinese Academy of Sciences, the multi-stage treatment system integrates a sedimentation pond, two filtration dams, an aeration pond, a biological filter pond, and a submerged plant stabilisation pond, creating a comprehensive water remediation framework. A demonstration site was established at a bullfrog aquaculture facility in the Datong Lake region of Yiyang City, offering a real-world test of the system’s effectiveness.
Initial results indicate that the wetland system is highly effective at removing pollutants, achieving a removal efficiency exceeding 60 percent for both total nitrogen and total phosphorus. These reductions significantly decrease the environmental impact of aquaculture effluents. However, seasonal variations influenced the system’s performance, with nitrogen removal remaining consistent, while phosphorus removal showed fluctuations throughout the year.
The aeration pond played a particularly important role in optimising dissolved oxygen levels, which enhanced phosphorus removal during the summer months and nitrogen removal in the cooler months. The biological filter pond and aeration pond also hosted a diverse microbial community, with epiphytic bacterial species diversity significantly higher in these sections compared to other parts of the system. This suggests that these treatment zones create an ideal microenvironment for beneficial bacterial colonisation and activity, which is essential for wastewater purification.
"This technology not only optimises water purification processes in intensive aquaculture systems, but also deepens our understanding of the synergistic interactions between aquatic plants and epiphytic biofilms, revealing their crucial roles in pollutant removal from bullfrog aquaculture wastewater," said Professor Xie, corresponding author of the study, as reported by Phys.org.
